Itching on hip skin portion. Basis.

Sir, my wife is having itching skin issue on hip area. she is getting small pimples like on her hip skin coz of that. it keeps irritating till she itches. issue was there from past 7 years on minimal basis. it was seasonal before and was coming during summer. since from 2.5 years we have moved to costal area the problem is persistent. it keeps on coming now and then regular basis. coz of itching some portion of hips has become very dark and  have reddish pimples. till now it's on one side but we r afraid it may spread to other side as well and including near thighs. she is having allergenic to pencilin content medicines. and she is undergoing thyroid treatment by taking 50mcg tab daily. nothing else apart from that. she is not having any serious health issues and normal from past 3-4 years. appreciate a positive reply. thanks