17:46 24.06.2024

Patch test — effective allergy diagnostics at "ON Clinic Odesa"

4 min read


A patch test (application skin test) is a test that is performed to diagnose various forms of allergy, regardless of the patient's age and the location of the rash. During one test, you can check for reactions to 10-30 allergens. Patch test in Odesa is performed at the medical center "ON Clinic Odesa". Appointments for patch test are made around the clock (via the website or by phone).


Types of patch test in the medical center "ON Clinic Odesa"

A patch test may be prescribed in case of suspected allergic dermatitis. Other indications for patch testing include:

  • contact allergy;
  • polymorphic erythema;
  • coin-shaped (numular) eczema;
  • neurodermatitis;
  • tinea versicolor.

Patch testing is also performed in case of inflammation of the mucous membranes (for example, conjunctivitis, stomatitis or vulvitis). An additional indication for allergy screening is psoriasis.

During one visit to the medical center, you can perform a patch test for 10, 20 or 30 allergens. Types of patch tests:

  1. Atopic-10 (test for 10 allergens).
  2. Atopic-20 (test for 20 allergens).
  3. European (testing for 30 basic allergens that are most common on the European continent).

The type of test is chosen by the dermatologist after examining the patient (for example, patch tests for metals or medications can be performed). Patch testing should not be performed in severe dermatitis and injuries to the skin areas to be applied. Conditional contraindications to patch testing are pregnancy and breastfeeding.

Preparing for the patch test

One of the stages of preparation for an allergy test is to stop taking antihistamines (three to seven days before the test), antidepressants (10 days before the test), and corticosteroids (two weeks before the test). Preparation for the patch test also includes:

  • examination, medical history;
  • refusal to sunbathe, use tanning lamps or visit a solarium for two weeks;
  • hair removal in the area of testing;
  • stop using skin care products (in the testing area) on the day of the appointment;
  • wearing short-sleeved or sleeveless clothes at the appointment.

The optimal place to place the patches is the upper back. It is also allowed to apply them on the outer sides of the shoulders or thighs. Placing the patches on other areas of the skin may increase the risk of false-negative results.

How is allergy patch testing performed?

The patch test is performed by an allergist. Stages of an allergy patch test:

  1. Cleansing the skin, which is characterized by increased fat content, with ethyl alcohol.
  2. Shaving or trimming hair on the skin area where the patch is to be applied (in case of abundant hair).
  3. Fixing the patch test systems filled with haptens on the skin of the patient's upper back (the allergy test is not performed on the spinal line of the back, the shoulder blades, and in women — on the shoulder line of the bra).
  4. Marking the first and fifth cells of each patch with a special marker.

The patches should remain attached to the patient's skin for 48 hours. Until the patches are removed, vigorous exercise, water procedures, and direct sunlight on the back should be avoided. In addition, it is necessary to stop taking glucocorticosteroids and other medications that may affect the state of the immune system.

Evaluation of the results of the application skin test

On the second day (48 hours) after application, the patch test system is removed and the presence of allergy symptoms is checked. The main evaluation of the results is performed 48 hours after the patch test system is removed, i.e. on the fourth day after the start of allergy diagnostics. Most haptens appear on the fourth day, and some haptens - on the seventh day from the start of testing.

A positive skin test indicates an allergy to certain substances, which may be accompanied by itching or redness of the skin. A negative patch test is considered to mean that there is no allergy to the substances contained in the patches.

Skin allergy tests do not always provide one hundred percent accuracy, so the results may be false positive or false negative. After evaluating the results of the patch test, the allergist provides the patient with recommendations, which may include medication, immunotherapy, diet therapy, and organizational measures to avoid contact with allergens. If necessary, the doctor prescribes additional tests (e.g., blood test for allergens or ALEX test).

You can make an appointment for a dermatologist's consultation and patch test in Odesa by calling the phone number listed on the website of the medical center "ON Clinic Odesa" or through the appointment form, which is also available on the website.