Patch Test

What the Test Involves

Patch testing is non-invasive and painless, since allergens sit on the skin surface rather than being injected. You'll need multiple visits over several days:

• Application appointment: patches containing selected allergens (metals like nickel, fragrances, preservatives, cosmetic ingredients, rubber chemicals) are placed on clean, healthy skin on your upper back
• First reading (around 48 hours): patches are removed and each site is examined for redness, bumps or blisters
• Later reading (72–96 hours, sometimes day 7): delayed reactions are checked, since contact allergy is a slow immune response

During the wearing period you must keep the back area dry—no showers that soak the patches, swimming, saunas or vigorous exercise—and avoid applying any creams or perfumes over the test sites.

Who Should Consider Patch Testing

This test is designed for people with chronic or recurring dermatitis whose skin problems haven't responded well to standard treatment. It's especially useful if you suspect:

• Reactions to jewellery, cosmetics, fragrances or hair products
• Hand eczema linked to work exposures or household products
• Facial dermatitis from skincare or makeup
• Persistent rashes in areas that contact specific materials (clothing, shoes, rubber, adhesives)

Patch testing identifies delayed-type contact allergy; if you have immediate reactions (hives within minutes, breathing problems, food anaphylaxis), different allergy tests are needed.

After Your Results

A positive reaction—localized redness, swelling or blisters directly under an allergen—indicates sensitization to that substance. Your specialist will:

• Grade and interpret each reaction
• Explain which everyday products and environments contain the offending allergen
• Provide detailed avoidance strategies tailored to your lifestyle and occupation

There are no vaccines or cures for contact allergy, so long-term management relies on strict avoidance. Most people see significant improvement or resolution of their dermatitis once identified allergens are eliminated from daily life. Mild temporary discomfort at positive sites is normal, but any intense reactions should be reported promptly so they can be managed appropriately.