What should you know about hives in armpits?

Hives, also called urticaria, result from chemicals released in the skin. Heat, sweating, friction, deodorant, a new medicine, an infection, or food can be associated with an episode, although a trigger is not always found. The folds of the armpits can make itching worse because moisture and rubbing irritate the area. Hives may be pink, red, or skin-coloured and often have a paler centre. They are different from a fixed rash that stays in one spot for days.

Swelling under the skin may occur around the armpit, lips, eyelids, or tongue. This deeper swelling is called angioedema and deserves particular attention when it affects the mouth or throat.

Move away from a suspected new product, rinse sweat from the skin with lukewarm water, and wear loose breathable clothing. A cool compress can reduce the urge to scratch. Photograph the welts and record recent foods, medicines, products, exercise, heat, and insect exposure; this helps a clinician look for patterns.

Do not start a medicine from someone else. A clinician or pharmacist can advise whether an oral antihistamine is suitable, especially for a child, pregnancy, chronic illness, or other medicines. Avoid scratching, tight clothing, and fragranced products while the skin settles.

Get emergency help immediately for trouble breathing, wheezing, throat tightness, difficulty swallowing, faintness, or rapidly increasing swelling of the lips, tongue, or face. These symptoms can signal a serious allergic reaction, even if the skin welts seem mild.

Arrange medical advice if hives keep returning, cover much of the body, follow a new medicine, or do not settle. A fixed, painful, bruised-looking, blistering, or fever-associated rash needs assessment because it may not be ordinary hives.

Ask: Could this be hives rather than contact irritation or infection? Which products or medicines should I pause? Is an antihistamine appropriate for me, and what symptoms mean I should seek emergency help?