If you develop redness, swelling, cracking, blisters, or itchingon your skin when you come in contact with certain substances, youmay have “contact dermatitis” (CD) or a skin allergy. CD is causedeither by an allergy or a sensitivity/irritation to commonsubstances. 80% of skin reactions are caused by direct contact withan irritating product such as household cleaners, detergents andsoaps among others that can cause irritant CD in all exposedindividuals, especially with prolonged use.
What is Allergic Contact Dermatitis?
The skin is one of the first places where symptoms of allergycan appear. for people with a skin allergy or allergic CD, theimmune system overreacts to substances in direct contact with theskin, which are referred to as “allergens.”
Is Eczema the Same as Allergic Contact Dermatitis?
No. Eczema, also known as atopic dermatitis (AD), is a skindisorder that commonly affects children but can also occur inadults. although not all eczema cases are related to allergies,eczema tends to run in families, and people with eczema usuallyhave a family history of one or more allergic conditions such asasthma, hay fever, hives or seasonal allergies. People that sufferfrom eczema have cracked skin and a higher incidence of irritantand allergic reactions after coming in contact with variousproducts due to increased penetration through the diseasedskin.
What Causes Allergic Contact Dermatitis?
Exposure to chemicals found in many different products may causea skin allergy including detergents and cleaning products;sunscreens; hair, dental and baking products; plastic and glues;adhesive and surgical tape; and photography products. Otheroffending agents include:
Poison ivy (number one allergen), poison oak, poison sumac,other plants
Metals, such as nickel (very common allergen in metal buttons,cheap jewelry, watches, zippers, kitchen utensils, etc)
Fragrances, perfumes (soaps, deodorants,
body creams, cosmetics, scented toilet paper, etc)
Dyes for hair, clothing, leather, furs
Preservatives (shampoos, cosmetic products,topical medications,etc)
Nail care products (nail polish remover, hardeners, etc)
Rubber compounds (waistbands, gloves, bras, condoms, etc)
Medications, including topical antibiotics, steroid creams andtopical anesthetics
An allergic CD occurs gradually over time after repeated use ofa substance. once that threshold is crossed, the individualdevelops a specific sensitivity so even brief contact with thatallergen may cause allergic contact dermatitis to reappear within24-48 hours. some products cause a reaction only when the person isexposed to sunlight after the contact with the substance(photo-contact dermatitis). these commonly include sunscreens,shaving lotions, topical antibiotics, perfumes, coal tar, and limejuice. A few airborne allergens such as ragweed or insecticidespray can also cause allergic contact dermatitis on the exposedareas. Often the offending substance(s) can be “obscure” componentsof a product, so be sure to carefully read labels. Even productsmarked as “hypoallergenic” can still contain fragrances and“unscented” products may contain small amounts of fragrance used tomask unpleasant odors.
What are the Symptoms of Contact Dermatitis?
Symptoms of CD range from mild to severe and include red, itchy,swollen, and warm skin, sometimes accompanied by oozing orblistering. Peeling of skin may follow. Symptoms usually appear onthe areas that were in contact with the offending substance(s).
How is Allergic Contact Dermatitis Diagnosed?
The gold standard for diagnosing CD is “skin patch-testing,”which identifies the substances suspected of causing the allergy.Patch testing requires three office visits. A complete physical anddetailed history helps the specialist tailor specific patch testsfor each patient. On the first visit, small patches of potentialallergens are applied to upper back skin. these patches are removed48 hours later to evaluate for a reaction. A third visit 1-2 dayslater assesses late reactions. Patients should also bring alongsuspected materials for testing in addition to the standardizedpatch tests.
Topical corticosteroids or in severe cases oral steroids areneeded to alleviate the redness and itching.
CD usually clears without complications within several weeks,but may recur if the offending substance cannot be identified orremoved. A change of occupation or occupational habits may benecessary if the disorder is caused by occupational exposure, whichcan affect hairdressers, dentists, florists, and many others.
Avoid contact with suspect materials. If contact is unavoidable,use protective gloves or other barriers and wash skin surfacesthoroughly with soap and water after contact.
Who will benefit from patch testing? Patients with: (1)long-standing, recurring skin rash, with an unknown cause, (2)atopic dermatitis/eczema, (3) sensitive skin, that cannot tolerateskin contact with cosmetic products, (4) exacerbation in theirrashes after use of topical medicaments, (5) hand dermatitis, (6) asuspected dermatitis due to occupational exposure, and (7) a rashin a sun-distributed area. If you suspect a skin allergy, ask yourdoctor to refer you for extensive patch testing to a specializedcontact dermatitis clinic. Patch tests should be done only bydermatologists who specialize in these procedures. Most healthinsurers cover extensive patch tests which might benefit manypatients with long-standing skin rashes or eczema.
Emma Guttman, MD, PhD
Assistant Professor of Dermatology & Immunology
Director of Occupational and Contact Dermatitis
Director of the Laboratory of Inflammatory Skin Diseases,Department of Dermatology
To schedule an appointment call (212) 241-9728 or visit theon-line registration at www.MountSinaiDermatology.com