What is the primary purpose of a patch test before a full color service?

• A. Identify sensitivities before full application
• B. Decide color shade
• C. Check processing time
• D. Evaluate hair elasticity

Answer: (A)

Seeing a patch test before a full color service is about safety: it screens for sensitivities to the dye ingredients so you can spot an allergic reaction before the product is applied everywhere. A tiny amount of dye is placed on a discreet skin area and checked over 24 to 48 hours for signs like redness, itching, or swelling. If any reaction appears, the service should not proceed to prevent a larger, more uncomfortable reaction. This is especially important for ingredients like PPD and other additives, and for first-time color clients or anyone with a history of allergies. The patch test doesn’t decide which color to use, nor does it assess processing time or hair elasticity; shade selection comes from consultation and swatches, processing time depends on the formula, and elasticity is tested separately.