Symptoms
Allergic contact dermatitis is a noninfectious skin disorder that begins with a delay of one to three days after allergen exposure, with redness of the skin, the formation of poplars, oedemas, and vesicles. The severe itching that accompanies the reaction is typical. The vesicles burst and weep. The skin reaction may also spread to nearby or distant skin regions that have not been in contact with the allergen. As the disease progresses, repeated exposure to the allergen may result in chronic skin disease with redness, vesicles, scaling, skin cracking, dry and thickened skin. Possible complications include superinfection of the skin lesions, chronicity of the disease, and depending on the allergy, it may be necessary to change jobs.
Causes
Allergic contact dermatitis is a type IV (late-type) cell-mediated allergy triggered by contact allergens. These are low-molecular-weight molecules (haptens) or metal ions that become the actual allergen only when combined with a protein in the skin. The prerequisite is an existing hypersensitivity to the corresponding allergen. A selection of common contact allergens:
- Nickel, cobalt, chromium, e.g. in piercings, earrings, jewelry.
- Wool wax is a component of skin care products and lip balms.
- Peru balsam
- Paraphenylenediamine, e.g. in hair dyes.
- Potassium dichromate, e.g. in leather
- Bufexamac
- Parabens
- Cosmetics, toiletries, preservatives, perfume.
- Clothing, e.g. zipper
- Food
- Numerous other allergens are considered as triggers.
Diagnosis
The diagnosis should be made in medical treatment at the dermatologist. The medical history and localization often give good clues (occupation, hobbies, jewelry, jeans button, watches, piercing). An epicutaneous test can identify the contact allergens. Numerous other skin diseases that produce a similar clinical picture must be excluded in the diagnosis.
Nonpharmacologic treatment
The most important measure is avoidance of the relevant allergens. In the worst case, this may even mean changing occupations (e.g., hairdressers). Avoiding the allergens allows healing and prevents a chronic course.
Drug treatment
Topical glucocorticoids:
- When applied locally, are usually the first-line agent. They have anti-inflammatory, antiallergic, and indirect antipruritic effects and, except for hydrocortisone, must be prescribed by a physician. In severe cases, oral glucocorticoids are also prescribed.
Skin care products:
Wound dressings:
- Protect the lesions and promote wound healing.
Antihistamines:
- And other remedies for itching can be used in self-medication against the itching and allergy. There are also many alternative medicines on the market such as cardiosperm ointments.
Immunosuppressants:
- In severe, refractory or chronic course, immunosuppressants and PUVA treatment are also used.
- The retinoid alitretinoin is approved as a 2nd-line agent for the treatment of chronic hand eczema.
In treatment, it is important to note that the drugs do not contain precisely those allergens that cause allergy in patients. For example, perubalsam sticks are popularly used against chapped skin and should of course be avoided if the patient has a corresponding allergy. Topical glucocorticoids (! ), antibiotics and ointments with asteracea extracts can also cause allergy. The anti-inflammatory bufexamac, which was frequently used for the local treatment of eczema in Germany, for example, is itself a strong contact allergen and has since been withdrawn from the market (see under Bufexamac).
