Viruses

Viruses are so plentiful that if all viruses on earth were placed in a line, the line would extend for 200 light years. Given that one light year is about 5.9 TRILLION miles long, you can see that we are exposed to a lot of viruses. The good news is that not all of these viruses can infect people. However, when viruses do cause an infection, they commandeer the cells they infect, causing them to make more viruses — thousands more. In some cases the symptoms of a viral infection include a rash.

Bacterial skin infections

When scientists estimate the number of bacteria that exist on the earth at any point in time, the result is 100 million times the number of stars in the universe. That is to say, the earth is teeming with bacteria, but like viruses, not all bacteria cause diseases in people. Indeed, some bacteria have evolved so that we rely on their presence as much as they rely on ours to survive. Unfortunately, in some cases bacteria do cause disease and in some of these cases, rashes are a symptom of this infection.

Parasites

Parasites are organisms that live in a host and rely on the host for food and, therefore, survival. Most of the time these organisms are harmless, but on occasion they can cause disease. Although many parasites can cause disease, one that most commonly causes a rash illness is scabies.

Fungi

About 1.5 million types of fungi co-exist with us on earth; however, only about 300 are known to cause illnesses in people. Because fungi generally like warm, moist environments and some digest keratin, skin infections caused by fungi are fairly common.

Allergic reactions or irritants

In some cases rashes are the result of an allergic reaction. The reaction may be localized or affect the entire body.

Unknown origin

In a few cases scientists are not sure what causes certain diseases or conditions. Kawasaki syndrome is one such example.

This disease gets its name from the small blisters that look like chicken peck marks. Chickenpox used to be confused with smallpox.

• How it spreads: Chickenpox is spread through respiratory droplets in the air.
• What it looks like: Itchy, sometimes painful, fluid-filled blisters usually first appear on the face and chest then spread outward onto arms and legs. Crops of blisters appear over a period of a few days and then rupture and crust over. Typically people have 250 to 500 blisters and illness lasts for about a week. Different stages of the rash are usually found in the same area (i.e., red lesions flat to the skin, red bumps raised from the skin, and fluid-filled blisters on a red base).
• How long it lasts: The rash typically lasts for about 5-10 days.
• Other symptoms: Fever and general feelings of sluggishness and fatigue may appear around the time that the rash develops or precedes the rash by 1-2 days.
• Related health problems: The virus can also infect the lungs, brain, testicles, liver, kidneys or membrane surrounding the heart. In some cases, bacterial infections, such as with group A streptococcus, occur in one or more of the chickenpox lesions. This is the most common reason for children to be hospitalized with chickenpox.
• How to avoid it: A vaccine has been available since 1995; in the U.S. children typically receive a dose at 12-15 months of age and a second dose before starting school, around 4-6 years of age.
• Other things to know:
  • While not the most contagious infectious disease, chickenpox is still considered to spread easily. If ten susceptible people are exposed to a person with chickenpox, such as living together in the same house, 6 to 10 of them are likely to become infected as well.
  • Chickenpox infections are most common during the winter and the spring. While most are mild, for some people, disease can be serious.
  • People with compromised immune systems, such as those undergoing chemotherapy or radiation therapy and those taking high dose steroids, are at increased risk of experiencing severe disease and death from chickenpox infections.
  • Pregnant women infected with chickenpox are more likely to deliver babies damaged by chickenpox or experience fetal death as a result. Likewise, babies born to moms infected with chickenpox right before or immediately after birth are more likely to experience severe disease since they do not have the benefit of maternal antibodies. For these reasons, women who are not immune to chickenpox are recommended to get the chickenpox vaccine before becoming pregnant.
  • Once someone has had chickenpox, they are susceptible to experiencing shingles later in life because the virus lives silently in nerve cells for the rest of the person’s life. People who get the chickenpox vaccine can still get shingles, but they are less likely to do so, and if they do, the episode tends to be less severe when compared to someone who had a chickenpox infection.

This infection is also known as “hand, foot and mouth disease” because of the sites usually affected by the virus.

• How it spreads: Coxsackie virus is spread through respiratory droplets or contact with contaminated objects.
• What it looks like: The rash, which consists of small red spots that blister, often begins toward the back of the mouth. The rash on the skin develops as red spots that can be flat or raised and often occur on the palms of the hands or the soles of the feet. However, they can also occur in areas such as knees and elbows, buttocks or genital areas. The rash on the skin progresses over a period of about 1 to 2 days.
• How long it lasts: Course of illness is typically about one to one and a half weeks, but the rash doesn’t develop until a few days after the beginning of the infection.
• Other symptoms: People with this illness typically have a fever before the appearance of mouth sores and before the rash is noticed on the skin. The sores in the mouth tend to be painful, making it difficult to eat and drink. Infected individuals typically feel unwell and don’t have much of an appetite. They may also have a sore throat.
• Related health problems: Dehydration can occur if the infected person finds it difficult to eat or swallow. Other complications are rare; however, on occasion infected people may develop brain swelling, meningitis or loss of fingernails or toenails, difficulty breathing, muscle weakness or loss of reflexes, or increased heart rates.
• How to avoid it: A vaccine does not exist to prevent this disease, so people should practice good hygiene, such as frequent hand-washing; regular cleaning and disinfection of surfaces and toys; and avoiding close contact, such as kissing, hugging or sharing utensils, with infected individuals.
• Other things to know:
  • On occasion people can get this infection after swallowing contaminated recreational water, such as in swimming pools that are not properly treated with chlorine.
  • People are most contagious during the first week of illness and can spread the disease even when they don’t have symptoms.
  • This illness typically occurs commonly in children less than five years old and is more common from spring to fall.

The rash associated with Fifth disease is commonly referred to as a “slapped cheek” rash.

• How it spreads: Caused by a virus known as parvovirus B19, that is spread through respiratory droplets, such as from coughing and sneezing.
• What it looks like: The rash that develops during an episode of fifth disease typically starts on the face and can spread to the chest, back, buttocks or limbs. The rash tends to be itchy and can be more or less visible over a period of weeks. When the rash starts to go away, it may have a lacy appearance.
• How long it lasts: The rash usually lasts about 7 to 10 days.
• Other symptoms: First symptoms include fever, runny nose and headache. Later during the infection, joints may swell and become painful. The joint pain is more common in adults, particularly women and typically lasts 1 to 3 weeks, but can last for months.
• Related health problems: Fifth disease is typically mild and does not often lead to complications; however, people with weakened immune systems are at increased risk of developing chronic anemia as a result of this infection.
• How to avoid it: No vaccine exists for this disease; however, transmission can be curbed by good hygiene habits such as regular hand-washing, covering coughs and sneezes, not touching your eyes, nose or mouth; avoiding people who are sick and staying away from others when you are sick. The important point to remember about this infection is that people are most contagious before the rash develops during a period of general, cold-like symptoms.
• Other things to know:
  • Pregnant women who are infected can transmit this virus to their unborn babies. In most cases the infection is not a problem for the woman or the baby; however, in a small number of infected pregnant women (about 5 of every 100), the baby will develop anemia and the woman will miscarry. For this reason pregnant women who are not immune to this virus should avoid others who are infected. A blood test is available for women concerned about their immunity to this virus.

Measles is one of the most highly contagious viral infections; in fact, susceptible people can be infected simply by breathing the same air as someone who is infected —even as long as two hours after that infected person has left the area.

• How it spreads: Measles is spread by small respiratory droplets that hang in the air.
• What it looks like: Before the rash develops, Koplik’s spots often appear in the mouth. These small white spots appear on the lining of the cheeks, roof of mouth and inside the lips and have bluish white centers. They look like grains of sand. Approximately, one to two days later a rash develops over the entire body. The rash, typically starts at the hairline, proceeds to the trunk and then to the limbs over a three- to four-day period.
• How long it lasts: Koplik’s spots tend to last about 3 or 4 days; body rash develops over 3-4 days and disappears after about a week.
• Other symptoms: The earliest symptoms to appear during a measles infection are fever, lack of energy, pink, watery eyes and cough. These symptoms occur about 10-14 days after exposure and last about 2-4 days; fevers can be as high as 105 degrees Fahrenheit.
• Related health problems: Cases of measles can be complicated by ear infections, pneumonia, diarrhea, brain swelling, short-lived decreases in platelet count (leading to problems with blood clotting), as well as involvement of the liver, appendix, heart and kidneys. In rare cases, a condition known as subacute sclerosing panencephalitis or SSPE may develop. This condition is uniformly fatal and may not appear until years after the measles infection. Children who get measles early in life, e.g., before 1 year of age, are at increased risk of developing SSPE. Death may also occur from other complications, such as pneumonia.
• How to avoid it: A vaccine to prevent measles has been available since the 1960s; it is currently given as part of the MMR vaccine to children at 12-15 months of age and again at 4-6 years of age before starting school.
• Other things to know:
  • Measles and smallpox used to be confused.
  • Although measles was virtually eliminated from the U.S., in 2000, cases have continued to be introduced through travelers to and from countries in which the disease has persisted at high levels.
  • In Africa, so many children succumb to measles that families wait to name their children until the threat has passed. Find out more about this from the Measles & Rubella Initiative.
  • As is true for most infectious diseases, people infected with measles are the most contagious in the period before their rash develops. This is particularly frustrating when trying to stop the spread of disease because the symptoms at that juncture appear similar to the common cold.

This viral rash is caused by a virus known as molluscum contagiosum and causes flesh-colored bumps that typically have indentations or white cores in the center of them. When they are resolving, the lesions will become very red due to the body’s immune response to the virus.

• How it spreads: This virus is spread by touching the rash of an infected person or through contaminated toys, clothing or towels. Occasionally, the virus can be spread through sexual contact when the infection is near the genital area although many children spread the molluscum innocuously to their own genital areas by accident.
• What it looks like: The molluscum rash typically looks like small bumps with a dimple in the middle. The bumps may be white, pink or the color of skin. Most of the time they are firm, smooth bumps that are painless although they may become swollen, red and sore when resolving.
• How long it lasts: This rash typically lasts between 6 and 18 months and goes away without treatment.
• Other symptoms: None.
• Related health problems: Scarring may occur in about 7 of every 100 patients; otherwise, most people do not experience complications with the exception of people with weakened immune systems. For these patients, bacterial co-infections and difficulty preventing spread may be encountered.
• How to avoid it: This disease is contained by proper hand washing as well as taking precautions, such as avoiding activities such as contact sports and swimming when you are infected. In addition, people with the infection should keep the sores covered.
• Other things to know:
  • In people with weakened immune systems, the rash may last longer, spread more easily to other parts of the body and be more difficult to rid.
  • This infection is so common that up to 10 of every 100 children may be infected with molluscum contagiosum at any point in time.

This rash illness, also called sixth disease, roseola infantum or exanthem subitem, often affects young infants and resolves on its own without treatment. It is caused by some types of herpes virus.

• How it spreads: This infection is spread through respiratory droplets.
• What it looks like: A rash occurring during a roseola infection usually starts when the preceding fever breaks; it appears as small pink bumps with a slightly raised surface. The rash begins on the chest and then spreads to the face and limbs.
• How long it lasts: The roseola rash typically lasts one to three days before beginning to fade.
• Other symptoms: The first sign of roseola is often a high fever which lasts for 3 to 5 days.
• Related health problems: Because of the high fever (about 103 degrees Fahrenheit), some children experience fever-induced seizures.
• How to avoid it: No vaccine is available, so the only way to prevent infection is to keep infected children away from other infected children.
• Other things to know:
  • Infants between 6 and 13 months are most commonly infected with this virus; however, older children can be infected as well. About 95 of every 100 infections occur in children younger than three years of age.
  • Roseola is spread before symptoms develop, so it can be difficult to contain transmission.

Also known as German measles, this viral infection is not typically severe in children; however, when pregnant mothers are infected, their babies often are born with severe physical and mental impairments, such as autism, deafness, cataracts, or heart defects. The virus can also cause miscarriages and premature births.

• How it spreads: Rubella is spread by droplets in the air.
• What it looks like: The rash does not typically appear until about 2 to 2 1/2 weeks after exposure to the virus. Only about 2 of every 3 people develop a noticeable rash; however, when it does appear, it begins on the face and neck before spreading downward to the rest of the body over a one to three day period before beginning to fade.
• How long it lasts: Rash develops and fades over a 1-3 day period.
• Other symptoms: People who are infected do not typically exhibit symptoms during the first week; however, during the second week, swollen glands may occur followed by a low fever, lack of energy and mild conjunctivitis.
• Related health problems: The primary complication of rubella is the main reason people seek to prevent this illness. Known as congenital rubella syndrome, or CRS, this condition affects unborn babies when their mothers are infected during pregnancy. The infection typically affects all organs of the fetus resulting in a vast array of health issues in those children who survive. Women infected in the first trimester of pregnancy are most likely to deliver babies who are severely affected. Cataracts, glaucoma, deafness, brain swelling, mental impairment, and autism are common outcomes for children born to mothers who had rubella during pregnancy.
  
  Other complications resulting from rubella include joint pain and swelling, brain swelling, and a temporary drop in platelet counts resulting in blood clotting issues.
• How to avoid it: The rubella vaccine has been available since 1969 and is offered as part of the MMR vaccine, given to children at 12-15 months of age and between 4-6 years of age.
• Other things to know:
  • The rash is typically more pronounced after a hot shower or bath.
  • The rubella vaccine is an example of immunizing one person to protect another in that we immunize children, particularly young girls, to protect their future offspring.

Shingles, also known as zoster, is caused by the same virus as chickenpox. The disease occurs when the virus living silently in nerve cells reawakens. The people most susceptible to shingles are the elderly and those with weakened immune systems.

• How it spreads: Only people who have had chickenpox (or the vaccine) can get shingles; however, people with shingles can infect someone who has not had chickenpox, such as an infant who is too young for the chickenpox vaccine. In these cases, the non-immune person would need to come into contact with the shingles rash. So people with shingles do not need to avoid those susceptible to chickenpox, but they should shield them from the rash.
• What it looks like: Because the virus lives silently in nerve cells after a chickenpox infection, shingles rashes tend to appear along a nerve path, such as by the eye or around the waist. The rash typically develops in clusters near the involved nerve over a 3 to 4 day period.
• How long it lasts: The rash lasts for about a week to a week and a half until the sores crust and begin to heal.
• Other symptoms: Pain in the area of the affected nerves is typically the first symptom to appear. The pain may be shooting, aching or throbbing and can be constant or intermittent. This pain usually occurs 3 to 4 days before the rash, but can be present for a week or more before the visual symptoms. The area experiencing the pain is often extremely itchy as well. Pain associated with the area may increase and be severely debilitating preventing affected individuals from daily activities including going to work or even getting dressed.
• Related health problems: The severe pain associated with shingles can remain for months after the episode. Known as post-herpetic neuralgia or PHN, the long-lasting pain associated with shingles infections is the third most common cause of chronic neuropathic pain in the U.S. each year.
  People can also experience bacterial co-infections associated with the sores, motor damage, such as weakness in limbs, or bowel or bladder dysfunction if associated nerves are involved.
• How to avoid it: An effective vaccine, known as Shingrix, is recommended for adults 50 years and older. It is given in two doses separated by two to six months. People who got an older version, which was a live, weakened  version called Zostavax, should still get Shingrix.
• Other things to know:
  • Because of the appearance of pain before the rash, people are often evaluated for conditions such as heart attack, appendicitis or kidney stones. Indeed, more than ten percent of the costs associated with shingles are due to the costs incurred prior to the appearance of the rash.
  • People who get the chickenpox vaccine can still get shingles, but they are less likely to do so and if they do, the episode tends to be less severe when compared to someone who had a chickenpox infection.
  • The pain associated with shingles has been described as one of medicine’s most debilitating pains.
  • About 5 of every 100 people who get shingles will get it again; therefore, having shingles in the past is not a reason to forego vaccination.

Smallpox used to claim so many lives that it was referred to as the “angel of death.” Now, thanks to the smallpox vaccine, this disease no longer infects anyone in the world. The last time anyone in the world was diagnosed with smallpox was in 1977.

• How it spreads: Used to occur from droplets in the air.
• What it looks like: The rash started inside the mouth, progressed to the face and forearms, and finally to the legs and body trunk. The blisters were typically concentrated on the face, arms and legs and could be found on the palms of hands and bottoms of feet.
• How long it lasts: The rash progressed to different stages over about six days.
• Other symptoms: First symptoms to appear were high fever, lack of energy, physical weakness and headache and backache. These symptoms typically began 2 to 3 days before the rash appeared and about one and a half to two weeks after exposure to the virus.
• Related health problems: People can experience infections with bacteria in the skin lesions, pneumonia, sepsis (bloodstream infection), swelling of joints or brain, blindness, bone infections and fetal death if a pregnant woman is infected.
  
  Survivors often suffer from lifelong conditions such as blindness, limb deformities and facial pockmarks.
• How to avoid it: No cases exist anywhere in the world and the virus does not infect animals, so unless the virus was reintroduced in an act of bioterrorism, we do not need to worry about becoming infected. If the virus was to re-emerge from a human act, a vaccine exists. However, the vaccine has a fairly high side effect rate, so in the absence of an actual threat of disease, the benefits do not outweigh the risks.
• Other things to know:
  • People are only contagious with this infection during the period when they have the rash and before it has crusted. This is important for containing the spread because you can tell who has the disease and isolate them.
  • Following the anthrax attacks in 2001, the U.S. government moved to immunize military personnel. However, at this time, only certain members of the military receive the vaccine based on deployment region and job. Find out more about this program.
  • Smallpox is the only disease that has ever been completely eradicated. This accomplishment is a testament to the power of vaccination; however, certain characteristics, such as period of contagiousness and lack of an animal reservoir, were also important to this accomplishment. While we would like to believe vaccines could make other diseases extinct, the characteristics of most will prevent us from accomplishing this. Polio and measles have been suggested as possible candidates; however, to date, neither has been accomplished.

The rash caused by Staphylococcus Aureus, known as impetigo, has honey-colored crusts and is easily spread by contaminated towels or clothes.

• How it spreads: This bacterial infection is opportunistic in that bacteria that may commonly co-exist on the skin or in the nose and throat cause an infection when a cut or break in the skin allows entrance into the body.
• What it looks like: Impetigo rashes can take two forms. The first is characterized by tiny pimples or red areas that ooze and crust with a honey-colored appearance. The second type can be described as blisters that easily break open and may spread to the face, trunk, and limbs. Infections can vary in the number of lesions and size of affected area. The rash may be itchy.
• How long it lasts: Infection may resolve in two to three weeks without treatment, but antibiotic treatment can speed the recovery.
• Other symptoms: None
• Related health problems: Skin infections that start as impetigo can progress to complications such as cellulitis, a deep skin infection or meningitis.
• How to avoid it: Keep wounds, such as cuts, scrapes and insect bites, clean and covered.
• Other things to know:
  •  People at increased risk of impetigo include those who participate in contact sports, have weakened immunity or have chronic skin conditions, such as eczema.

Caused by the same bacteria that causes strep throat, this rash is sometimes described as a “sandpaper rash” because it feels rough like sandpaper.

• How it spreads: This bacterial infection is spread through respiratory droplets, such as from coughs and sneezes. The infection can cause scarlet fever, but can also cause strep throat and the skin infection known as ecthyma.
• What it looks like: A red rash that develops on the neck, underarm and groin and then may spread over the rest of the body. The original rash evolves into fine bumps that feel like sandpaper. Creases in the skin may appear redder than the rest of the rash. As the rash fades over about a week of time, the skin around the fingers, toes and groin areas may begin to peel. The peeling can occur over a period of several weeks.
• How long it lasts: Most often, the rash develops a day or two after other symptoms; however, it can appear before any other symptoms or up to seven days after the illness begins.
• Other symptoms: The first symptoms are typically a fever and sore throat. These may be accompanied by chills, vomiting and pain in the abdomen. In addition to the sore, red throat, a person ill with scarlet fever will also tend to have a whitish coating over the tongue and the tongue may be described as a “strawberry” tongue because of its red, bumpy appearance. Other symptoms may include headache, body aches and swollen glands.
• Related health problems: People with scarlet fever can experience complications such as rheumatic fever, kidney disease, ear and skin infections, throat abscesses, pneumonia and arthritis.
• How to avoid it: Good hand hygiene, not sharing utensils, linens or other personal items, and staying away from people who are ill are the best ways to prevent this infection. No vaccine is available.
• Other things to know:
  • The red rash caused during this illness is the result of a toxin, or poison, produced by the streptococcus bacteria.
  •  In addition to strep throat and impetigo, group A strep bacteria can cause severe disease if a systemic infection occurs. Examples of these, rare, but severe infections include necrotizing fasciitis (“flesh-eating bacteria”) and streptococcal toxic shock syndrome.

The intensely itchy rash of scabies is caused by mites that burrow under the skin.

• How it spreads: Scabies is spread by person-to-person contact such as to household members or sexual partners. Although the disease is not typically spread through casual contact such as a handshake or hug, it can sometimes be spread through exposure to clothing, towels, or bedding.
• What it looks like: The rash caused by scabies resembles small pimples or bumps that are intensely itchy; they may occur over the whole body or in areas of folds, such as webbing of the fingers, elbows, underarms, wrists, palms, soles, waist or in genitals, nipples or buttocks, especially when spread between sexual partners. Infected infants may also have the rash on the head or face. People infected for the first time may not have noticeable symptoms for up to two months after the infection; however, they can transmit the infection during this time.
• How long it lasts: The rash will last throughout the duration of infestation with the mites. When mites are living on a person, they can survive for one to two months.
• Other symptoms: Intense itching, particularly at night. Burrows that are small and either grayish-white or skin colored lines on the skin surface may be noticeable.
• Related health problems: Because of the itching, sores can be scratched open leading to infections caused by opportunistic bacteria, such as those that cause impetigo. These co-existing bacterial infections can lead to inflammation of the kidneys.
• How to avoid it: Hand washing after potential contact and avoidance of infected skin are the best ways to avoid this infection.
• Other things to know:
  • The itchiness of the rash may intensify at night.
  • Scabies that are not on a person live only 2 to 3 days and will die if exposed to high temperatures (122 degrees Fahrenheit) for ten minutes.
  • People with immune compromised systems, such as the elderly, may develop crusted scabies. In these cases, the large numbers of mites make the person extremely contagious.

Find information about other parasites in the CDC’s A-Z index of parasitic diseases.

This rash is not caused by a worm. It takes the form of a circle and spreads outward; it is caused by a fungus that likes moist areas, but can also live on surfaces and household items and spread by communal use of hats or hairbrushes. The fungus can also be spread during contact sports, like wrestling.

• How it spreads: Ringworm infections are transmitted by contact with an infected person or animal or by contact with personal items or surfaces used by infected people, such as clothes or hairbrushes.
• What it looks like: Rashes caused by ringworm can occur on almost any part of the body and often take the shape of a ring that is red on the outside and skin-colored in the middle. The ringed rash is typically scaly and raised and may crack or blister.
• How long it lasts: With treatment using antifungal lotions or pills, the infection typically heals in about a month.
• Other symptoms: If the ringworm occurs on a part of the body that has hair, such as the scalp or on a bearded face, the hair may fall out. If nails are infected, they may become thick and discolored.
• Related health problems: Infected areas may rarely become warm, red and tender if an abscess or cellulitis occurs. Bacterial infections may complicate the infection if it is scratched open and the bacteria, such as those that cause impetigo, can enter the wound.
• How to avoid it: Preventing others from coming into contact with the wound or from sharing personal use items helps to prevent transmission to others. Keeping feet covered in areas such as gyms, pools and locker rooms is also of value.
• Other things to know:
  • If the affected area is illuminated with a blue light in a darkened room, certain types of fungus may glow.
  • Clothing and sheets used by infected people should be washed daily.
  • Pets with bald spots may have ringworm, so care should be taken to avoid touching or petting them.
  • Ringworm is sometimes referred to as tinea; a variety of types of tinea are known based on the location of the rash.

This fungal infection is easily spread around swimming pools and locker rooms where people are walking around without shoes; the fungus can then grow in shoes and cause the rash which often burns and itches.

• How it spreads: Athlete’s foot is spread by contact with the rash of an infected person or, more commonly, by contact with contaminated objects or areas, such as locker room floors, gyms, or areas around swimming pools where people walk without shoes.
• What it looks like: Athlete’s foot rashes are red and scaly, often occurring between toes, but the rash can also spread to the soles and sides of the feet.
• How long it lasts: With prompt treatment and institution of prevention methods, such as keeping feet dry, the infection will typically last less than a week and a half; however, if left untreated, the infection can last for months or even years.
• Other symptoms: Intense itching, particularly after removing socks and shoes; dry, scaly skin may become chronic.
• Related health problems: The rash can spread to hands, nails or groin if the person is scratching it. Likewise, bacterial co-infections can occur in the areas of infected skin. People with compromised immunity may have difficulty clearing the infection.
• How to avoid it: Wearing footwear in areas that are known for increased risk of spread, such as in locker rooms and pool areas and not sharing personal items such as towels or shoes is the best way to prevent the spread of this infection. Keep feet dry; if your feet sweat, change your socks regularly and use different pairs of shoes rather than the same shoes every day.
• Other things to know:
  • Athlete’s foot is caused by the same fungus that causes ringworm and jock itch.
  • Some people with athlete’s foot do not realize they are infected; they think they have dry skin.

Reactions to contact with an allergen usually occur within 48 to 72 hours after exposure. Allergens can include jewelry or other metals, chemicals, soaps, cosmetics or dyes but the most classic example is “poison ivy, oak or sumac”. Contact dermatitis can also be caused by exposure to an irritant in which case the rash tends to develop more quickly after exposure. 

• How it spreads: Contact dermatitis is not transmitted from person to person; it is caused by an allergic reaction or exposure to an allergen.
• What it looks like: The rash caused by contact dermatitis is red, raised and dry looking but can be blistered; it is also typically itchy. Individual sores often have linear or geometric patterns.
• How long it lasts: The rash can develop shortly after exposure to an allergen or two to three days after exposure to an allergen depending on previous exposure and how allergic a person is. It may take up to a month to heal.
• Related health problems: If exposure to the allergen continues over a long period of time, the rash may remain and the skin will thicken. Bacterial co-infection may occur.
• How to avoid it: Identify and remove exposure to the allergen.
• Other things to know:
  • Common allergens include certain metals, such as nickel, fragrances, latex, topical antibiotics, preservatives, cosmetics, plants, airborne substances and dyes.
  • In the case of poison oak, ivy or sumac:
    • The cause is exposure to oil, called urushiol, found in these plants. The oils are present in all parts of the plant not just the leaves.
    • Burning plants that contain this poisonous oil can be dangerous if people inhale the fumes and their lungs become irritated. This is of particular concern for firefighters battling forest fires.
    • The oil can last on contaminated tools for up to five years.
    • To easily identify poison ivy and poison oak, people are often taught the reminder, “Leaves of three, let them be.” However, poison sumac does not follow this rule as it has clusters with greater numbers of leaves.
  • If working with or near plants, cover as much skin as possible, including using disposable gloves and clean tools with alcohol after use.
  • A person can be exposed to some allergens for years without problem and then the allergy develops suddenly.

This condition characterized by dry, patchy skin can be outgrown during early childhood or flare up on and off throughout life. The word “eczema” comes from a Greek word meaning “to boil over.”

• How it spreads: Eczema is not transmitted from person to person; instead it is a condition that tends to run in families who also have members with asthma and seasonal allergies.
• What it looks like: Eczema is usually scaly, pink patches that are slightly elevated. The rash is itchy.
• How long it lasts: Rashes occur during flare ups, and children may go for long periods without having a rash. While some children outgrow the condition by the age of five or six years old, others experience symptoms of eczema throughout life.
• Other symptoms: None.
• Related health problems: Sores can be complicated by bacterial co-infections.
• How to avoid it: Flare-ups occur periodically, but affected people should use gentle non-soap cleaners, moisturize skin regularly, and minimize stressors on the skin, such as heat, detergents, chemicals and smoke.
• Other things to know:
  • Children with eczema are more likely to have allergies.
  • Symptoms of eczema may reappear during puberty.

This rash often appears as a result of excessive sweating, such as in hot, humid climates. The rash typically appears in folds in skin, such as elbows, waists, and neck.

• How it spreads: This rash is not spread from person to person, but rather it is caused by sweating, such as occurs during hot, humid weather or in babies who are dressed too warmly.
• What it looks like: The rash of heat rash is characterized by clusters of red or pink bumps that resemble pimples; the rash tends to appear in areas with skin folds, such as elbows, neck, groin and under breasts. The rash may be itchy.
• How long it lasts: The rash typically lasts 3 to 4 days.
• Other symptoms: None.
• Related health problems: Bacterial co-infection can occur potentially causing redness and swelling of the affected area; however, this rarely happens.
• How to avoid it: Dress with an appropriate number of layers, particularly in warmer weather and keep skin cool and dry.
• Other things to know:
  •  Also known as prickly heat, this condition most often affects young infants.

Caused by the release of a chemical called histamine during an allergic response, the itchy, red rings and bumps typically disappear within 24 hours.

• How it spreads: This condition is not transmitted from person to person, but rather is the result of an allergic reaction.
• What it looks like: The rash appears suddenly in the form of pale red bumps that vary in size and can join together to form larger areas.
• How long it lasts: Hives typically last hours to less than one day, but can take weeks to disappear completely.
• Other symptoms: Swelling can occur around the eyes and lips as well as on hands, feet and genitals. This swelling can also, in some cases, extend to the throat, tongue or lungs leading to respiratory distress.
• Related health problems: If swelling impairs airways, this condition can be life threatening and lead to death if not quickly treated.
• How to avoid it: Because this condition is the result of an allergic reaction, prevention is accomplished by identifying and avoiding the allergen. In many cases of hives, a cause cannot be found.
• Other things to know:
  • Typical allergens can include foods, medicines, physical stimulation of the skin, such as from extreme temperatures, vibration, excessive scratching or exercise.
  •  Foods that cause allergies tend to be those consumed as fresh, rather than cooked, products, including nuts, chocolate, fish, tomatoes, eggs, berries and milk.

This systemic illness is also characterized by fever, swelling of the hands and feet as well as the mouth, lips and throat, and irritated, red eyes and swollen glands in the neck. The tongue is described as a “strawberry tongue” because of its bumpy, bright red appearance. The disease is named after the researcher from Japan who first described the disease.

• How it spreads: It is unclear how this condition is transmitted, but the current belief is that the disease is not contagious from person to person.
• What it looks like: The rash associated with Kawasaki syndrome tends to appear on the trunk and genital areas, but skin on the palms of the hands and soles of the feet may also be red and swollen. As the infection progresses, the skin on the hands and feet may peel, often coming off in large pieces.
• How long it lasts: Symptoms gradually clear over several weeks.
• Other symptoms: Symptoms typically include a high fever (102 degrees Fahrenheit) for at least five days, swelling of the hands, feet, mouth, lips and throat; red, irritated eyes; and swollen glands. Later during infection infected individuals may have joint pain, vomiting and diarrhea.
• Related health problems: People with Kawasaki syndrome can experience complications, such as aneurysms and heart disease, which can be prevented with early recognition of the disease and treatment with intravenous immunoglobulin.
• How to avoid it: Because the cause of this condition is not well understood, it is difficult to prevent it.
• Other things to know:
  • This condition was first described in Japan and most often affects children younger than five years old.
  • Boys and children of Asian descent tend to be affected more frequently.
  • This condition is diagnosed more often from winter to spring.

If you are looking for additional images of rashes, particularly those shown as they appear on darker skin tones, check out the Instagram account, “Brown Skin Matters.”

Content references

• Centers for Disease Control and Prevention. Types of Fungal Diseases.
• Plotkin SA, Orenstein WA and Offit PA. Vaccines. Sixth Ed.2013. Elsevier Saunders
• Wassenaar, T. Bacteria: The Benign, the Bad, and the Beautiful. 2012.Wiley-Blackwell, Inc. Hoboken, NJ
• Williams, G. Angel of Death: The Story of Smallpox. 2010. Palgrave-Macmillan. New York, NY
• Wolfe, N. The Viral Storm: The Dawn of a New Pandemic Age. 2011. Times Books, New York, NY

• The following images appear with permission from VisualDx: athlete's foot, fifth disease, heat rash, Kawasaki syndrome, roseola, rubella, scarlet fever, scabies
• Public Health Image Library, CDC: chickenpox (content provider: CDC/Joe Miller), measles (content provider: CDC), smallpox (content provider: CDC/Dr. Charles Farmer, Jr.)
• CHOP Images – coxsackie, molluscum, shingles, impetigo, ringworm, contact dermatitis, eczema, and hives