Contact Dermatitis

Contact dermatitis is a common inflammatory skin condition resulting from direct exposure to environmental irritants or allergens, manifesting as rash, itching, redness, swelling, and skin lesions. It comprises two primary forms: irritant contact dermatitis (ICD), caused by direct damage from exogenous agents such as acids, alkalis, detergents, and certain chemicals in hair dyes or nail polish removers, and allergic contact dermatitis (ACD), driven by immune responses involving cytokines and allergen-specific CD4+ and CD8+ T cells. Heavy metals like chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), gold (Au), cobalt (Co), palladium (Pd), and mercury (Hg) are significant contributors to both ACD and systemic contact dermatitis (SCD), particularly due to their widespread industrial use and potential for sensitization. These metals can induce localized or systemic reactions upon occupational or environmental exposure. Diagnosis relies on clinical evaluation and laboratory methods including patch testing, lymphocyte stimulation tests (LST), and cytokine profiling. This summary highlights the epidemiological and clinical features of ACD and SCD associated with Cr, Cu, and Pb, while also addressing the role of other heavy metals in contact hypersensitivity, excluding nickel due to recent comprehensive reviews.