Red rash under armpit: what should you know?

The armpit is warm and folded, so sweat and rubbing can soften the skin and encourage a rash. A new deodorant, antiperspirant, soap, detergent, or shaving product can trigger Contact Dermatitis. Heat Rash may cause small prickly bumps after sweating. Intertrigo tends to affect skin folds, while Ringworm can form a scaly or spreading edge. Itching in several household members can raise concern for Scabies. Atopic Dermatitis or Psoriasis can also affect the underarm, although their appearance varies.

Gently wash the area with lukewarm water and a fragrance-free cleanser, then pat it dry. Pause recently introduced scented products and avoid shaving or rubbing the rash until it settles. Wear loose, breathable clothing and change out of sweaty clothes. Do not scratch, squeeze, or share towels. A clinician or pharmacist can help choose treatment after checking whether the skin is mainly irritated, inflamed, or infected; avoid using a steroid or antifungal product blindly when the diagnosis is uncertain.

Arrange prompt medical care if the rash is rapidly spreading, hot, very painful, swollen, draining pus, or accompanied by fever. Seek urgent help for facial swelling, breathing difficulty, faintness, or a widespread rash after a medicine. Book an assessment if it keeps returning, interferes with sleep, involves broken skin, or does not start improving after removing an obvious irritant.

Ask which features point to irritation, Intertrigo, Ringworm, or another condition; whether a product or medicine could be involved; what treatment is suitable for the folded skin; and how to prevent recurrence during hot or humid weather.