Flexural psoriasis (also called Inverse psoriasis or intertriginous psoriasis). This type of psoriasis develops in areas where skin touches skin, such as the armpit. Flexural psoriasis is characterized by smooth, red patches of skin that look raw. Patches only develop where skin touches skin, such as the armpits, around the groin, genitals, and buttocks. Women can develop a red, raw patch under their breasts. Skin feels very sore where inverse psoriasis appears.