Dr. Alan Greene on Childhood Rashes

I have a 9-year-old son who has a raised rash like chickenpox. I know this is not chickenpox because my children have had it. It has spread up onto his upper legs and his bottom. I have put some cortisone (over-the-counter) on it, but it seems to be getting worse. There have been no changes in soap or anything he uses on his body. What could this be?

Some of the most common causes of raised, itchy red bumps at that age include insect bites, such as flea bites, or tiny arthropod bites, such as scabies. Hives are also common at that age. They are an allergic reaction, usually to something within the body -- not on the surface like soap. Medicines, especially antibiotics, can trigger hives. They can also be triggered by many foods, most commonly fish, shellfish, nuts, eggs, and peanuts, and by many food additives such as dyes or benzoates. They can also be caused by things that are inhaled, such as pollens, molds, and animal danders.

Hives can also be caused by allergic reactions to infections -- viruses or bacteria. They can even be the first symptom of a parasite infection. Less often, they are caused by something touched -- usually plant substances (like stinging nettle), animal saliva or animal parts (cat scratch, moth scales) or a drug. Most of the time, we never find the trigger for a child's hives. If you are not sure what the rash is, it may be wisest to have it looked at so you know what you are dealing with and what to do.

The information on this Web site is designed for educational purposes only. It is not intended to be a substitute for informed medical advice or care. You should not use this information to diagnose or treat any health problems or illnesses without consulting your pediatrician or family doctor. Please consult a doctor with any questions or concerns you might have regarding your or your child's condition.