Causes of Contact Dermatitis

Common causes of allergic and irritant contact dermatitis

Contact dermatitis is a rash that occurs on the skin due to something the skin has come into contact with. There are two categories of contact dermatitis: allergic contact dermatitis and irritant contact dermatitis. 

Allergic contact dermatitis is due to activation of the immune system in response to an agent that it comes into contact with, whereas irritant contact dermatitis is caused by direct irritation and damage to the skin by something it is exposed to.

In the United States, irritant contact dermatitis is seen more commonly than allergic contact dermatitis. People can encounter irritants in products they have in the home or in the workplace. Certain individuals are at an increased risk of irritant contact dermatitis based on their jobs and the materials they commonly use at work. For example, individuals working in the metal, rubber, and plastic industries commonly come into contact with cleaning materials, industrial chemicals, and paints that can be irritating. Individuals working as hairdressers, beauticians, and in the food industry can also be exposed to irritating substances while performing tasks for their jobs.

Both irritant contact dermatitis and allergic contact dermatitis can lead to a red, rough, itchy rash.

Irritant contact dermatitis and allergic contact dermatitis are most often diagnosed through history and physical examination of the rash.

Allergic contact dermatitis can further be diagnosed and/or confirmed through patch testing. Patch testing involves having small amounts of allergens taped to the skin. The skin is usually examined 48 hours later when the patches are removed, and then again 72-96 hours later. Patch testing can sometimes reveal an irritant contact dermatitis as well.

After patch testing, your physician can tell you what agents you reacted to and should thus avoid. Your physician may also provide you with a list of products that are safe for you to use.

Treatment of both irritant and allergic contact dermatitis consists of avoiding the offending trigger.  Topical agents may also be recommended or prescribed to treat these two types of rashes.  

Ten Common Causes of Irritant Contact Dermatitis

Animal Products​

  • Many products contain some substance that is derived from animals, and garments may contain animal furs that can cause irritant dermatitis.

Cosmetics

  • Cosmetics, such as perfumes, makeup, and hair products contain chemicals that can irritate the skin.

Degreasing Agents

  • Degreasing agents are substances used to remove grease from materials, typically during the manufacturing process of machinery and other industrial items.

Detergents

  • The acid, alkali, or antiseptic products in detergents can irritate the skin.  Additionally, other chemicals used in detergents can cause a reaction in the skin.

    Dust

    • Dust on objects or circulating in the air can cause an irritant contact dermatitis.

    Foods

    • The rinds and peels of fruits and vegetables contain oils that can irritate the skin during handling and consumption.

    Friction

    • Rubbing of the skin is irritating and can also hinder the ability of the skin to act as an effective barrier against other irritants.

    Solvents

    • Solvents that are acidic or alkaline can be very irritating to the skin.  Many industrial processes use solvents that can cause irritant dermatitis.

    Topical Medications

    • Topical medications can be irritating because of the active medication or due to other products in the topical formulation of a medication.

    Excess wetness or excess dryness

    • Prolonged wetness of the skin can be irritating and can also prevent the skin from acting as an effective barrier against other irritating substances.  Similarly, having very dry skin can cause cracking and removes important oils from the skin that allow it to protect against irritating substances.

    Ten Common Causes of Allergic Contact Dermatitis

    Bacitracin

    Balsam of Peru

    • Balsam of Peru is derived from the bark of a tree and is commonly found in body washes, perfumes, hair products, and moisturizers.

    Cobalt

    • Cobalt is a metal that has a blue color and is often used to cosmetics and blue tattoo pigment.

    Formaldehyde

    • Formaldehyde is a preservative and sanitizing material.  While formaldehyde itself is rarely used in the United States at this time, there are many chemicals that are used that degrade into formaldehyde (e.g. formaldehyde releasers including imidazolidinyl urea).

    Fragrance Mix

    • Fragrances are chemicals added to body washes, perfumes, hair products, and moisturizers.

    Gold Sodium Thiosulfate

    • Gold is often found in jewelry and can also cause oral contact dermatitis when gold is used in dental restorations.

    Neomycin Sulfate

    Nickel

    • Nickel is a metal used widely in jewelry, kitchen tools, stainless steel products, clothing, and medical devices.  Nickel is a common cause of contact dermatitis to earrings, belt buckles, and many other products.

    Quanternium 15

    • Quanternium 15 is a preservative that can be found in cosmetics, personal care products, and some metalworking materials.

    Methyldibromoglyaronitrile/phenoxyethanol

    • Methyldibromoglyaronitrile/phenoxyethanol is a preservative used in personal care products and industrial materials.

    Sources:

    Warshaw EM, Belsito DV, Taylor JS, et al. Contact Dermatitis Group Patch Test Results: 2009-2010. Dermatitis. 2013;24(2):50-59.

    Taylor JS, Amado A. Contact Dermatitis, and Related Conditions. Cleveland Clinic Foundation. http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/dermatology/contact-dermatitis-and-related-conditions/.  

    Allergy and Asthma Foundation of America: Contact Dermatitis. 

    Aakhus AE, Warshaw EM. Allergy to methyldibromoglutaronitrile/phenoxyethanol (Euxyl k 400): regulatory issues, epidemiology, clinical characteristics, and management. Dermatitis. 2011;22(3):127-140.

    Schalock PC. Common Allergens In Allergic Contact Dermatitis. In: UpToDate, Fowler J, Corona R, eds. http://www.uptodate.com/contents/common-allergens-in-allergic-contact-dermatitis?source=search_result&search=contact+dermatitis&selectedTitle=2~150. 

    Medline Plus: Contact Dermatitis. http://www.nlm.nih.gov/medlineplus/ency/article/000869.htm

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