Cat allergy hives: what to know

Hives may appear as pink, red, or skin-coloured bumps or patches that change shape or move to different areas. They can follow touching a cat, being in a room with cat dander, or contact with fabrics carrying allergen. A single welt often fades while new ones appear elsewhere. Hives are the condition presenting with itchy skin and a skin rash; the rash itself does not prove that cat allergy is the cause. Other triggers include infections, medicines, heat, pressure, and foods. Swelling around the lips, eyelids, tongue, or throat can occur with a deeper allergic swelling called angioedema.

Move away from the suspected exposure and avoid rubbing the skin. Wash hands and change clothing after contact, and keep the sleeping area free from items that hold cat dander. A cool compress and loose clothing may reduce irritation. A clinician or pharmacist can advise whether an oral antihistamine treatment is suitable, considering age, pregnancy, other medicines, and health conditions. Do not start oral corticosteroid treatment without medical advice. Take a photo if the appearance changes before an appointment, and record when exposure occurred and how quickly the welts developed.

Call emergency services immediately for trouble breathing, wheezing, throat tightness, faintness, confusion, or rapidly increasing swelling of the tongue or throat. Seek prompt medical care for swelling of the face or mouth, widespread hives, repeated episodes, or symptoms that do not settle after leaving the suspected trigger. A clinician can assess whether this is hives, another skin rash, or a different allergic problem.

Could this be hives rather than another skin rash? Should I use an antihistamine, and which one fits my medicines or health conditions? What signs would mean angioedema or an emergency? How can I reduce cat-allergen exposure at home?