Symptoms
After brief contact with an appropriate plant, e.g., during gardening or play and exposure to sunlight, a skin rash forms with a delay within 1-4 days. It manifests itself in severe reddening of the skin with the formation of vesicles and blisters at the sites of contact and, depending on the contact with the plant, is distributed over the skin in bizarre stripes and streaks. The redness is accompanied by an annoying itching, swelling and burning pain. The lesions heal within a few weeks. This often results in a dark hyperpigmentation that persists for a long time.
Cause
This is a phototoxic skin disorder caused by a reaction of plant ingredients with UV radiation. Since there is no underlying allergy, meadow grass dermatitis can develop in any person. It is favored by moist skin. The increased sensitivity to the sun can last for several days, depending on the plant or substance. Thus, upon re-exposure to the sun, another skin reaction may occur. The sensitizing substances are often furanocoumarins (psoralens) such as bergapten, xanthotoxin, limettin and isopimpinellin. These substances are found in the following plants, for example: Parsnip, Hercules Perennial, Hemlock, Masterwort, Angelica, Figwort, Garden Rue, Bergamot, Amenning, Knotted Carrot, Celery, and Dill. Photosensitivity is also possible when the plants are consumed as food. Skin contact with furanocoumarins may also cause a reaction or allergic contact dermatitis. This has been shown, for example, for the fig tree.
Complications
Superinfections may develop because of damage to the skin barrier. Skin pigmentation may persist for months and be cosmetically disruptive.
Prevention
Contact with the relevant plants should be avoided. For this purpose, clothing and gloves should be worn when gardening.
Treatment
Severe meadow grass dermatitis should be treated like a second-degree burn by a physician. This involves sterile puncturing of larger blisters, cleaning, disinfection, and protection with a dressing. The redness of the skin can be cooled like a sunburn and treated with mild and cooling skin care products. For symptomatic treatment of pain and inflammation, nonsteroidal anti-inflammatory drugs such as ibuprofen or glucocorticoids may be appropriate.