Allergic Contact Dermatitis: An Overview

Though uncomfortable, this rash is typically harmless.

Allergic contact dermatitis is a delayed hypersensitivity skin reaction that occurs after you touch a substance that you are allergic to.

For example, allergic contact dermatitis might occur when a person who is allergic to latex wears latex gloves. Though they do not notice any change in their skin right after taking the gloves off, a red and itchy rash develops on their hands the next day.

Latex along with metals and personal care products are common allergic contact dermatitis triggers. While not harmful, allergic contact dermatitis occurs in stages and usually results in a very itchy, red rash that may have scaling, cracking, blistering, and lichenification (thick, leathery skin patches).

Allergic contact dermatitis accounts for 20% of all contact dermatitis reactions.

Allergic Contact Dermatitis Symptoms

Laura Porter / Verywell

Symptoms

The symptoms of allergic contact dermatitis can include:

  • A raised, red rash
  • Itching
  • Small blisters, which may pop and drain fluid (vesicles)
  • Dry, scaly patches
  • Areas of cracked skin (fissuring)

The shape and location of the rash are important clues to the cause of the allergen. For example, the pattern of the rash caused by a reaction to metal will often correspond exactly to the shape of the offending item, such as a watch or a ring.

Symptoms of allergic contact dermatitis can occur within a few hours of coming in contact with an offending substance, or they can arise up to several days later. Symptoms may persist for several weeks, even after the substance has been removed.

Lichenification can occur in chronic cases of contact dermatitis. Lichenified skin looks thick and leathery. The patches are dry and darker than the surrounding skin. Lichenification develops when an area of skin is repeatedly scratched over a long period of time.

Causes

Like any allergy, one that gives rise to allergic contact dermatitis is due to the immune system treating a harmless substance as something it needs to defend against. Just as you may sneeze if you are allergic to pollen and smell some flowers, you may break out in an allergic contact dermatitis rash if you are allergic to, say, preservatives and use cosmetics made with them.

Some of the more common substances that trigger allergic contact dermatitis include:

  • Metal, especially nickel and chromium: These metals are found in many costume jewelry pieces, belt buckles, and clothing closures (including the backs of buttons on jeans).
  • Rubber or latex found in items like gloves, condoms, balloons, and shoes.
  • Fragrance in cosmetic products: This includes fragranced soaps, perfumes, shampoos, and lotions.
  • Preservatives used in cosmetic products: Common offenders include quaternium-15, DMDM hydantoin, formaldehyde, and isothiazolinones.
  • Sunscreen products: The active ingredient oxybenzone, found in many sunscreens, is a common cause of photoallergic contact dermatitis (i.e., an allergic skin reaction that occurs only after you are exposed to both an allergen and the sun).
  • Poisonous plants, such as poison ivy, poison oak, and poison sumac
  • Adhesives: For example, those used in non-stick bandages and medical adhesive tape, glue used to apply false eyelashes, or tape used to for wigs.
  • Topical medications: Both topical over-the-counter and prescription medications can trigger reactions. Triple-antibiotic ointments (like Neosporin which contains the contact allergen neomycin) can be problematic.
  • Balsam of Peru: A common ingredient in cosmetics, as well as food and drinks.

A skin reaction to something that you are not actually allergic to is called irritant contact dermatitis. With this type, there is no immune response to the substance, unlike with allergic contact dermatitis.

Stages of Allergic Contact Dermatitis

Allergic contact dermatitis has two distinct stages: the sensitization stage and the elicitation stage. The sensitization stage is when the skin first comes in contact with the offending substance. The elicitation stage is when the symptoms appear.

Sensitization Stage

During this stage, an antigen comes in contact with the skin. Because most of the antigens that cause this type of reaction have a low molecular weight, they can easily penetrate the outer layer of the properly functioning epidermis.

The antigen is processed by cells in the basal layer of the epidermis and then presented to white blood cells called T lymphocytes. These T lymphocytes recognize the antigen as foreign and circulate through the bloodstream back to the epidermis.

Elicitation Stage

The elicitation stage occurs in sensitized people who are re-exposed to the antigen. The T lymphocytes in the epidermis once again recognize the antigen as foreign, this time producing inflammatory chemicals designed to eradicate the antigen.

It is these chemicals that produce the characteristic skin rash.

Can contact dermatitis spread if you scratch it?

Scratching at an allergic contact dermatitis rash can cause the inflammatory chemicals that triggered the rash to spread. As a result, your rash can become more inflamed, irritated, and widespread. Allergic contact dermatitis is not contagious from one person to the next, however.

When to See a Healthcare Provider

If you are concerned about your symptoms or have a rash that won't seem to go away, go ahead and contact your healthcare provider.

If you know what is causing your reaction and you are able to avoid it, the rash should go away within about 10 days—so long as you don't scratch at it.

Other reasons you should reach out to your provider include:

  • You have a fever or your skin has signs of infection, such as blisters that ooze cloudy or yellow pus.
  • The rash is growing more widespread or getting worse.
  • The reaction is on your face or genitalia.
  • Your symptoms are preventing you from sleeping or interfering with your day.

If your provider suspects that you are dealing with allergic contact dermatitis, they may refer you to an allergy specialist.

Allergic Contact Dermatitis Complications

The most common complication of allergic contact dermatitis is a bacterial infection. Scratching at your rash or blisters can cause bacteria to infect your skin. Avoid this complication by not scratching and keeping any open blisters clean by using a mild, fragrance-free soap and water.

Diagnosis

Your healthcare provider will examine your rash and, if they suspect contact dermatitis, will ask for a detailed history. Your healthcare provider may ask about your job, your hobbies, and your home life to help determine which substances may be triggering your rash, if any.

Patch testing is often done to identify allergens. This is a simple procedure in which small amounts of common allergens are placed on your back with an adhesive sheet. After 48 hours the patches are removed and the skin checked for allergic reaction. Another reading of the skin is done approximately two days later.

Patch testing is painless, although you may have some itching or irritation if you have a positive reaction to any of the patches. Knowing your potential triggers will help you can avoid these substances going forward.

It can be difficult to tell allergic contact dermatitis from other types, such as irritant dermatitis or atopic dermatitis (eczema), as the rashes they produce are similar. It's best to seek a professional opinion if you experience a rash so that you can get a proper diagnosis and the correct treatment.

Allergic Contact Dermatitis Treatment

The mainstay allergic contact dermatitis treatment is avoiding the offending allergen (if one can be determined).

Over-the-counter (OTC) hydrocortisone creams can be used if your rash is mild or covers a small area. Apply up to four times per day, or as directed on the product packaging, and rub in gently but completely. Don't use OTC hydrocortisone on babies or young children without first talking to a pediatrician.

Prescription topical steroids may be needed for more severe rashes. These will help reduce inflammation and itching. When used as directed, these are very safe and effective treatments.

Oral steroids, such as prednisone, may be prescribed in very severe cases, or where the rash covers large areas of the body.

Other helpful measures to consider, especially if the allergen cannot be identified, include:

  • Minimize the topical products you're using: This reduces your exposure to potential allergens and allows the skin to heal. You may want to use plain water rather than soap and avoid make-up and perfumes altogether.
  • Use ointments instead of creams: Ointments, such as Eucerin or Aquafor, form an occlusive barrier over the skin that can ease discomfort.
  • Avoid botanical extracts found in "fragrance-free" or "natural" products, as these can be very allergenic. Also, some home remedies (e.g., herbal poultices, essential oils) may exacerbate inflammation, so use them only with your healthcare provider's OK.
  • Be on the lookout for hidden allergens: For example, earring posts may be made of sterling silver or gold, while the backs are made of nickel.

Prevention

If you know what is triggering your allergic contact dermatitis, then the best thing you can do to prevent a reaction is to avoid the allergen. Take care to read labels on any product you wear or apply to your skin and ensure the allergen isn't included.

If you are not sure what is triggering your reaction, you can start by avoiding common dermatitis triggers, including jewelry containing nickel and latex, and cosmetic products that contain fragrances or dyes, such as hair dyes.

It can be very helpful both for you and your healthcare provider to keep a journal about your symptoms. If you notice a reaction is beginning, write down which products you recently used near the affected area of your skin. Bring any findings and suspicions to your provider's attention.

A Word From Verywell

Allergic contact dermatitis is a common problem. While it's harmless, it can be uncomfortable enough to affect your daily life (and especially your ability to sleep). It may or may not be immediately clear what has triggered your rash, so work with your healthcare provider to identify your triggers so you can do your best to avoid them. Patch testing, plus a bit of detective work, can help.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Zukiewicz-Sobczak WA, Adamczuk P, Wróblewska P, et al. Allergy to selected cosmetic ingredients. Postepy Dermatol Alergol. 2013 Oct;30(5):307-10. doi:10.5114/pdia.2013.38360


  2. Novak-Bilić G, Vučić M, Japundžić I, Meštrović-Štefekov J, Stanić-Duktaj S, Lugović-Mihić L. Irritant and allergic contact dermatitis - skin lesion characteristics. Acta Clin Croat. 2018 Dec;57(4):713-720. doi:10.20471/acc.2018.57.04.13

  3. Yale Medicine. Allergic contact dermatitis.

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