About contact dermatitis

Contact dermatitis, or contact eczema (‘dermatitis’ and ‘eczema’ can be used interchangeably) is the name given to types of eczema that occur as a result of contact with irritants or allergens in the environment. Contact dermatitis affects 9% of the UK population and is the most common type of work-related skin disease.

What is contact dermatitis?

Contact dermatitis can be broadly divided into two types: irritant contact dermatitis (ICD), where eczema develops as a result of contact with substances that directly damage or irritate the skin; and allergic contact dermatitis (ACD), which develops when an individual becomes sensitised or allergic to something in the environment. However, there is overlap between the two and it is possible to have both at the same time.

What is irritant contact dermatitis?

Irritant contact dermatitis is a reaction to frequent contact with everyday things that irritate the skin, such as soap, detergents, oils, hair cosmetics, bleach, household cleaning products, cold wind, and raw food. 

Common sites for irritant contact dermatitis are the hands and face, but the condition can affect other parts of the body. A person who had atopic eczema as a child is at an increased risk of developing irritant contact dermatitis.

Symptoms of irritant contact dermatitis range from mild dryness and skin redness to the appearance of skin burns. It can be painful, red, fluid-filled and ulcerated.

Occupations at greatest risk for developing irritant contact dermatitis include: chefs, hairdressers, metal workers, nurses, cleaners and construction workers.

What is allergic contact dermatitis?

Allergic contact dermatitis is much less common than irritant contact dermatitis. It is caused by an individual developing a specific allergy to a chemical. For an allergy to develop, repeated exposure to the chemical is required over a period of time, usually months or years.

Once this has happened, the body’s defence mechanisms learn to recognise the chemical and the individual develops a reaction when the chemical contacts the skin again. The allergy is ‘remembered’ by the body for many years. In medical terms the body has become ‘sensitised’ to a chemical.

The reaction can be immediate or delayed depending on the type of allergen in question. Most frequently seen on the hands, allergic contact dermatitis can cause the skin to become dry, red, split, cracked, weeping, fluid-filled and intensely itchy, sore, painful and stinging. The severity will depend upon the allergen and the length of time it is in contact with the skin.

The most common contact dermatitis allergens in Europe are: fragrance, thiomersal (antiseptic), cobalt (cement), nickel, paraphenylenediamine (hair dye, henna, temporary tattoos) and formaldehyde (chemical preservative).

If allergic contact dermatitis is thought to be a possibility, then you need to be referred to a dermatologist, who may recommend patch testing.

For more information on contact dermatitis, treatments and patch testing, please see our Contact Dermatitis booklet