Skin Allergy / Dermatitis Diagnosis & Treatment
Mrs. Smith’s lips began to itch and blister. After testing, her dermatologist said she was allergic to nickel. The problem? Holding nickel-plated hairpins in her mouth when setting her hair. When she stopped, so did the itching. Tom Black’s big toe was red and sore. His dermatologist diagnosed an allergy to rubber. The lining in one of Tom’s shoes had worn away, so his toe rubbed against a rubber lining. When he stopped wearing the shoes, his toe got better.
These are examples of allergic contact dermatitis. This condition can be caused by almost anything that comes into contact with the skin. A substance that causes allergic contact dermatitis is called an “allergen”. Most people do not react to an allergen. Some people will become allergic to a substance with time. Further exposure will produce an itchy rash.
Allergic contact dermatitis is not usually caused by things like acid, alkali, solvent, strong soap or detergent. These harsh chemicals, which can produce a reaction on anyone’s skin, are known as “irritants”. Although some chemicals are both irritants and allergens, allergic contact dermatitis results from brief contact with substances that don’t usually cause a reaction in most people.
What Dermatitis Looks Like
The skin gets red, swells, and blisters appear. Blisters may form and break, leaving crusts and scales. Later the skin may darken and become leathery and cracked. Allergic contact dermatitis can be difficult to tell from other rashes.
Discovering the Cause
The dermatologist and patient will discuss the materials that touch the person’s skin at work and home, to identify the allergen. The dermatologist may also perform patch tests. Patch tests are a safe and easy way to diagnose contact allergies. Small amounts of the possible allergens are applied to the skin for a fixed time, usually two days. Common allergens include nickel, rubber, dyes, preservatives, fragrances, and poison ivy, poison oak, and related plants.
Nickel Dermatitis
Nickel, part of certain metals, is found in many products. Many chrome-plated objects contain enough nickel to produce a reaction in sensitive people.
Stainless steel also contains nickel, but it is bound so tightly that it is safe for most nickel-sensitive individuals. Earrings containing nickel can cause earlobe dermatitis, a very common problem in people allergic to nickel. This may start with the needles used to pierce ears, and earrings. Only sterile stainless needles should be used for piercing. After piercing, wear only nickel-free earrings for at least the first three weeks.
Clothing fasteners made of nickel-buckles, zippers, buttons, and metal clips-can cause dermatitis. Nickel-sensitive people can substitute nylon accessories.
Sweating increases dermatitis in nickel-sensitive people. In the summer, items containing nickel can cause an itchy, prickly sensation within 15 to 20 minutes of touching sweaty skin. A rash may appear within a day or two. These same items can be worn for several hours without problems, if sweat is not present.
We do have a kit available through DermaSpa that can test products for nickel.
Rubber – A Frequent Offender
Rubber products often cause allergic contact dermatitis. Chemicals in rubber cause the reaction. Rubber-sensitive people must use something else. Rubber can also cause immediate allergic reactions, including itching or burning and hives (welts) under the rubber object. Some people experience itching and tearing eyes and, rarely, shortness of breath.
This is more common in people who wear tight fitting rubber gloves, such as medical workers. Rubber gloves may also cause dermatitis on the skin of the hands under the glove. Vinyl or synthetic gloves may be substituted. Many women with rubber allergy can wear undergarments with an elastic called spandex if they do not have rubber-backed fasteners or edges. Girdles and bras with no rubber are available.
Most cases of allergic contact dermatitis from shoes are caused by ingredients in the rubber used in the shoe’s construction. Adhesives, both rubber and non-rubber, can also cause problems. Even leather shoes may contain adhesives. Shoes without rubber should be substituted.
Hair Dyes
Most people can color their hair without difficulty. However, some are sensitive to paraphenylene-diamine (PPD). This ingredient is found in permanent hair dyes that are mixed with another chemical, such as peroxide, before application.
People allergic to PPD should not use any permanent hair dyes. About one-fourth of the people allergic to PPD are also allergic to ingredients in semipermanent dyes. Follow the package instructions for a patch test before using any hair dye.
Most PPD allergic people can use temporary dyes or rinses, to blend in gray and brighten hair. A few people, however, will react to these dyes too.
For more information on allergic contact allergies, please click here.
