Each year, more than eight million office visits are made to primary care physicians for rashes and other dermatologic concerns in pediatric patients. Skin rashes can be a great source of anxiety for parents, especially since the causes range from infections (bacterial, viral, fungal or parasitic) to contact dermatitis, eczema or allergies.
Measles and chicken pox can be prevented with a vaccine and have become less common in the United States due to immunization. But parents declining immunization for their children have left segments of our population vulnerable to the complications of these viruses, which can include death. Therefore, recognition of symptoms is important.
Measles usually begins with a high fever, sensitivity to light and a dry hacking cough, and is followed by continued cough, runny nose and red eyes. After a few days, an itchy, red rash develops behind the ears, spreading downward.
Chicken pox begins with a low-grade fever and fatigue, and is followed by little fluid-filled blisters on a red base. The rash usually begins on the face and trunk, spreading to the arms and legs. It heals within five to 10 days with a scab or crust forming over the blisters.
Hives are itchy, raised bumps that occur individually or in groups. Hives can be large or small, and typically come and go in different areas of the body, rarely staying in the same spot for longer than a few hours. Hives are often associated with acute allergic reactions, but can also be due to underlying infections with streptococcus or mycoplasma, the cause of walking pneumonia.
Hives appearing suddenly may indicate an allergic reaction to a known or unknown trigger, including foods, antibiotics or environmental allergens. Patients with food allergy may develop hives and/or a severe allergic reaction known as anaphylaxis upon ingestion of, and in some cases contact with, the allergenic food. The most common food allergies in the U.S. include milk, egg, soy, wheat, peanuts, tree nuts, fish and shellfish. Food allergies are diagnosed using a thorough history and skin prick or blood tests.
Exposure to an antibiotic may sensitize a patient who is destined to be allergic upon the next exposure with the same antibiotic. One of the most commonly diagnosed antibiotic allergies is penicillin allergy. Skin testing for penicillin allergy is standardized and available in the U.S.
Environmental allergies can also result in hives. Typical indoor allergies include dust mite, roach, cat and dog, while outdoor allergens include pollens from grasses, trees or weeds, and environmental molds.
When hives recur for more than six weeks, the underlying cause is often never found. However, effective treatments are available. Antihistamines are the mainstay of treatment, and a newer medication, omalizumab, may be used for certain tough cases. Consultation with an allergist can help sort out the triggers for hives and manage the symptoms.
Another very common allergic rash in children is eczema. Known as the itch that rashes, scratching makes eczema worse, starting a vicious cycle of itch and rash. Eczema can be mild or severe, and is highly associated with food allergies in infancy and can be worsened by environmental factors.
Eczema appears on different parts of the body from infancy to childhood, often starting on the face and exterior surfaces of the elbows and knees but changing over time to affect the inner creases of the elbows, behind the knees, face, arms and legs. It is intensely itchy and dry, although in severe cases the skin can actually ooze and have open areas due to scratching that become super-infected with staphylococcus or even herpes.
Eczema is a chronic condition. It is treated with a regular skin care regimen of emollients, topical steroid medications or other topical non-steroidal medications and elimination of exposure to allergic triggers. By following these steps, eczema tends to improve during childhood.
Some rare primary immune deficiencies are associated with eczema, as well as severe, recurrent or difficult to treat infections. In these cases, more testing may be needed, so your pediatrician would likely refer you to an immunologist.
When to Visit the Pediatrician
If you suspect your child has measles or chicken pox, seek immediate medical attention. Childhood rashes often share similar characteristics that make diagnosis difficult based on appearance alone. Therefore, when in doubt about a rash, consult your pediatrician.
You may be referred to a pediatric allergist/immunologist who can help distinguish rashes due to various causes, including infection, food allergies, environmental triggers or medications, and will determine the appropriate treatment for your child.
Elena Perez, M.D., Ph.D., is a pediatric immunologist at UHealth – the University of Miami Health System. Kelly Marie Schermer is a medical student at the University of Miami Miller School of Medicine. For more information, visit UHealthSystem.com/patients/pediatrics.