Safety & Health Assessment & Research for Prevention (SHARP) — Research for Safe Work

Reprinted with permission from the American Academy of Dermatology. All rights reserved. Please note that the slides are very large JPEG files that will take up to 6.5 minutes to view or download using a 28.8 kbps modem.

Contact Urticaria or Pharmacologic Injury

Urticaria (hives) develops with contact of the plant or plant material. The reaction can be allergic or non-allergic. In the non‑allergic type reaction, irritant hairs on the surface of the plant enhance penetration of the pharmacological materials into the skin. These chemicals include acetylcholine, histamine and serotonin. The reaction can last for a few hours.

The allergic type reaction can result in swelling of the mucous membranes (eyes, lips and throat) with generalized urticaria. Individuals with atopic dermatitis are more prone to this type of reaction. Most of these reactions are caused by latex proteins, garlic, onions, tulips and lilies in susceptible people.

Slide 46

The stinging nettles (Urtica dioica) plant causes immediate burning and itching with contact. The reaction persists for a few hours. There may not be visible urticaria.

Return to Phytodermatitis Index or Dermatitis Educational Material.

Slide 47

Immediate urticaria can develop in persons who are allergic to the latex proteins in gloves. Latex comes from the sap of the Hevea brasiliensis tree.

Return to Phytodermatitis Index or Dermatitis Educational Material.