Thanks for the query. There could be multiple reasons to your clinical condition. Its difficult to opine with accuracy with limited information. It probably could be either a contact allergy, that is the most common scenario. Treatment with antihistamines may alter the morphology and it may become difficult to diagnose. So consult a dermatologist and he will diagnose it for you and start you on appropriate medications. In case you are not in immediate access to a Dermatologist, you may consider taking a OTC antiallergic medications for relief. Best wishes Dr MK Agarwala New Delhi