How do I perform the allergy test correctly before using this permanent hair dye?

Every permanent hair color can trigger sensitivity, even if you have colored your hair before without issues. The manufacturer requires an allergy alert test 48 hours before each application. Mix a small amount of colorant and developer (in the same ratio as for full application) and apply a thin layer behind the ear or on the inner elbow using a cotton bud. Leave it uncovered for 48 hours without washing the area. If you notice any redness, itching, burning, swelling, or blistering — even mild — do not use the product. Wash the test area immediately and consult a pharmacist or doctor if symptoms persist. This test must be repeated before every coloring session because sensitivity can develop at any time.

Practical tip: schedule the test when you can leave the area undisturbed for two full days — avoid swimming, heavy sweating, or applying other products to that spot. If you have a history of reactions to hair dyes, tattoos, or paraphenylenediamine (PPD), discuss with a dermatologist before proceeding.