How is allergen testing?

Not all pt need PT, only if unclear allergen or chronic dermatitis it is needed, positive test is considered only if the rash is gone after removal of allergen. Allergens causing ACD (nickel (most common), chromates (leather, cement), rubber accelerators, fragrances, preservatives, hair dye, cocoamidopropyl betaine, meds (topical) Read positive test at 96 hours, to improve rash avoidance of allergens is required 1-3% of population are allergic to cosmetics ingredients