What is Contact Dermatitis?
“Dermatitis” means inflammation of the skin. “Contact” dermatitis is a particular type of skin inflammation caused by contact with certain substances found in the environment.
The inflammation appears as redness, swelling, itching and, and at times, blistering. In severe cases, the condition may cause considerable discomfort, and, on occasion, can even interfere with a person’s ability to work. Contact dermatitis is treated by our doctor for patients in our region.
What substances cause Contact Dermatitis?
The most common cause of Contact Dermatitis in the United States is the poison ivy plant (and its relatives, poison oak and poison sumac).
Another very common cause is nickel, a substance widely used in costume jewelry, in metal clasps on women’s clothing, and in watch bands. Other causative substances include detergents, cleaning compounds, cosmetics, etc.
Contact Dermatitis is extremely common. At work, at home, in the garden and elsewhere we are exposed to innumerable chemicals, metals, plants, etc. Thus, there is always the possibility that some of them may cause a reaction in susceptible individuals.
How does Contact Dermatitis develop?
There are two ways. The first is by means of irritation – chemical or mechanical. An example of a chemical irritant dermatitis is one caused by the detergents or cleaning compounds mentioned previously. An example of mechanical irritant dermatitis is one caused by prickly fiberglass particles, or the scratchiness of wool clothing next to the body.
If the irritant is strong – for instance, an accidental spill of lye on your hands – a single exposure will cause a violent inflammatory reaction. The skin will become itchy, red, swollen, and often develop tiny water blisters, called “vesicles,” or even large blisters.
If the irritant is weak, the initial skin reaction will be mild. Only after repeated exposures such as repeated exposures to soaps and detergents – will the accumulated damage to the skin be easily seen. When the dermatitis develops slowly in this manner, the skin shows dull red, itchy, thickened patches, at times accompanied by blistering. If the inflammation is located on areas where the skin bends, such as the fingers, painful cracks may develop.
The second way Contact Dermatitis is developed is by sensitization. This means that the first contact with the substance causes no immediate trouble, but the exposure “sensitizes” or changes the sensitivity of the skin. Afterward, whenever the skin is exposed to the same substance – even slightly – it becomes inflamed. This is called an “allergic reaction,” and a perfect example of it is poison ivy dermatitis.
Another uncommon but interesting mechanism in the development of Contact Dermatitis is what is called “photo-allergy.” This means that some of the chemicals contained in perfumes, soaps or medications may “sensitize” the skin to sun rays. Afterward, when the person is exposed to sunlight, a rash develops.
The type of skin reaction caused by sensitization is the same as those caused by irritants.
Who gets Contact Dermatitis?
Actually, anybody can. But naturally the greater the activity and exposure of the individual, the greater his or her risk of developing it. Housewives are frequently affected because their daily work requires them to handle soaps, detergents, cleaning fluids, sprays and other kinds of irritating substances. The condition is common in industrial workers – auto mechanics, beauticians, bricklayers – for the same reason, and is usually called “industrial dermatitis.”
Are some parts of the body more affected by Contact Dermatitis than others?
Yes. The hands are most prone to develop contact dermatitis, since they are routinely exposed to so many different types of irritants. However, the face, feet and rest of the body are susceptible too. The face is often affected by cosmetic products including soaps, shampoos, creams, lipsticks, hair sprays, shaving creams and after shave lotions. The feet may be affected by materials used in the manufacture of shoes. Rashes on the body are usually caused by articles of clothing, bedding or the chemicals used to wash them.
Sometimes air-borne substances – tiny particles flying through the air – may cause severe rashes involving the face and exposed parts. For example, dermatitis may develop on people sensitive to poison ivy when they are exposed to the smoke of burning poison ivy leaves.
How will the doctor identify the cause of my Contact Dermatitis?
In some cases the location of the rash may suggest the cause. For instance, a rash around the wrist is easily identified as caused by a watchband. One across the forehead may be the result of a hat band. Rashes in the armpits are often due to deodorants.
But in the majority of cases, identification of the cause is not that simple. In order to help determine the cause of your dermatitis, our physician will ask you many questions about what you do, what you’ve handled at home and in your work, if you use gloves to protect your hands at work or when washing the dishes, what hobbies you have, etc.
You should try to help by remembering all your activities – gardening, painting, using metal polishes, touching plants, etc. – which may have caused irritation of your skin. You should mention if you’ve recently changed employment, or recently been on vacation away from your usual environment. In many instances, your doctor has to act like a detective to search for a clue to the diagnosis.
Confirmation, and sometimes even detection, of the specific substance that caused the rash may often require further study and patch tests.
What are patch tests?
A patch test is the application to the skin of a small amount of the material suspected of causing the rash. The “patch” is usually placed on the healthy skin of the forearms or back, covered with a small bandage or band-aid, and left on the skin for 24 – 48 hours. (If you feel intense itching or burning from the patch, it should be removed immediately).
A positive patch test shows redness, swelling or even blistering of the small area where the substance was in contact with the skin. It is actually a miniature reproduction of the rash and thus pinpoints the trouble-making substance.
Your doctor will decide whether you need a patch test, and what substance should be tested, after careful consideration of your medical history and study of the location and appearance of your rash. Never try a patch test yourself, it may cause serious harm.
How will my Contact Dermatitis be treated?
If the cause of your rash is identified, you will, of course, be instructed to avoid further contact with it. If the specific cause cannot be found, all possible causes should be eliminated.
We will select the appropriate treatment, depending on the degree of inflammation of the skin. Local treatment (medication that you apply to the skin) may range from wet dressings, to lotions, to preparations containing cortisone-derivatives. If we feel that increased hydration of the skin may be beneficial, we may also prescribe a topical moisturizer or medication with a moisturizing base.
In selected cases, we may also prescribe or administer by injection medications such as antihistamines or cortisone derivatives. These are aimed at reducing the itching and inflammation.
What can I expect from treatment for Contact Dermatitis?
If the cause of the rash is identified, and you avoid further contact with it, appropriate treatment will stop the itching and eventually cause the rash to disappear. In the case of “one time” exposure to strong irritants or sensitizers (like poison ivy), the rash will probably persist for about a week and then gradually subside. It will heal with peeling, and is not likely to leave any sort of scar.
Those rashes resulting from repeated contact – usually of a dry, thickened appearance – tend to be more persistent. The rash heals more slowly, often leaving a patch of darker skin. This, however, will eventually fade.
What can I do to help control my Contact Dermititis?
- First, do not scratch the rash. Scratching can lead to bacterial infection causing pus-filled pimples, scabs or boils. (If this does occur, immediately inform us, we will probably prescribe an antibiotic which will rapidly control the infection).
- Second, follow our instructions. Avoid contact with the causative substance or a chemically related one. Use the prescribed medication or medications. Also follow instructions regarding hygiene and protection of the affected area.
- Third, try to avoid contact with other chemicals that may be irritants. Inflamed skin is more susceptible to irritation by other agents. And once you have had Contact Dermatitis, it may be wise to be extra careful with new substances. If contact with possibly troublesome substances is unavoidable, protect your hands with vinyl or plastic gloves, or with whatever other protective method we may recommend.