Poison ivy hives: what to know

Hives are temporary, raised welts that can appear in different places and change shape. Poison ivy oil more often causes contact dermatitis: an itchy rash, redness, and sometimes fluid-filled blisters where the oil touched the skin. Scratching does not spread the plant oil, but unwashed clothing, tools, pets, or skin can transfer it.

Hives and deeper facial or lip swelling can occur as part of an allergic reaction. See the related guide to [Hives](/conditions/urticaria/) or [Angioedema](/conditions/angioedema/) if the pattern is unclear.

Rinse exposed skin promptly with plenty of water and a mild cleanser, then wash clothing, shoes, tools, and pet fur that may carry plant oil. Use cool wet compresses, avoid heat, and keep nails short. A pharmacist or clinician can advise whether [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/) fits your symptoms; do not use a medicine that is unsuitable for your age, pregnancy, or other conditions.

Get emergency help for trouble breathing, throat tightness, faintness, or rapidly worsening swelling of the lips, tongue, face, or throat. Arrange prompt medical assessment when the rash involves the eyes, mouth, or genitals, covers a large area, becomes increasingly painful, or develops pus, warmth, or fever. Severe reactions may need clinician-directed [Oral Corticosteroid Treatment](/treatments/medical-dermatology/oral-corticosteroid-therapy/).

Ask: Does this look like hives, contact dermatitis, or another [Skin Rash](/symptoms/skin-rash/)? Could my facial puffiness be [Skin Swelling](/symptoms/skin-swelling/), and which treatment is safe with my medicines? What should I do if [Itchy Skin](/symptoms/itchy-skin/) continues after washing?