Patch tests (epicutaneous tests)

What it is

They involve applying allergens to the skin under occlusive dressings in order to observe a delayed local inflammatory reaction.

Your care

• A specialist diagnostic investigation.
• Carried out as part of an allergy or dermatology work-up.
• Indicated when allergic contact dermatitis is suspected.
• Covered according to the applicable medical framework.

Where does the test take place?

👉 At the practice, under specialist supervision.

You go home with the patches in place and come back for the readings.

What is the test for?

Patch tests identify a delayed contact allergy, which causes skin reactions that appear several hours or days after exposure.

They cover, in particular:

• Metals (nickel, chromium, cobalt)
• Fragrances and preservatives
• Cosmetics and toiletries
• Products used at work
• Medicines applied to the skin
• Glues, resins, rubber

Indications

• Chronic or recurrent eczema
• Occupational contact dermatitis
• Reactions to cosmetics, fragrances or creams
• Metal allergies (nickel, chromium, cobalt…)
• Eczema of the hands, face or eyelids
• Suspected allergy to topical medicines

What happens

1. The allergen patches are applied to your back.
2. They stay in place for 48 hours.
3. First reading at 48 hours (Day 2).
4. Second reading at 72–96 hours (Days 3–4).
5. Medical interpretation and a detailed explanation.

⚠ Important: your back must stay dry, with no exercise and no showering during the testing period.

Results

• Delayed results.
• Positive reaction = redness, infiltration, localised blisters.
• Readings follow a standardised international scale.
• Results are given to you and explained, together with a personalised list of substances to avoid.

Safety

• ✔ A safe test.
• ✔ Reactions are limited to the skin.
• ✔ No systemic risk.
• ✔ Carried out under medical supervision.