This thesis explores the role of cosmetic products in causing Allergic Contact Dermatitis (ACD), a delayed-type hypersensitivity reaction mediated by T lymphocytes. It emphasizes the increasing prevalence of cosmetic-induced sensitization, particularly to substances like fragrances, preservatives (formaldehyde releasers, isothiazolinones), and newer compounds like Euxyl K400.

The study highlights the importance of patch testing as a diagnostic tool to distinguish ACD from Irritant Contact Dermatitis (ICD), a non-immune condition with similar symptoms. Clinical images and case examples illustrate the range of skin reactions encountered.

The thesis underlines the need for greater awareness, accurate labeling, and regulatory oversight in cosmetic formulations, and proposes prevention strategies such as patient education, safer ingredient selection, and early diagnosis to reduce the public health burden of ACD.