Contact allergens are the causative agents behind the occurrence of Allergic Contact Dermatitis or Contact Allergy. This common form of eczema is characterized by an allergic reaction prompted by the skin when it comes in contact with an allergen. Allergens are classified as any specific substance or material to which the skin is sensitive. However, allergens are individual-specific and are harmless to those that are not allergic to it. Contact allergies can also trigger eczema flare-ups. There have been various studies on what causes eczema flare-ups.
Symptoms of allergic contact dermatitis
Allergic contact dermatitis appears few hours after the individual comes in contact with the allergen. The common symptoms of contact dermatitis includes red, itchy, swollen and blistered or dry skin. The symptoms may subside over the next few days, if the affected person doesn’t come in contact with the responsible allergen again.
In most of the cases, contact allergy is restricted to the site that comes in contact with the allergen. However, in case of severe reactions, the infection may spread from the affected skin area to other body parts. E.g. from the fingers, the infection may be transmitted the eyelids and genitals.
Take into consideration that if the part of skin that came in contact with a specific allergen is unaffected and exhibits no allergic response, then eczema is not likely to be due to that allergen.
Some typical examples of allergic contact dermatitis include:
- A few people are sensitive to jewellery items and coming in contact with them initiates eczema. This is linked with allergy from nickel.
- A few people are allergic to the fragrances in perfumes and household items
- Dermatitis resulting from adhesive plaster, which is related to allergy arising from rosin.
- Permanent hair dye contains paraphenylene diamine that may cause allergic reaction in the form of swelling or blistering of face and neck.
- Manufacturing of rubber gloves makes use of rubber accelerator chemicals that causes hand dermatitis in few people.
- Methylisothiazolinone, a preservative used in wash-off hair products and baby wipes, may cause allergies in a few people and result in red, itchy face.
- Acrylates used in hair extensions and nail cosmetics may result in dermatitis on the fingertips.
- A few individuals may develop allergic reactions to metallic implants due to methyl methacrylate, benzoyl peroxide or gentamicin in bone cement.
- Acrylates used in dental implants may cause skin reactions.
- Localised blistering at the site of topical medications such as antibiotics
There is a long list of allergens/irritants that may result in Allergic Contact Dermatitis. The allergens causing skin reactions vary from an individual to individual.
According to the Mayo Clinic, the most recent list of top ten contact allergens include:
Top Ten Contact Allergens
- Nickel (nickel sulfate hexahydrate) — metal frequently encountered in jewellery and clasps or buttons on clothing
- Gold (gold sodium thiosulfate) — precious metal often found in jewellery
- Balsam of Peru (myroxylon pereirae) — a fragrance used in perfumes and skin lotions, derived from tree resin
- Thimerosal — a mercury compound used in local antiseptics and in vaccines
- Neomycin sulfate — a topical antibiotic common in first aid creams and ointments, also found occasionally in cosmetics, deodorant, soap and pet food
- Fragrance mix — a group of the eight most common fragrance allergens found in foods, cosmetic products, insecticides, antiseptics, soaps, perfumes and dental products
- Formaldehyde — a preservative with multiple uses, e.g., in paper products, paints, medications, household cleaners, cosmetic products and fabric finishes
- Cobalt chloride — metal found in medical products; hair dye; antiperspirant; objects plated in metal such as snaps, buttons or tools; and in cobalt blue pigment
- Bacitracin — a topical antibiotic
- Quaternium 15 — preservative found in cosmetic products such as self-tanners, shampoo, nail polish and sunscreen or in industrial products such as polishes, paints and waxes
The list above is retrieved from https://www.sciencedaily.com/releases/2006/03/060303204044.htm
How is allergic contact dermatitis diagnosed?
In most of the cases, it is easy to acknowledge the symptoms of contact allergy without the need to carry out any specific tests. However, in a few cases, tests are recommended by the dermatologist to diagnose the cause of allergic contact dermatitis.
Open application test is one of the diagnostic measures suggested to confirm if the allergy is as a result of cosmetic product like moisturizer. During the test, the individual is asked to apply the suspected product several times in a day to a small patch of sensitive skin. The treated skin is then tested for any reactions. In case, the reaction is severe, recurrent or chronic, the doctor performs patch tests to identify the allergen causing the reaction. E.g. Dimethylgloxime test is available to ‘spot test’ if a product contains nickel.
Currently, the most reliable method of identifying contact allergens is patch testing with a standard contact dermatitis series of substances.
Allergic contact dermatitis is a common skin condition that affects individuals of all age groups. It is necessary to treat the condition before it worsens and leads to severe reactions. Allergen avoidance is the best and chief method that one can adopt for treating contact dermatitis.