Hives that get worse with heat: what to know

Warm rooms, hot showers, exercise, fever, tight clothing, and emotional strain can all raise body temperature. Small itchy bumps after sweating may fit a heat-sensitive pattern, while larger migrating welts fit urticaria. Deeper swelling can occur with angioedema. See [Hives](/conditions/urticaria/), [Itchy Skin](/symptoms/itchy-skin/), and [Skin Swelling](/symptoms/skin-swelling/) for related information.

Move into a cooler space, loosen clothing, drink fluids, and use a cool—not icy—compress. Choose lukewarm showers, breathable fabrics, and gentle skin products. Pause strenuous activity while symptoms are active and note heat, sweat, pressure, foods, medicines, and timing in a diary. A clinician may discuss [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/) if episodes continue.

Seek emergency help for breathing difficulty, wheezing, faintness, or swelling of the lips, tongue, or throat. Arrange prompt review when heat-triggered episodes repeatedly interrupt activity, occur with fever, or leave bruising or pain. A clinician can check whether the eruption is hives or another [Skin Rash](/symptoms/skin-rash/) condition.

Does heat or sweating appear to be the trigger? Should I change exercise or bathing habits? Which antihistamine is suitable, and what symptoms mean I need emergency help?