- What is Contact Dermatitis?
- Statistics on Contact Dermatitis
- Risk Factors for Contact Dermatitis
- Progression of Contact Dermatitis
- Symptoms of Contact Dermatitis
- Clinical Examination of Contact Dermatitis
- How is Contact Dermatitis Diagnosed?
- Prognosis of Contact Dermatitis
- How is Contact Dermatitis Treated?
- Contact Dermatitis References
- Drugs/Products Associated with Contact Dermatitis
What is Contact Dermatitis?
Dermatitis means inflammation of the skin caused by something touching the skin. Contact dermatitis is a condition referring inflammation caused by direct contact with an irritating or allergy provoking substance. The two main types of contact dermatitis include:
- Irritant contact dermatitis
- Allergic contact dermatitis
Statistics on Contact Dermatitis
The most common type of dermatitis is irritant contact dermatitis, which accounts for about 80% of all cases of contact dermatitis. In Australia, occupational irritant contact dermatitis contributes to time taken off work - the incidence of confirmed cases of irritant contact dermatitis is 20.5 per 100,000 workers. This means that out of 100,000 workers, about 20-21 people suffer from occupational contact dermatitis, which may necessitate taking time off work and change of occupation.
Risk Factors for Contact Dermatitis
If you have had or suffer from allergic conditions such as eczema, hay fever or asthma, or there is a strong family history of these conditons, you may have more sensitive skin and be more likely to develop contact dermatitis. Factors that may aggravate irritant dermatitis include:
- Water, especially frequent hand washing and prolonged contact with water.
- All types of soaps, detergents, shampoos and other cleaning agents.
- Solvents such as turpentine, kerosene, fuel, thinners
- Oils and cooling fluids
- Hot temperatures and sweating
- Dusts in the environment
- Common metals such as nickel and cobalt. Allergy is common in women who wear jewellery, from the backing of watches and jean studs and buckles.
- Chemicals used in the manufacture and preservative of rubber products, such as thiurams, mercaptobenzothiazoles and carbamates.
- Hairdressing allergens such as hair dyes (paraphenylene diamine or PPD) bleach (ammonium persulfate and hydrogen peroxide).
- Chromate, which is present in cement and leather.
- Substances applied to the skin such as preservatives in products such as creams, gels, lotions, shampoos; antiseptics in hand creams; fragrances (often in toiletries) deodorants.
Progression of Contact Dermatitis
Most cases of irritant contact dermatitis develop over time, with frequent and repeated exposure to skin irritants such as water, soaps and detergents. Allergic contact dermatitis is caused by an allergy to something which comes in contact with the skin and causes a delayed reaction. It is called a delayed reaction because the rash may not appear for some time after contact with the allergic substance, ranging from hours to days. The rash seen in allergic contact dermatitis is often similar to the rash of irritant contact dermatitis. Most contact dermatitis resolves spontaneously in about four to six weeks if further exposure is prevented. However, we have to identify the agents that are causing the dermatitis to be able to achieve long term control of disease.
Symptoms of Contact Dermatitis
When you visit the doctor, he or she may ask the following questions, as necessary, to try and identify the most likely diagnosis and cause for your symptoms.
- Is there a personal or family history of any allergic diseases (eczema, hay fever, asthma)?
- What is your occupation?
- Have you had repeated exposure to any allergens / irritants or do you notice any initiating or aggravating factors relating to episodes of contact dermatitis? (In acute allergic contact dermatitis, the lesions usually appear within 24-96 hours of exposure to the allergen).
- Where is the contact dermatitis predominantly located? (Parts of the body which come in contact with particular substances may help identify the cause).
- Are there any associated symptoms such as itch, redness, warmth, tenderness or signs of infection (pus, skin redness, fever)?
- Is there a history of previous contact dermatitis or a similar presentation?
- Have there been any new medications / cosmetic or chemical applications that have been applied to the skin?
Clinical Examination of Contact Dermatitis
Most cases of contact dermatitis appear in a similar fashion, regardless of the mechanism or cause of inflammation. The different responses can be categorized into acute, subacute, and chronic phases, depending on the time course taken for the disease to develop.When your doctor examines you, he or she may look for the following features.
- Acute contact dermatitis usually appears as a rash with small, clear, fluid filled pockets that develop on red and swollen skin. As the lesions break down, the skin can begin to weep fluid.
- Subacute contact dermatitis is characterized by less swelling and formation of papules.
- Chronic contact dermatitis presents with minimal swelling. Features such as scaling, fissuring / cracking of the skin and thickening of the surface layers of the skin may be present.
How is Contact Dermatitis Diagnosed?
The doctor will usually be able to make a diagnosis of contact dermatitis based on what is present clinically and no specific tests are necessary. The rash will usually clear up if contact with the allergic / irritating substance is avoided. In some cases of contact dermatitis, you may visit a skin specialist called a dermatologist, to have patch testing performed.Patch testing is the special technique used to diagnose causes of allergic dermatitis. Small amounts of diluted chemicals are placed on discs, about the size of a 5c coin. The discs are placed on a strip of tape called a patch, there are about 10 discs per patch. Several patches are then stuck onto your back and left there for 48 hours. The doctor will give you specific instructions such as keeping your back dry and not scratching the tape. After 48 hours, the tapes are removed and your back is observed for any allergic reactions. You usually return for a further reading after another 2-3 days.
Prognosis of Contact Dermatitis
Most cases of contact dermatitis are easily treated and will resolve with time if we avoid the substance that is causing the allergic or irritant reaction. In a few cases where the cause is unidentified, the outlook in the long term is not as favourable. Occasionally, contact with an allergy provoking substance can precipitate a reaction involving the immune system which results in a type of shock called anaphylactic shock.
How is Contact Dermatitis Treated?
The most important step in successfully managing contact dermatitis is to recognise how you are in contact with the allergic substance, so that you can avoid it. General measures to help relieve some of the symptoms and discomfort associated with contact dermatitis include:
- Emollient creams or ointments help soften the skin and moisturisers add moisture. These products are used to improve dryness and scaling of the skin and irritant contact dermatitis.
- Topical steroids are very effective and safe medications when used correctly. These work by reducing inflammation of the skin. Topical steroids should be applied once or twice daily to the areas of skin affected by disease.
- Topical or oral antibiotics may be used to treat secondary infection.
- Short courses of oral steroids may be used for severe cases of dermatitis. Corticosteroids have anti-inflammatory effects and modify the body's immune response to various stimuli.
Contact Dermatitis References
- Buxton P. ABC of Dermatology. London: BMJ Publishing Group Pty Ltd; 2005
- Calvin O, Lawley J. Eczema and Dermatitis. Harrisons Principles of Internal Medicine. New York: The McGraw-Hill Companies; 2006
- Friedmann P. ABC of allergies: Allergy and the skin II - Contact and atopic eczemaBMJ, 1998; 316:1226
- Kumar V, Abbas A K & Fausto N. Robbins & Cotran Pathologic Basis of Disease. China: Elseiver Saunders; 2005
- Michael J. Contact Dermatitis. E-medicine [serial online]. 2006 [cited 9th September 2006]. Available from URL: http://www.emedicine.com/emerg/topic131.htm
- Nixon R L, Frowen K E. Contact dermatitis and occupational skin disease. Med J Aust. 2005
- Rotstein H. Principles and Practice of Dermatology. Australia: Reed International Books Australia Pty Ltd; 1998
- Saary, J, Qureshi, R, Palda, V, et al. A systematic review of contact dermatitis treatment and prevention. J Am Acad Dermatol 2005; 53:845
- White G. Colour Atlas of Dermatology. Spain: Elsevier Limited; 2004.
Drugs/Products Used in the Treatment of This Disease:
- Azahexal (Azathioprine)
- Cysporin (Cyclosporin)
- Panafcortelone (Prednisolone)
- Phenergan (Promethazine hydrochloride)
Modified: 6/2/2008 Created: 8/9/2006
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