What should you know about puppy hives?

Hives, or urticaria, may appear suddenly as pink or pale bumps and plaques that change shape or location. Triggers can include an insect sting, food, medicine, vaccine, contact exposure, or infection. Hives are different from a fixed scaly rash, although scratching can make the skin look more irritated. Swelling beneath the skin, called angioedema, may affect the face, lips, eyelids, or ears.

Remove the puppy from a suspected new food, shampoo, plant, or other exposure, but do not give human medicine unless a veterinarian directs you. Take a photograph and note when the welts began, what the puppy ate or contacted, and any recent medicine or vaccination. A veterinarian may recommend an age- and weight-appropriate antihistamine or another treatment after examining the puppy.

Seek emergency veterinary care for trouble breathing, repeated vomiting, collapse, marked weakness, pale gums, or swelling of the tongue, throat, or face. Even when breathing is normal, contact a veterinarian promptly because allergic swelling can change after the first welts appear.

Ask what trigger is most plausible, whether a medicine is safe for this puppy’s age and weight, which signs require emergency care, and whether observation or follow-up is needed.