rash on buttock

terrible itchy rash on my buttock and my upper thighs. some itchy dry skin on legs. little bumps and sort of a hive swelling over area. follows pattern of toilet seat. crazy itchy mostly at night and late in the day. started several months ago. outbreaks last for a few weeks, clears up-sort of, and then is back again. GP didn't have a clue what it was but game me a cream...and sent me to derm. Biopsy of the rash...still waiting. Doesn't look as bad as it itches...Please help. driving me crazy!

[Bhupinder Kaur, MD]

Hello,

Without examination,confirmation of a diagnosis is tough but it can be due to contact dermatitis to the toilet seat/toilet cleaner,eczema,fungal infection or hives.

Eczema is a form of chronic dermatitis (rash).Allergic reaction is one of the important causes of eczema. Hives (medically known as urticaria) are red, itchy skin rashes that have a tendency to change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours.

Take some over the counter oral antihistaminics like benadryl or Claritin,Sometimes they are required for prolonged periods.Since benadryl causes drowsiness so can be used at night to get urticaria(itching) control. Short courses of oral cortisone or steroids are taken for short periods (one to three days) to settle more severe symptoms.Application of calamine and mild steroid cream like dermacort will also help in controlling itching.

If the symptoms become severe,then it can be a case of chronic urticaria which needs further evaluation as it may be due to auto antibodies.A dermatologist’s evaluation is mandatory.

Hope it helps .Take care and pls do keep us posted in case you have any additional queries.Kind regards.