Your symptoms are suggestive of Erythema Ab Agne. This is usually caused by either intake of a new prescription drug like penicillin or an OTC drug like aspirin, or can also occur secondary to some contact with hot waves like from laptop or computers. Many times it is not possible to find out the cause, however since most are self limited within 4-6 weeks of onset of symptoms, it is not imperative to do so. I would recommend taking Tablet Claritin 10 mg once or twice a day for 2 weeks + calamine lotion over the affected areas whenever symptoms occur and seeing whether they recur on stopping the medicine after 2 weeks. Hope this information is useful, please feel free to ask if you have any queries. Please feel free to ask if you have any queries.