A common, seasonal, allergic contact dermatitis caused by toxic plants. It may be acute or chronic depending on the extent of the exposure and the degree of sensitivity to the allergens. Itching and vesiculation usually occur. The toxic agent in these plants is called urushiol , which is distributed widely in the roots, stems, leaves and fruit, but not in the flowers, pollen or epidermis. The rash usually occurs within two or three days after contact with the plant and disappears after 14 to 20 days.
Dermatitis duration depends on degree of sensitivity and frequency of re-exposure to the allergen.
Linear streaking is common and occurs naturally as the result of brushing the skin against the oozing sap of the poisonous plant. A term used to describe the topical reactions caused by exposure to toxic plants. In the U.S., poison ivy and poison oak are the main causes of rhus dermatitis. Found in the elderly patient, it affects the scalp, shoulders and legs. This dry, cracked, scaly skin is caused by the low humidity in heated homes and the low humidity of the outside air in winter months.