Causes and Risk Factors of Contact Dermatitis

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Contact dermatitis is an itchy, blistering skin rash typically caused by skin's direct contact with a substance. In the irritant type of contact dermatitis, the most frequent triggers are chemicals such as in soaps, bleach, dyes, and solvents. In allergic contact dermatitis, common allergens include nickel, adhesives, plants, cosmetics, and topical medications.

Narrowing the list of things you think may be causing your rash can help your doctor make a formal diagnosis and provide you with strategies for avoiding such a reaction in the future.

Common Causes of Contact Dermatitis
Verywell / Cindy Chung

Common Causes

Obviously, finding what is triggering your contact dermatitis is essential to avoiding reactions. These are the most frequent irritants and allergens.

Nickel

Nickel is the most frequent cause of allergic contact dermatitis. Between 8% and 11% of women have this allergy.

Nickel is not only found in jewelry, but also in zippers, bra hooks, buttons, coins, and common metal objects. Other metals can also cause allergic contact dermatitis, including cobalt and chromium salts.

Occupational Exposures

The most common jobs associated with contact dermatitis include healthcare professions (usually due to a latex allergy), food handlers and processors, beauticians and hairdressers (due to hair dyes and other treatments), machinists, and construction workers. 

The hands are the most likely body part to be affected by contact dermatitis. Among the most common agents that cause occupational contact dermatitis are:

  • Carba mix
  • Thiurams
  • Epoxy resin
  • Formaldehyde
  • Nickel

Occupational skin conditions are second only to traumatic injuries as the most common cause of job-related health issues. Approximately 40% of worker's compensation cases involve skin problems, and up to 95% of these involve job-induced contact dermatitis.

Plants

Plants from the Toxicodendron family, which include poison ivy, poison oak, and poison sumac, are the most common cause of allergic contact dermatitis. The rash from these plants results in a linear, or streak-like group of itchy blisters or bumps.

The chemicals released from the plants, called urushiols, are what cause dermatitis. Urushiol can be carried on the fur of animals, garden tools, sports equipment, and clothing. The smoke from burning Toxicodendron leaves can also carry urushiol.

Elements of other plants related to Toxicodendron may contain urushiol and cause contact dermatitis as well. These include mangoes (skin), cashew nuts (oil), and gingko leaves. 

Patch testing is not necessary for Toxicodendron plants since this diagnosis is made with a consistent history and physical examination. Most people know when they've come in contact with poison ivy or one of its relatives within a short time after being exposed.

Other causes of plant contact dermatitis include contact with the Peruvian lily, a common cause of hand dermatitis in flower workers, as well as seasonal contact dermatitis from exposure to airborne pollens. Patch testing may be performed in dermatitis caused by these plants.

Cosmetics and Personal Care Products

Cosmetic-induced contact dermatitis is very common, since people may apply numerous chemicals to their skin, hair, and scalp on a daily basis.

Typically, the rash will occur on the skin where the product was applied, although sometimes the rash will occur on another part of the body that comes in contact with that area.

Fragrances appear to be an important and common cause of contact dermatitis. Not only are fragrances found in perfumes, but also in personal care products such as soaps and bath products.

Rashes can appear on the neck in a pattern consistent with product application. Patch testing with a fragrance mix can help identify the cause and provide important information on avoidance.

Avoiding fragrances can be difficult, and use of products labeled “unscented” can be misleading, as a masking fragrance may be added. It is better to use products labeled as “fragrance-free”, which are typically tolerated by people with fragrance-induced contact dermatitis.

Lotions: Aside from the fact that many lotions contain fragrance as well, some may have lanolin, which may cause a reaction in some.

Hair products are another common cause of contact dermatitis. Common chemicals include phenylenediamine in hair dyes, cocamidopropyl betaine in shampoos and bath products, and glyceryl thioglycolate in permanent wave solution.

Sunscreens and sunblocks, also commonly found in various moisturizers and cosmetics, can result in facial contact dermatitis, with or without activation by sunlight. Para-aminobenzoic acid (PABA), found in some products, may be the culprit. Some of the “chemical-free” sunscreens, containing physical blocking agents such as zinc oxide and titanium dioxide, are better tolerated by people with sunscreen-induced contact dermatitis.

Reactions to acrylic coatings on fingernails are a common cause of contact dermatitis on the fingers, as well as on the face and eyelids. Many people who use cosmetics on their fingernails (artificial nails or coatings on natural nails) may touch their face and eyelids with their nails. Common chemicals include acrylates and formaldehyde-based resins.

Topical Medications

Numerous topical medications can result in contact dermatitis when applied to the skin. These include:

  • Topical antibiotics, such as Neosporin (neomycin) and bacitracin
  • Anti-itch creams containing local anesthetics
  • Topical corticosteroids, such as hydrocortisone cream
  • Topical non-steroidal anti-inflammatory drugs (NSAIDs), such as Aspercreme

Oral and Dental Products

Reactions involving the tongue, gums, mucous membranes, lips, and skin around the mouth can be related to various dental and oral products. The resulting contact dermatitis can be due to:

  • Metals from dental work (mercury, chromium, nickel, gold, cobalt, beryllium, and palladium)
  • Flavorings in toothpaste, mouthwashes, or chewing gums (Balsam of Peru, cinnamic aldehyde, and others)
  • Foods from the Toxicodendron family
  • Lipsticks or lip balms

Surgical Implant Devices

While reactions to metal surgical implant devices are often suspected, reactions to the implants are rarely proven.

If such reactions occur, symptoms can include rashes (either over the site of the implant or generalized) and loosening of the implant. This may be due to the metal in the device itself or acrylic glues used with such hardware.

For people with a history of metal allergy, patch testing with the metals found in the implant device prior to surgery may help identify whether they are likely to react, and a non-allergenic substitute may be made.

Systemic Contact Dermatitis

Systemic (or whole-body) contact dermatitis can occur as a result of medications, chemicals, and foods. In these cases, a person first has a sensitization due to contact with the skin and then may react to the same or similar compounds in food, drink, or medications taken orally, inhaled, or through other non-skin routes.

Systemic contact dermatitis has been seen after the administration of intravenous aminophylline (sometimes used to treat severe asthma). A systemic reaction has been seen in people sensitive to nickel if they drink tap water with nickel traces or eat foods prepared with nickel utensils. Some fragrance-sensitive people may react to citrus fruits or certain spices.

Genetics

There appears to be some genetic predisposition to contact dermatitis, as some people are more prone to develop allergies to chemicals, while others with the same exposure do not.

But there are many systems at play that determine whether or not you develop the allergy or an irritant reaction. These include how well your skin acts as a barrier, how your body produces an inflammatory response, and how prone you are to developing allergies.

While some genes have been proposed as increasing your risk, there are no definitive culprits.

Contact dermatitis results in 5.7 million doctor visits each year in the United States, and all ages are affected. Females are slightly more commonly affected than males, and teenagers and middle-aged adults seem to be the most common age groups affected.

Lifestyle Risk Factors

You are more at risk of developing contact dermatitis if your job, hobbies, or household products bring you in frequent contact with common irritants and allergens. Be sure to wear protective clothing or gloves whenever you handle cleaning products or other chemicals. If you have contact with an irritant, wash your skin as soon as possible with fragrance-free soap and warm water.

Using fragrance-free hand moisturizer and skin moisturizer can help keep your skin healthy and intact, which may prevent the irritant from triggering a dermatitis reaction.

Learn to recognize poison oak, ivy, and sumac so you can avoid them. Not only do these grow in natural areas, in many places, they grow as weeds in your yard, garden, or on the roadside.

A Word From Verywell

The location of a contact dermatitis rash is often a significant clue about its cause. Be sure to make a list of what you suspect when you see your doctor for a diagnosis. The evaluation for contact dermatitis includes patch testing and your history of exposure to various chemicals. Once you know what triggers your contact dermatitis, avoiding that substance will be a key part of treatment and prevention.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Fonacier L, Bernstein DI, Pacheco K, et. al. Contact dermatitis: A practice parameter update 2015. J Allergy Clin Immunol Pract. 2015 May-Jun;3(3 Suppl):S1-39. doi:10.1016/j.jaip.2015.02.009.

  2. Lampel HP, Silvestri DL. Systemic contact dermatitis: Current challenges and emerging treatments. Curr Treat Options Allergy. 2014; 1: 348. doi:10.1007/s40521-014-0029-6

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