Allergic contact dermatitis

Allergic contact dermatitis (ACD) is a cutaneous inflammatory disease very frequent in developed countries, therefore representing an issue of great impact in terms of public health. A large array of agents is responsible of DAC, including metals, cosmetics, dyes, fragrances, and drugs. DAC is sustained by a cell-mediated, delayed hypersensitivity mechanism. The clinical and morphologic features of point of ACD are characterized by eruptive polymorphism (multiple different lesions occurring simultaneously) as well as evolutive polymorphism (lesions changing over time), itching representing the pivotal subjective symptom. Diagnosis of ACD relies on patient history (assessing patient lifestyle, habits, hobbies, use of clothing and accessories, personal hygiene products, cosmetics and household detergents), clinico-morphological features and allergy testing, including patch tests and provocative use tests. The main objective of ACD therapy is to mitigate the acute phase inflammation, to oppose the subacute and chronic phases xerosis and to improve pruritus, which is present in all three phases. Most used therapeutic agents are sodium hypochlorite wet compresses, 1% phenicated fuchsin and 1% gentian violet stains in acute exudative phase, while subacute and chronic ACD benefit from systemic antihistamines and from alternated use of topical corticosteroids and emollients/moisturizers. Oral corticosteroids or systemic immunosuppressants are indicated in diffuse, erythrodermic and non-responsive ACD forms. Indeed, the major factor in the management is the avoidance of the offending agent(s) and the adoption of appropriate preventive measures