Definition: When psoriasis appears in the folds of skin under arms, under breasts or in the groin, it takes on a moist and red appearance. This form of psoriasis is called inverse psoriasis. It is easy to confuse with other common rashes of the intertriginous (skin fold) zones such as Candida (yeast), fungus, or seborrheic dermatitis. It is sometimes useful to look for more tell-tale signs of psoriasis like nail pitting or scaly red plaques on the elbows and knees when trying to diagnosis an intertriginous rash as psoriasis or not. Yeast can often be seen under the microscope in cases of Candidiasis using a simple test called a "KOH prep" test: Some scales or debris from the area in question are scraped onto a glass slide and soaked in potassium hydroxide solution. The skin scales melt away leaving yeast behind. Your dermatologist should be able to easily differentiate between these many conditions with a good exam and simple testing.
Also Known As: flexural psoriasis