Contact Allergy

Synonyms

Allergic contact dermatitis; Contact hypersensitivity

Definition and Characteristics

Itchy skin reaction with erythema, edema and vesicles occurring at the site of penetration of chemicals in pre-sensitized individuals. In the chronic phase, increased epidermal thickness with scales and painful fissures are frequent.

Prevalence

Widely common disease in both professional and extraprofessional settings. Prevalence in general population varies dramatically depending on the source considered. It has been reported that 2-15% of individuals residing in industrialized countries are skin sensitized at least to one substance, but the general assumption is that prevalence is greatly underestimated.

Molecular and Systemic Pathophysiology

Contact allergy is the consequence of an unbalanced T cell immune reaction against small chemicals, named haptens, contacting the skin. In the sensitization process, the hapten penetrating the skin promotes the mobilization