Medically reviewed by Susan Bard, MD Some causes of underarm rash include infection, allergic reaction, and inflammation.

The best heat rash treatment methods include medicated creams ... especially if the area is blocked by tight clothing or skin folds. Important: Overall, heat rash is considered a benign condition ...

It causes small discolored or fluid-filled blisters to develop in the folds ... medical treatments like topical medications and phototherapy and avoiding triggers. Heat rash is a skin condition ...

Perioral dermatitis usually appears as a rash of pus-filled bumps around the mouth and in the folds ... perform a skin biopsy, especially if the rash doesn’t respond to standard treatments.

Red itchy skin Understand the difference between atopic dermatitis linked to allergies and general eczema with this ...

The rash can also be itchy. How to treat it: Topical antibiotics are usually the first course of treatment ... affects regions where there are skin folds –– including the armpits.