Tinea versicolor, clinically known as pityriasis versicolor, is a fungal skin rash caused by an overgrowth of a certain yeast ...

As the skin breaks down, it becomes vulnerable to infection. In addition, you may develop a yeast, bacterial, or fungal underarm rash with intertrigo. Keeping skin folds cool and dry can help with ...

Other causes of an armpit rash include a yeast infection, psoriasis, or seborrheic dermatitis. Rashes are pesky patches of irritated skin that can affect any part of your body, including your armpits.