[Allergies to cosmetics].

The protean clinical delayed hypersensitivity reactions or the less common immediate hypersensitivity reactions can raise major diagnostic challenges, particularly as sensitisation can occur directly, indirectly or from a distance, with the allergen being handborne, airborne, or transmitted vicariously. Identification of the offending allergen among the vast array of potential candidates requires an exhaustive evaluation. The most common offenders are fragrances, which are ubiquitous, being found in a host of known or occult sources preservatives, hair dyes, excipient component, formaldehyde resins, and acrylic resins.