Contact eczema, or contact dermatitis as it is more commonly referred to, is the name given to those 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 (also known as occupational skin disease). There are two types of contact dermatitis:
Irritant Contact Dermatitis
Irritant contact dermatitis is a reaction to frequent contact with everyday things which irritate the skin, such as soap, detergents, hair cosmetics, bleach, 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 may range from mild dryness and skin redness to the appearance of skin burns (see the right-hand image). It can be painful, red, fluid-filled and ulcerated.
Weak irritants, for example, diluted acids, diluted alkalis, solvents, soaps, detergents, metallic salts, cement, resins and cutting fluids are the commonest cause of irritant contact dermatitis.
Occupations at greatest risk of developing irritant contact dermatitis include: chefs, hairdressers, metal workers, nurses, cleaners and construction workers.
Irritant Hand Eczema (sometimes called hand dermatitis)
There can be a variety of reasons why eczema occurs on the hands. Adults with a history of atopic eczema may find that in later life the condition reappears on their hands as a result of contact with irritants such as detergents, cleaning agents or white spirit.
This type of reaction is known as irritant contact eczema and can occur in anyone who regularly uses substances of this kind in their everyday life, as well as those who have a history of atopic eczema.
Allergic Contact Dermatitis
Allergic contact dermatitis is much less common than irritant contact dermatitis. Minute quantities of apparently harmless substances may cause severe allergic contact dermatitis.
Allergic dermatitis is caused by an individual developing a specific allergy to a chemical. For 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.
Allergic Hand Eczema (sometimes called Allergic Hand Dermatitis)
Allergic hand dermatitis may occur either on its own or against a background of atopic eczema. The hands are often scaly, dry and itchy and can be accompanied by blistering, soreness or splits in the skin. Common ‘sensitisers’ include:
- Nickel – found in many jewellery items, studs of jeans, zips and watch straps
- perfumes found in cosmetics and toiletries
- preservatives found in cosmetics, toiletries, topical medicines such as creams, steroids, eye and ear drops.
Many industrial chemicals also need preservatives:
- phenylene diamine – found in hair dyes is a well known sensitiser
- plants such as primula obconica and chrysanthemums.
If allergic hand eczema is thought to be a possibility then you are likely to be referred to a dermatologist for possible patch testing.
Nickel sensitivity is common in the UK, especially in women. Anyone can become allergic to nickel, but more cases begin during the teenage years when girls start to wear cheap metal jewellery. Ear piercing can often start up a nickel allergy.
It is possible, but much less common, to become allergic to nickel later on in life. People who have been in contact with nickel for many years can suddenly become allergic to it for no reason.
We don’t know why some people become allergic to nickel when others don’t. But those with certain jobs are more likely to become sensitive to nickel: these include hairdressing, nursing, catering, cash handling and those handling metals.
Many people notice a red itchy rash under a piece of jewellery, jeans stud or watch strap which can be due to irritation and sweat.
The rash can start in one place or in a number of places on the body at the same time. If the condition carries on for a long time the skin will dry out and become red, scaly and cracked.
Normally the rash will appear wherever the nickel is in close contact with the skin, but it is possible for the rash to spread so that later on even areas that haven’t come into contact with the metal become red and itchy.
Once an allergic rash due to nickel has developed on a particular part of the body, it is possible for the rash to spring up again on that site whenever the body comes into contact with nickel, even at a different place on the body.
What to do next? Find out about treatment
You can find out about the range of treatments options for different types of eczema in our comprehensive Treatment area of the website.
Contact dermatitis affects 9% of the UK population and is the most common type of work related skin disease (also known as occupational skin disease).