Contact Dermatitis
The term dermatitis means inflammation of the skin. There are two types of dermatitis, endogenous which means an inbuilt tendency to develop skin dermatitis, and exogenous, where dermatitis is produced through contact with substances on the skin, and is known as contact dermatitis. The most common site for occupational cases of contact dermatitis is the hands, but any exposed area of the body including arms, face, legs, feet, and neck can be involved.
Types of contact dermatitis
Irritant Contact Dermatitis- Acute irritant contact dermatitis is caused by strongly acidic or alkaline substances touching the skin producing a burning sensation for example where skin comes in contact with strong chemicals or wet cement.
- Chronic or cumulative type of irritant contact dermatitis often takes time to develop, and is the result of breakdown of the skin barrier, and is caused by substances which irritate and dry the skin.
Allergic Contact Dermatitis- This is caused by a substance in contact with the skin to which it develops an allergy to. It may be delayed for several hours or days before a reaction develops. However when you become allergic to a particular substance, even a very low concentration of the substance can produce a dermatitis. This occurs much less commonly than irritant contact dermatitis.
Contact Urticaria- This is where the skin develops an immediate allergic response to contact with a particular substance. This produces a localised hive reaction on contact with the substance. It is caused by a different mechanism to the other types of contact dermatitis. The most common is latex allergy.
Almost 3/4 of all occupational (work related) contact dermatitis is caused by irritant contact dermatitis, and 1/4 by allergic contact dermatitis. Cases of contact urticaria are rare except in the health industry.
Irritant contact dermatitis
Causes
The most common cause of irritant contact dermatitis is from constant contact with water. Other skin irritants include soaps, detergents, cleansers, shampoos, disinfectants, solvents, mineral oils, paper towels, dust, hard particles, heat , sweating and low humidity. People who have an atopic history, that is have a previous history of asthma, hayfever or eczema are several times more likely to develop irritant contact dermatitis. It is important to advise patients with this history to avoid or restrict from working in jobs where contact with irritants can occur. Also precautions should be taken in the work place to protect the skin from the beginning.
The damage to the skin by the irritants often take some time to occur, and it can take many months for the skin to recover completely. Once someone develops irritant contact dermatitis and the skin barrier is broken, certain chemicals which can produce an allergic reaction are more likely to penetrate the skin. So it is important to protect the skin before the skin barrier is broken by irritants.
Management and ongoing prevention of irritant contact dermatitis
It is important to alert and identify people with a background of eczema that they have an increased risk of irritant contact dermatitis. They can then take precautions to prevent irritants coming in contact with their skin right from the beginning of their job or career.
It is important where possible for all workers to minimize contact with irritants. This can occur through glove use, and different types of gloves are recommended for different duties. In addition, gloves should be removed or changed regularly to minimize sweating which is irritating to the skin. Protective clothing should be worn when exposure to irritants are likely in a particular job. If chemicals are spilled on to the skin or clothing, this must be thoroughly washed off, and a new set of clothing worn.
Skin care in the workplace should involve avoidance of some soaps and cleansers which are particularly harsh on the skin and substituting these with soap free washes or soap substitutes matched to the same pH as the skin. It is important to dry thoroughly after washing especially between fingers and under rings. Drying the hands with towels or air dryers is less irritating than using paper towels. After washing the hands it is important to moisturize the hands with a non perfumed moisturizer. Always rub the moisturizer into the hands well including the web spaces, and extend this to the fingers and wrists. Develop a routine for the worker, and this will aid in the recovery from the episode of irritant contact dermatitis. It is important to use an appropriately strong topical steroid to the irritant dermatitis till the problem clears completely. Once the dermatitis clears preventative measures must be taken to reduce the likelihood of the same problem recurring.
Allergic Contact Dermatitis
The development of allergic contact dermatitis varies considerably between individuals. Often it takes months or even years of contact with a particular substance, and then suddenly for reasons not well understood, a person becomes allergic to it. However once a person becomes allergic to something, a rash will develop whenever they touch or come into contact with that particular substance. The rash of allergic contact dermatitis is similar to irritant contact dermatitis, but it may occur more suddenly, and more severe sometimes even with blistering. A widespread dermatitis may develop in other areas of the body not in contact with the allergen, and this is a hypersensitivity reaction to the allergen.
The diagnosis of allergic contact dermatitis is made by patch testing, and there are many allergens that can be tested. A standard series which involves the most common allergens encountered is often used. It is important to inform the doctor who is doing the patch testing the various products and material safety sheets of the products used in the workplace.
Management and ongoing prevention of allergic contact
This is similar to that of irritant contact dermatitis. The person who is diagnosed with allergic contact dermatitis should be informed about the sources of the allergen that caused the reaction, and avoid all contact with those sources. If a person cannot work without developing the rash, then either job modification or a change of duties is recommended.
Dr. Ernest Tan
MBBS FACD
Consultant Dermatologist
Burswood Dermatology
87 Burswood Road
Victoria Park WA 6100
Australia
Tel: 618 9470 3064
Fax: 618 9470 4479Labels: Dermatitis
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