Aalto-Korte K., Lauerma A. & Alanko K.
Occupational allergic contact dermatitis from lichens in present-day Finland
Lichens are abundant in forests, living on trees, soil, stones and rocks. They contain usnic acid and
other lichen acids that are contact allergens. Lichens and liverworts cause woodcutter’s dermatitis,
eczema that appears in the forest on the bare skin areas, especially in cold and wet weather.
Occupational allergic contact dermatitis from lichens occurs in forestry and horticultural workers
and in lichen pickers. Lichens can cause immediate allergy, contact urticaria, rhinitis and asthma …