Contact Dermatitis

What is contact dermatitis?

Dermatitis means an inflammation of the skin. Contact dermatitis is a term used when this inflammation is caused by contact with something in the environment. The changes of dermatitis seen in the skin take the form of eczema; hence it may sometimes be referred to as contact eczema but may have nothing to do with atopic tendencies and atopic eczema.

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 (especially in hand dermatitis), e.g. 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, when touched, 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 on the fingers when dermatitis affects the hands. Other areas that can be affected, and become red and raised, include the arms, face, legs and feet.

What does contact dermatitis look like?

The commonest areas on which contact dermatitis occurs are the hands, neck, 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 patch testing. This involves putting sticky patches containing different substances on your back. The patches are taken off 2 days later, and the doctor will then look at your back to see which ones have reacted. They will need to look again after a further 24 to 48 hours to see if there are further reactions.

Can contact dermatitis be cured?

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.

How can contact dermatitis be treated?

The main way of treating contact dermatitis is to identify its cause (irritant or allergen) and then to remove it or reduce contact with it. Complete avoidance may be easy for some types of allergic contact dermatitis, for example to a substance such as rubber. However complete avoidance is impossible for some people whose irritant contact dermatitis is due to prolonged contact with water and soap. In cases such as these measures to protect the skin, such as wearing gloves and using emollient creams, may help. If the problem is severe enough, some people may have to change their job, if they cannot otherwise avoid coming into contact with irritants.

It may take several months for contact dermatitis to settle, so topical steroid creams and moisturisers are used to help the skin heal and to reduce the itching and redness. Topical steroid creams come in different strengths and it is important that you use the right strength for the right length of time; your doctor will advise you on this. It is also very important to protect your skin and to keep it supple by using a suitable emollient several times a day. Thick emollients are best for the hands, and it is important that you find one that you like to use.
People with very severe contact dermatitis may need other treatments such as steroid tablets, or medicines such as ciclosporin or azathioprine, to settle things down.

What can I do?

  • If you think you might have contact dermatitis, you should see your doctor who may then refer you to a dermatologist for further assessment and patch tests.
  • If you have contact dermatitis, you can look after your skin by avoiding the allergic reaction causing substances (though this is easier said than done).
  • Use moisturisers several times a day.
  • Take time to look after your skin and follow your doctor’s advice on using the various creams and treatments. If they are not working, go back and see your doctor.

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