Diagnosing allergic contact dermatitis is important because allergic contact dermatitis can scratch us in different ways. Sometimes contact dermatitis (contact allergy) is easy to recognize and can be diagnosed without much testing. Sometimes, it is difficult to diagnose that skin reactions or aphthae that do not heal in the mouth, widespread itching in the body, are due to allergic contact dermatitis, and many unnecessary tests can be performed.

In order to diagnose allergic diseases, the patient’s history must be taken carefully. In allergic contact dermatitis, the patient’s history and complaints are extremely important for diagnosis. A very good history should be taken, including information about the work environment, hobbies, products used at home and at work, and sun exposure, plus the date between chemical exposure and the appearance of symptoms will increase your chances of making a diagnosis. If there is a skin rash in the form of redness, crusting, itching, it usually (but not always) indicates that the allergen is in contact with the skin. However, it can sometimes occur days after contact with the allergen.

Diagnosis of Allergic Contact Dermatitis

The most important diagnostic method of allergic contact dermatitis is skin patch test. The mainstay of diagnosis in allergic contact dermatitis is patch testing. The skin patch test has a sensitivity and specificity of 70% to 80%.

The skin patch test is the gold standard for confirming the diagnosis in patients with suspected allergic contact dermatitis.

It is especially suitable for patients with certain complaints. These situations can be listed as follows.

Those who have chronic eczema or similar skin rash on their body,

In addition to the personal products used, if other contact allergens at home and at work are suspected,

Especially in patients presenting with hand dermatitis or anatomically localized skin rashes (such as face, eyelids),

In a patient with reddening of the entire face, including the face or the area around the eyes (e.g. eyelids),

In patients presenting with lip dermatitis (cheilitis) or dermatitis around the mouth

In patients with recurrent oral mucosal inflammatory wounds,

In patients presenting with dermatitis involving the scalp and neck; cosmetics, hair products and jewelry are among the most common causes of contact dermatitis.

In all patients presenting with acute or chronic hand eczema:

In patients with axillary dermatitis due to allergens in deodorant substances and topically applied products in textiles; sometimes axillary dermatitis may be a manifestation of diffuse systemic contact dermatitis.

In patients presenting with anogenital dermatitis; depending on topically applied creams.

It may occur following systemic exposure to an allergen causing a known contact dermatitis in a patient with diffuse, thoracic dermatitis.

In patients presenting with unexplained chronic dermatitis of the lower extremities, feet and/or soles; rubber chemicals, adhesives, and components in shoe leather may be responsible.

Skin patch testing should be performed if suspected in patients with atopic dermatitis (AD).

Allergic contact dermatitis can sometimes occur with the application of prosthesis and filling materials to the body. Especially after dental fillings or orthopedic prostheses, it can cause non-healing wounds in the mouth or prosthesis site.

There are studies showing that in some patients, stents placed in the heart vessels may cause myocardial infarction due to occlusion.

Therefore, before the procedure is performed in patients, it is absolutely necessary to perform a patch test against the substances to be used with the skin patch test. Otherwise, non-healing wounds or allergic contact dermatitis complaints may occur after a successful procedure.

The patch test allows people who have become sensitive to a certain allergen to see the reactions that occur on their skin when they come into contact with the allergen. It enables the chemical substance that causes allergic contact dermatitis to be found in a person. Usually the back is used for convenience. Allergens are placed sequentially and then adhered to the patient’s back. The optimum timing of readings for skin patch tests is likely between 2 days and 3 days. Sometimes an additional reading on days 6 or 7 can be about 10% more positive response, negative on days 2 and 4. The most common allergens that can become positive after day 4 are neomycin, tixocortol pivalate and nickel.

The open patch test is another frequently used test when evaluating potential irritants or allergens that cause allergen contact dermatitis. It is also useful in the investigation of contact urticaria and allergic contact dermatitis. The open patch test is usually done on the forearm, but the upper outer arm or scapular areas may also be used.

An open application test is used to confirm contact allergy to cosmetics such as a moisturizer. The suspicious product is applied to the inner part of the upper arm or other areas, then it should be evaluated at regular intervals during the first 30-60 minutes and the next evaluation should be made after 3-4 days. Usually, the product needs to be applied twice a day for up to a week, depending on whether a reaction develops. While cosmetic contact urticaria develops immediately, allergic contact dermatitis may occur later.

Blood tests used to diagnose chemicals that cause allergic contact dermatitis may also be helpful. Lymphocyte transformation tests showing delayed reaction can be used to diagnose. More studies are needed before these tests are routinely used.

How is the Treatment of Allergic Contact Dermatitis in Adults?

After the diagnosis of allergic contact dermatitis is made, the patient needs to make some changes in his work and home life for its treatment.

Treatment for allergic contact dermatitis mainly includes:

Once the allergen or irritant has been identified, the patient should avoid contact with the offending agent.

In addition to avoiding exposure, appropriate medical treatment should be prescribed to alleviate the patient’s complaints.

Avoiding exposure to irritants and allergens and using appropriate skin protection can be helpful to prevent contact dermatitis.

Along with the training of workers with contact dermatitis, changes in home and work life need to be made at the same time. Despite all this, patients should be informed that the disease may continue and that long-term treatment will be needed even after treatment and workplace renovation.

Prevention is very important in allergic contact dermatitis. But there is a need for drugs to be used to eliminate the complaints of the patients.

General treatments include: Oral and/or topical corticosteroids, antihistamines, lotions and creams.

Topical corticosteroids

Creams containing topical corticosteroids are widely accepted as a treatment for contact dermatitis. There are studies showing that the use of a combined topical corticosteroid/antibiotic combination 52 in infected or potentially infected eczema may be beneficial.

Topical tacrolimus has been shown to be effective in nickel allergic contact dermatitis.

Second-line treatments such as PUVA, azathioprine, and cyclosporine are used for steroid-resistant chronic hand dermatitis.

It is known that some nickel-sensitive patients have systemic common complaints with oral intake of nickel. There are studies supporting the benefit of low nickel diets in such patients.

Patients with allergic contact dermatitis:

In addition to avoiding contact with substances that cause skin rashes, washing the area in contact with allergic substances can reduce the occurrence of contact dermatitis.

In allergic contact dermatitis, the complaints can be improved by eliminating the contact with the allergen. Therefore, it is very important to detect the allergen that causes contact allergy.

Even if allergic contact dermatitis disappears with precautions in mild forms, unfortunately, it can continue in some of them despite the precautions. Early detection of allergens that cause allergic contact dermatitis with skin patch tests can prevent the occurrence of serious and permanent contact dermatitis that will occur later.