Answer
Immunologic contact urticaria typically affects individuals who have a long history of handling food and/or atopy.
Celery (Apium graveolens) is the most common plant cause of generalized urticarial or anaphylactoid reactions. Within 30 minutes of contact with certain plants, pruritus, erythema, vesicles, and urticarial swelling may develop. Cooking, processing, deep-freezing, or crushing of fruits and vegetables generally reduces their allergenicity.
Protein contact dermatitis represents a chronic dermatitis in which patch testing results are typically negative; however, prick tests with large protein allergens usually causes positive results.
The most sensitive tests for immunologic contact dermatitis are the prick test and the scratch chamber test. Prevention is the key method of controlling this condition; however, the use of antihistamines can be helpful.
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Young poison ivy plant Toxicodendron radicans. The leaves of 3 are easily identified. Reprinted with permission from WB Saunders.
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Mature poison ivy Toxicodendron radicans. Fruit arises in an axillary position in the angle between the leaf and the branch.
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Mature gingko tree, Ginkgo biloba, growing in Frederick, Md.
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Ginkgo biloba has a characteristic bilobed leaf.
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Daisy flower, Leucanthemum species, with characteristic flower heads of the Asteraceae family.
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Finger of a florist with an eczematous plaque caused by sensitivity to tulipalin A, the allergen contained in Peruvian lilies (family Alstroemeria).
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Airborne contact dermatitis in a patient who is allergic to sesquiterpene lactones. The involvement of the anterior part of the neck seen here is typically absent in photodermatoses. Courtesy of Dirk Elston, MD.
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Irritant reaction on the scrotum after contact with garlic (Allium sativum). Courtesy of Martin Giandoni, MD. Reprinted with permission from Cutis 67: 193, 2001.
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Tulipa species (Liliaceae). Reprinted with permission from Cutis (2003;71:347-348). Copyright 2003, Quadrant HealthCom, Inc.
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The coverings of tulip bulbs can cause irritant contact dermatitis, and tulipalin A and B can cause allergic contact dermatitis. Reprinted with permission from Cutis (2003;71:347-348). Copyright 2003, Quadrant HealthCom, Inc.
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Alstroemeria ligtu (Alstroemeriaceae). Reprinted with permission from WB Saunders.
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Primula obconica
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Urtica dioica, the common stinging nettle.
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Prickly pears, Opuntia species.
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Dieffenbachia bauseii (Araceae), also known as dumb cane.
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Daffodils, Narcissus pseudonarcissus, are also known as Lent lilies because they bloom in late March and early April in much of the United States.
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Chili peppers, Capsicum annum.
