Compositae dermatitis.

Compositae dermatitis is an allergic contact dermatitis. The most important allergens in the Compositae family are sesquiterpene lactones (SL), which are present in the oleoresin fraction of leaf, stem, flower and possibly pollen. Compositae dermatitis is most frequently seen in middle-aged and elderly people in patterns reflecting airborne or direct contact with the allergens. The pattern typically starts in summer and disappears in the autumn or winter. Repeated exposure over many years may lead to a chronic and, at times, a disseminated pattern. Seasonal variation does not occur in occupational Compositae dermatitis. In addition to the classically described airborne pattern of face, 'V' of neck, hands and forearms, hand dermatitis is now recognized to be an equally common presentation. This variability of clinical features, and the frequent occurrence of atopic dermatitis and contact allergy to one or more compounds, highlights the need for routine patch testing with sesquiterpene lactone mix 0.1% (Thermal, Hamburg, Germany), combined with aimed patch testing with Compositae plants and extracts. Avoidance of the plants and plant extracts of this large family can be difficult due to its widespread occurrence in flower, herb and vegetable gardens, urban and rural weed population and native vegetation. Importantly, Compositae plant extracts are present in many cosmetics, shampoos, herbal creams and ingested herbal remedies and tonics.