Allergy and Dermatology working together
Unify Health offers patch testing through collaboration between our Allergy and Dermatology teams.
Purpose
Patch testing checks for delayed contact allergy: an immune reaction to something touching the skin. It can help investigate recurring eczema or dermatitis linked to metals, fragrances, preservatives, rubber chemicals or personal-care products. Results guide allergen avoidance and treatment. It does not diagnose immediate food allergies and differs from skin-prick testing.
The process
- Your clinician reviews your history and selects substances to test.
- Small amounts are placed in chambers taped to your back, usually for about 48 hours.
- You return for removal and readings over several days, sometimes with a later check. The team confirms your appointment schedule.
- Your clinician interprets reactions alongside your history and explains relevant triggers and next steps.
Preparation
- Bring your medication list and relevant product ingredient labels; ask before bringing samples.
- Tell the team about pregnancy, breastfeeding, an active back rash, recent sun exposure or phototherapy, and steroid or immune-suppressing treatments. Testing may need rescheduling.
- Ask when to avoid medicated creams on the test area. Arrive without creams or lotions on your back.
- Antihistamines usually can continue for patch testing, unlike some skin-prick tests. Follow your specific instructions, particularly if both tests are planned. Do not change prescribed medication without advice.
Restrictions during testing
- Keep patches and skin markings dry until the team permits washing; avoid swimming and wetting your back.
- Avoid heavy sweating, strenuous exercise, friction, scratching and sun exposure to the test area.
- Wear loose, older clothing: ink can stain. Do not remove patches or apply products to the area unless instructed.
- Attend every reading. Contact the clinic if patches loosen or you develop significant discomfort; photograph and report delayed reactions.
Temporary itching or redness can occur; stronger reactions may blister. Your team will provide individual preparation and aftercare instructions.
Patient information: British Association of Dermatologists and American Academy of Dermatology.
