Hello, so did he have scabies after all? An allergic reaction may be elicited by the mite. This reaction may last even for weeks after the parasite has been eliminated. If the dermatologist is certain that this is not scabies then treating the allergy would require antihistamines and perhaps corticosteroids. In most cases allergic reactions are expected when trying new drugs. Sometimes a drug that has been used uneventfully for many years may start to cause allergic reactions. Substituting the potential offender is the way to go. You should talk with your doctor for the best options here. I would have started with triamterene/HCT which sounds like the most likely drug to cause a reaction between the drugs you ve been taking. I hope I ve answered your question. Please let me know if you need further assistance. Kind Regards, Dr Panagiotis Zografakis