Dermatitis

What causes Dermatitis?

Dermatitis is inflammation of the upper layers of the skin, causing itching, blisters, redness, swelling, and often oozing, scabbing, and scaling.

Dermatitis is a broad term covering many different disorders that all result in a red, itchy rash.  Some types of dermatitis affect only specific parts of the body, whereas others can occur anywhere.  Dermatitis is always the skin's way of reacting to severe dryness, scratching, an irritating substance, or an allergen.  Typically, that substance comes in direct contact with the skin, but sometimes the substance is swallowed.

Dermatitis may be a brief reaction to a substance.  In such cases it may produce symptoms, such as itching and redness, for just a few hours or for only a day or two.  Chronic dermatitis persists over a period of time.

The hands and arms are particularly vulnerable to chronic dermatitis, because the hands are in frequent contact with many substances such as oils, greasers or petrol/diesel at work.  Because chronic dermatitis produces cracks and blisters in the skin, any type of chronic dermatitis may lead to bacterial infection.

Contact dermatitis is skin inflammation caused by direct contact with a particular substance.  The rash is very itchy and is confined to a specific area.  Substances can cause skin inflammation by one of two ways — irritation (irritant contact dermatitis) or allergic reaction (allergic contact dermatitis).

Irritant contact dermatitis, which accounts for 80% of all cases of contact dermatitis, occurs when a chemical substance causes direct damage to the skin; symptoms are more painful than itchy.  Typical irritating substances are acids, alkalis (such as drain cleaners), solvents (such as acetone in nail polish remover), strong soaps, and even plants.  Some of these chemicals cause skin changes within a few minutes, whereas others require longer exposure.  As with most conditions sensitivity of the skin to irritants depends on each individual.  Even very mild soaps and detergents may irritate the skin of some people after frequent or prolonged contact.

Allergic contact dermatitis is a reaction by the body's immune system to a substance contacting the skin.  Sometimes a person can be sensitized by only one exposure, and other times sensitization occurs only after many exposures to a substance.

Symptoms and Diagnosis

Short-term symptoms of eczema include itchy skin, redness and tiny bumps or blisters.  If these symptoms remain untreated, the skin can become thick, scaly and dry, with areas of hair loss and colour changes.  Skin affected by long-term eczema is more vulnerable to further infections, usually caused by bacteria.

Prevention and Treatment

Contact dermatitis can be prevented by avoiding contact with the causative substance.  If contact does occur, the material should be washed off immediately with soap and water.  If circumstances risk ongoing exposure, gloves and protective clothing may be helpful.  Barrier creams are also available that can block certain substances from contacting the skin.