A wide range of plants may cause allergic eczema when touched.
The most important sources in Denmark are:
Plants from the sun flower family (Compositae or Asteraceae)
Primula (Primula obconica)
The sun flower family is one of the largest plant families in the world. It includes many well-known cultivated plants like chrysanthemum, sunflower, marigold, calendula and daisies, but also weeds such as dandelion, bellis, chamomile and tanacetum.
Among edible plants in the family are lettuce, artichokes and tarragon. Many sun flower species have been used since ancient times as medicinal plants, and especially chamomile, arnica and marigold are still used frequently in herbal medicine and cosmetics.
It usually requires prolonged exposure to a plant to develop an allergic reaction to it. Therefore, gardeners and florists are particularly vulnerable. But even chefs and sandwich makers can develop plant allergy through their contact with for example vegetables from the sun flower family.
In Denmark, we see frequent allergy to plants from the sun flower familiy in hobby gardeners who for years have cared for their garden with chrysanthemums and daisies in the herbaceous border or in individuals who frequently pick dandelions or lettuce leaves for pets.