Allergic Contact Dermatitis of the Scalp: A Review of an Underdiagnosed Entity

The review discusses allergic contact dermatitis (ACD) of the scalp, an underdiagnosed condition that mainly affects women due to allergens in hair products and accessories. Symptoms like hair thinning and loss are often misdiagnosed, necessitating trichoscopic examination for accurate diagnosis. Common allergens include paraphenylenediamine in hair dyes and nickel in accessories. The review stresses the importance of patient-specific products in patch testing, as standardized tests may miss allergens. In women with alopecia areata, inflammation from these allergens can sometimes promote hair regrowth. Effective management includes avoiding allergens and using topical steroids, with systemic treatments for severe cases.