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A history of allergies or atopic dermatitis (eczema) increases the likelihood of allergic contact dermatitis (ACD). Irritant contact dermatitis (ICD) is not caused by allergies. However, many of the irritants that cause ICD can be allergens (substances that trigger an exaggerated immune system response) that trigger ACD in sensitive people.

Some of the irritants that are responsible for causing contact dermatitis are common items many people use regularly. For example, nickel, a common irritant, can easily come into contact with the skin through metal jewelry, zippers, buckles and buttons. Cosmetics – particularly hair dyes – may contain a substance known as paraphenylenediamine (PPD) that causes contact dermatitis in many people. Perfumes often contain preservatives or fragrances that irritate the skin. Poison ivy, oak and sumac are common irritants often encountered outdoors. When touched, the oil in these plants often causes itchy bumps to form on the skin.

Other common irritants and allergens related to contact dermatitis include:

• Adhesives
• Contact lens solutions containing mercury
• Deodorant
• Detergents and soaps
• Drool
• Fabrics and clothing
• Fiberglass
• Food additives
• Foods, particularly those high in nickel, such as fish
• Fruit, especially its peels
• Hair straighteners
• Insecticide
• Jewelry containing cobalt, nickel and other metals
• Latex found in gloves, rubber clothing and condoms
• Leather shoes treated with potassium dichromate
• Medications, particularly topical antibiotics or anesthetics
• Nail polish and nail polish remover
• Pesticides
• Preservatives (e.g., formaldehyde)
• Ragweed pollen
• Rubber
• Solvents
• Sunscreens that contain fragrances and preservatives