Hives on forearms: causes and next steps

Forearm welts can be pink, red, or close to your natural skin tone. They may appear after sun exposure, sweating, exercise, tight sleeves, plants, cosmetics, medicines, foods, or an infection. New welts can arise while earlier ones fade, so the overall rash may seem to travel. This pattern fits [Hives](/conditions/urticaria/), but a rash that remains in the same place, scales, cracks, forms blisters, or bruises may have another cause. Itching is common; see [Itchy Skin](/symptoms/itchy-skin/) for related symptoms. Swelling of the forearm, hands, lips, or face can occur with the reaction.

Move away from a suspected product or plant and change out of tight, warm clothing. Cool the forearms with a clean damp cloth, keep nails short, and pat rather than scratch. Avoid testing several new creams at once, since this can make the trigger harder to identify. Keep a simple record of exposure, activity, medicines, food, and how quickly the welts changed. Ask a pharmacist or clinician about [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/), especially if you take other medicines or have ongoing conditions.

Seek emergency help if hives occur with difficulty breathing, hoarseness, throat tightness, faintness, or swelling of the tongue or lips. Get prompt medical advice for rapidly increasing limb swelling, severe discomfort, or a flare after a medicine, food, or sting. Book a review if episodes recur, interfere with sleep, or do not behave like brief, migrating welts.

Could clothing, heat, or contact exposure explain the distribution? Should I stop any recent product or medicine? What should I keep in a symptom diary? Which warning signs mean emergency treatment?