Contact Dermatitis

Contact dermatitis is a skin rash caused by a substance which reacts in contact. You may patch tests to identify the offending substance. A steroid cream or ointment will clear the rash. However, long-term treatment is to avoid contact with the offending substance.

On this page

  • What is dermatitis?
  • Contact dermatitis Types
  • What are the symptoms of contact dermatitis?
  • Can you have different types of dermatitis at the same time?
  • Do I need any tests?
  • What is the initial treatment for contact dermatitis?
  • What is the long-term treatment of contact dermatitis?
  • More help and information
  • References

Dermatitis is inflammation of the skin. The dermatitis is also called eczema. It makes the skin red, itchy, which also may blister. There are various types of dermatitis. However, dermatitis are generally grouped into two main types:

  • Dermatitis caused by a problem from inside the body. For example, atopic eczema (atopic dermatitis) is a common condition that tends to run in families. If you have atopic eczema born with a tendency for the skin to become inflamed. Several parts of the skin tend to flow with inflammation occasionally. See separate leaflet called 'atopic eczema' for details.
  • Dermatitis caused by a substance from outside the body. Normally, this causes patches of inflammation in the skin areas that were in contact with the substance. This is known as contact dermatitis. If you avoid the harmful substance, inflammation of the skin should disappear.

The rest of this leaflet is only about contact dermatitis.

There are two types of contact dermatitis – irritant and allergic.

Irritant contact dermatitis

This is caused by direct contact with a substance that irritates the skin. This is common and causes about 8 out of 10 cases of contact dermatitis. It most commonly affects the hands. Are irritants that can cause inflammation in most people if they are in contact long enough, often enough and strong enough concentration. For example:

  • Detergents (detergent, soap, bleach, etc..) People who do a lot of cleaning are prone to irritant contact dermatitis.
  • Solvents (such as gasoline), oils and other chemicals used in different workplaces.
  • Acids and alkalis, including cement.
  • Dust, dust and dirt.
  • Certain plants (eg buttercups, anemones, clematis, hellebore, mustards).

You can develop irritant contact dermatitis quickly from a single exposure to a strong irritant. For example, contact with a strong chemical in a work situation. However, it also can develop irritant contact dermatitis due to repeated exposure to weak irritants. For example, a detergent used to wash dishes regularly.

There is often a vicious circle. A patch of skin may become sore after being in contact with an irritating substance. This causes some skin damage. Once damaged, the skin is more easily affected by irritants. Thus, the additional contact with even small amounts of the substance, may cause further damage and inflammation and so on.

Allergic Contact Dermatitis

This occurs when the immune system reacts against a specific substance. The substance is then called an allergen. It only takes a small amount of allergen skin contact that causes the rash.

You are not born with this allergy – you must have first contact with the allergen that has sensitized immune system. Once sensitized, reactive skin and inflamed the additional contact with the allergen. That's why you may suddenly develop a skin allergy to something that has been in contact with many times before. It is unclear why some people become allergic to some substances and most people do not.

Many substances can cause allergic contact dermatitis. The most common are:

  • Nickel – this is the most common cause. The nickel is produced in many types of metal. For example: jewelry, studs in jeans and other apparel, bra straps, etc. Therefore, it is common to develop itchy red spots on the skin with those things.
  • Cobalt – traces of this metal can be found in some jewelry.
  • Cosmetics – including perfumes, hair dyes and nail varnish resins preservatives.
  • Skin Supplements and rubber (shoes, clothes, etc).
  • Preservatives in creams and ointments.
  • Plants – The most common culprits are chrysanthemums, sunflowers, tulips and daffodils, primula.

Sometimes the cause is not clear, you may need tests to determine the cause (see below).

Irritant contact dermatitis

The main symptoms are redness, burning, itching and pain in the affected areas of the skin. The onset of skin reaction is usually within 48 hours of contact with the irritant. Strong irritants can cause immediate reactions, while mild irritants require longer or repeated exposure to cause a reaction. Symptoms only occur in areas of skin exposed to the irritant.

Allergic Contact Dermatitis

The main symptoms are redness, itching and scaling of the affected areas of the skin. There is often a delay of several hours to several days before they develop symptoms following contact with the allergen (or chemically sensitize the object). The site of the symptoms of skin rash and is mainly where contact had been. For example, eyelids and cheeks if allergy is a cosmetic. However, as it is a true allergy, other skin areas that were not in direct contact with the allergen may develop a rash.

Yes For example, you can be born with atopic eczema. Their work may involve the frequent use of a solvent which can cause irritant contact dermatitis. In addition, you can also develop an allergy to nickel and so find that you get patches of inflammation over jean posts, or if you wear jewelry, etc.

The cure for most cases of contact dermatitis is to avoid the harmful substance. In many cases tests are not necessary, as it is often clear that the substance has caused the eruption. However, sometimes it is not clear what the cause of the eruption. Or it may be a substance which is an additive for various things and can not determine what is. This is where patch testing may be advised.

Patch tests

Patch tests help find the cause of allergic contact dermatitis. You need to be referred to a dermatologist (skin specialist) for patch testing. Place a small amount of various substances that can be the cause of the rash. This is usually done in the skin of the back, in groups of 10. The skin is covered with an adhesive bandage.

After two days the dressing is removed and the skin is examined to see if there is a reaction to any of the substances tested. The skin is also commonly examined again after two days in case you have a delayed reaction to some medication. Sometimes the skin can be examined again one week after the initial substances is placed on the skin.

If no skin reaction in the patch tests, this may also be useful to rule out allergic contact dermatitis as a cause of your skin problem.

As mentioned, the main treatment is to avoid the harmful substance. However, your skin may also have pain, itching and flaking as different initial treatments may be suggested to help cure the symptoms.

Hydrating emollients ()

If inflammation of the skin is not too bad, then simply use an emollient (moisturizer) can often be all you need until the inflammation settles and clears the rash. Soap substitutes may also be suggested.

Topical steroids

Topical steroids are creams, ointments and lotions that contain steroids. They work by reducing inflammation in the skin. They come in different brands and strengths. As a general rule, you should use the softer works. You can buy a soft cream steroid (hydrocortisone) without prescription in pharmacies. If a being soft does not work, a stronger one can be prescribed by your doctor.

Topical steroids are usually applied once or twice a day twice in a thin layer to the affected area until inflammation disappeared. This may take up to two weeks or more. Once the swelling is gone, stop the topical steroid. You must wait for several minutes after using an emollient (moisturizer) before applying a steroid cream.

Short courses of topical steroids (less than four weeks) are usually safe and rarely cause problems. Side effects can develop if topical steroids are used for long periods, or short courses are repeated often. The main concern is whether strong steroids used on a long term basis. Most people with contact dermatitis only need a short course. See separate leaflet called "Topical Steroids for Eczema 'for more details.

Other treatments

An antibiotic may be prescribed if the inflammation becomes infected. This is not common in the majority of episodes of contact dermatitis. In rare cases, treatment with steroid tablets is necessary if you have a large area and severe skin inflammation.

Rarely, treatment with steroids is not clear contact dermatitis and other treatments can be suggested. These may include tacrolimus cream and treatment with drugs such as azathioprine, cyclosporine, and oral retinoids. Ultraviolet (UV) light exposure, sometimes it helps to take a drug called psoralen, sometimes also recommended. This is known as psoralen combined with ultraviolet A (UVA) (PUVA). Grenz rays (low energy electromagnetic rays) are usually used when other treatments fail.

Once the inflammation has settled, the main objective is to prevent it from happening again.

Avoiding cause

If the offending substance can be identified, so if you can prevent the dermatitis will usually clear and not return. (There are some exceptions, for example: irritant contact dermatitis caused by chromium in cement can sometimes lead to a rash long term – even if contact with chromium stops.).

Avoid an irritant or allergen can be easier said than done. For example:

  • Some substances that cause allergic contact dermatitis are additive to everyday things like clothes and leather shoes, rubber, metals, cosmetics, etc. They can be difficult to avoid completely. However, your doctor or skin specialist can give you advice on whether the substance is likely to occur and how to avoid it.
  • For some people, their work involves the use of substances that can cause irritant contact dermatitis. Unless you change your job, you may not be able to completely avoid the substance. Attention good hand (described below) can help.

Hands

Approximately 3 out of 4 cases of contact dermatitis occur on the hands. Many cases are due to irritants (instead of allergies) of chemicals and other substances used in the workplace. To help prevent irritant contact dermatitis of the hands, get into a routine of good hand care:

  • Do not keep your hands in water for long.
  • Wear protective gloves whenever possible when working with chemicals, detergents, etc.
  • Consider using a sunscreen to help protect skin from his hands during work.
  • Use a mild skin cleanser instead of soap for washing hands.
  • Dry your hands thoroughly after washing.
  • Use plenty of moisturizer and apply frequently. This helps to keep the skin on your hand and flexible to prevent cracking.

Intermittent use of topical steroids

Topical steroids provide a worsening of symptoms, but are not a long-term cure of contact dermatitis. The only long-term cure is to identify the cause and to prevent it.

However, it may be useful to have a topical steroid in your home medicine box. You can develop an exacerbation of symptoms if accidentally come into contact with a substance to which you are allergic. For example, if you use a new cosmetic or some jewelry that did not realize their allergen content. A short course of topical steroids, is welcome to relieve the rash and inflammation.

National Eczema Society

Hill House, Highgate Hill, London, N19 5NA
Tel (Helpline): 0800 089 1122 Web: www.eczema.org