Nickel is the most common allergen, though many other sources of contact allergens are hidden in everyday products, such as preservatives and fragrances. In screening for contact allergy, it is important to inquire about environmental and occupational exposures, including wet work and mechanisms of irritation, such as frequent hand washing or wiping. The mechanisms of contact dermatitis are complex and may involve different T cell signaling pathways. Patch testing is required for diagnosis, and patch testing with patient's personal products is recommended. Management currently focuses on allergen avoidance, topical therapies, or corticosteroids; some biologics may be indicated for treatment.