<s>[INST] My wife and I both started antibiotic treatments in the past month for sinus infections. Both of us now have severe itching around beltline, buttocks and thighs. She itches under bra strap. At night my itching worsens. No visible rash, only a couple of small welts. What could be the cause? [/INST] HI, thanks for using Chat Doctor The itching may be due to fungal infection especially since it is the areas that are moist and may have friction. The two of you can consider the use of a topical antifungal creams and topical steroid creams. The topical steroid cream would help to reduce the inflammatory response. Examples of topical antifungal are Mizoram, console, miconazoleA topical steroid cream such as HY Chat Doctor. This medication may be obtained over the counter. I hope this helps </s>