What is contact dermatitis?
The words ‘dermatitis’ and ‘eczema’ are interchangeable and mean the same thing. Contact dermatitis, therefore, is the same thing as contact eczema. For simplicity we will stick to the word ‘dermatitis’ in this leaflet.
Dermatitis means an inflammation of the skin. The term ‘contact dermatitis’ is used when this inflammation is caused by contact with something in the environment.
What causes contact dermatitis?
Two main groups of things in the environment cause contact dermatitis: irritants and allergens.
Irritants are substances like detergents and solvents that strip the skin of its natural oils, and cause dermatitis to develop if contacted frequently and without skin protection. When this happens, the skin changes are known as an irritant contact dermatitis. The most important factor in causing this type of contact dermatitis is the amount of irritants to which you are exposed. It is particularly common in people who do a lot of wet work, for example nurses, hairdressers, those who work in bars, and those in the catering trade.
Allergens are things to which your immune system can develop a specific reaction after you have come into contact with them. Examples include substances such as nickel, rubber, and perfumes or preservatives used in some creams and cosmetics. This type of dermatitis is called an allergic contact dermatitis. It is not known why some people who are exposed to these allergens develop it while others do not.
Sometimes substances such as proteins in fruit and vegetables can cause an immediate allergic reaction leading to itchy skin swellings known as contact urticaria (hives), which in turn can aggravate your dermatitis.
Contact dermatitis cannot be caught from nor spread to other people.
Is contact dermatitis hereditary?
People with a tendency to asthma, eczema and hay fever develop irritant contact dermatitis more easily than others, and this tendency does run in families.
What are the symptoms of contact dermatitis?
Itching of the skin is the commonest symptom, and this can be intense. Sometimes the skin becomes sore, and painful cracks can develop over the backs of the fingers when dermatitis affects the hands.
What does contact dermatitis look like?
The commonest areas on which contact dermatitis occurs are the hands, arms, face and legs. During a flare, contact dermatitis inflames the skin surface making it look red and scaly. Sometimes, tiny water blisters develop and these leak fluid when scratched. When the contact dermatitis is less active, the skin looks thick and dry, and painful little cracks can form over joints.
How will it be diagnosed?
Irritant contact dermatitis is diagnosed simply by knowing which irritant substances your skin is exposed to, and how often this occurs.
Allergic contact dermatitis is diagnosed by a procedure available in specialist dermatology departments known as patch testing. This involves putting sticky patches containing different substances on your back. The patches are taken off 2 days later, and the doctor or patch test nurse will then look at your back to see which ones have reacted. They will need to look again after a further 48 hours to see if there are further reactions.
Can contact dermatitis be cured?
Yes - if you can greatly reduce your contact with irritants, then your irritant contact dermatitis will improve or clear.
If patch testing shows that you are allergic to a specific allergen, then avoiding that allergen will usually lead to a big improvement or even complete clearance of your allergic contact dermatitis.
To find out about available treatments please visit this page on the website of the British Association of Dermatologists