What is contact dermatitis?
Contact dermatitis is a physiological reaction that occurs after skin comes in contact with certain substances. The majority of these reactions are caused by irritants to the skin. The remaining reactions are caused by allergens, which trigger an allergic response. In allergic reactions, the reaction may not start until after several days. Contact dermatitis caused by an irritant that is not an allergic response occurs from direct contact with the irritant. Adults are most commonly affected by allergic contact dermatitis, but it can affect persons of all ages.
Contact dermatitis is an eczematous skin disease which is caused by direct contact with a noxious agent. Most contact dermatitis reactions are dose related. The severity of the reaction depends on how long, how much and how irritating a particular substance is. Contact dermatitis is categorized into tow categories…irritant and allergic dermatitis. Irritant contact dermatitis, is more common and occurs immediately after exposure to a specific compound (e.g. solvents or detergents). Allergic contact dermatitis requires 24 to 48 hours before the skin rash develops. The most common contact allergen is nickel. Costume jewelry, watch faces and gold earrings, all of which contain nickel, can cause this type of reaction to occur. Fig. 1 Contact Dermatitis – due to an allergen. In this area a watch could be the culprit HOW DO I RECOGNIZE A CONTACT DERMATITIS REACTION? Contact dermatitis usually presents as an itching, red rash which may be associated with blister formation. Skin can be easily
Occupationally related contact dermatitis can develop from frequent and repeated use of hand hygiene products, exposure to chemicals, and glove use. Contact dermatitis is classified as either irritant or allergic. Irritant contact dermatitis is common, nonallergic, and develops as dry, itchy, irritated areas on the skin around the area of contact. By comparison, allergic contact dermatitis (type IV hypersensitivity) can result from exposure to accelerators and other chemicals used in the manufacture of rubber gloves as well as from exposure to other chemicals found in the dental practice setting. Allergic contact dermatitis often manifests as a rash beginning hours after contact and, like irritant dermatitis, is usually confined to the areas of contact.
Many of us experience contact dermatitis after encountering one of the unholy trinity of plants– poison ivy, poison oak or poison sumac. Oils from these plants make direct contact with the skin and cause a chemical irritation. Medical professionals call this Irritant Contact Dermatitis, or ICD. Other causes of irritant contact dermatitis can be soaps, detergents, hair dyes, foods, cleaning agents or pesticides. Irritant contact dermatitis accounts for up to 80% of reported cases. The other 20% of contact dermatitis cases stem from allergic reactions, especially ones developed over time. Accordingly, this form of the disease is called Allergic Contact Dermatitis, or ACD. Instead of an external irritant causing a direct reaction with the skin, allergic contact dermatitis is caused by the body’s own immune system. If a person is considered hypersensitive to nickel, for example, a rash may form directly under a nickel-plated bracelet. A hairdresser may form a sensitivity to certain hair d
