Contact Dermatitis

If you’ve ever been out hiking in the woods, you probably know to avoid certain plants: poison oak, poison ivy, and poison sumac, for example. They’re all off-limits, unless, of course, you want to suffer from a painfully itchy rash.

Cooks, hair stylists, doctors, nurses, orderlies, or those working in any type of cleaning service know how rough the chemical and conditions at work can be on their skin.

Why is it that certain plants and substances cause these agonizing skin reactions for certain people? The red, inflamed reaction is technically called contact dermatitis. In essence, it’s the skins reaction to coming into contact with something it finds annoying.

If you experience skin inflammation when you touch something like a plant or metal, it is contact dermatitis.

There are two types of contact dermatitis: irritant and allergic.

Irritant Contact Dermatitis

The majority of contact dermatitis cases are the irritant type. This type happens when substances (soaps, solvents, fiberglass, etc.) directly injure the skin. While this type normally affects the hands and forearms, it can occur in any part of the body that comes into contact with the irritating substance.

Jobs that require frequent exposure to heat and water—such as food preparation, dishwashing, and hair styling—can make skin more prone to irritant contact dermatitis.

Allergic Contact Dermatitis

Allergic contact dermatitis occurs when your body’s immune system reacts to an allergy-causing substance. Dermatitis can also be atopic, meaning it comes from a hereditary tendency towards excessive Immunoglobulin E (IgE) reaction. Atopic dermatitis is also called "eczema."

Skin allergies affect up to one-quarter of Americans at some point in their lives. Those allergies have a variety of causes, and produce similar—but often subtly different—rashes and other symptoms.

What Are Allergies?

An allergic reaction happens when your immune system has an overblown response to a substance that isn’t normally harmful.

Typically, our immune systems respond to dangerous external elements by producing groups of cells known as Immunoglobulin E (IgE) antibodies. These antibodies normally protect us from harmful irritants and toxins, like bacteria and viruses, which can cause infections and other illnesses. 

Basically, antibodies in the immune system are the body’s security guards. For those with an allergy, however, that security works too hard.

When an allergic reaction occurs, the immune system is overly sensitive to certain substances, thinking they are harmful even though they are actually harmless. This sensitization triggers an inflammatory response sparked by the release of IgE and eosinophils (white blood cells produced in the blood marrow) and other cell types. They start attacking because they perceive a threat to the body, when in all actuality there is no threat at all.

What is an Allergic Reaction?

A true allergic reaction cannot occur without an initial exposure to an allergen, sensitization (when IgE is previously induced by that exposure), and then another exposure.

Most of the time, reactions are mild, with site-dependent symptoms such as a skin rash, hives, itchiness, or swelling. Occasionally, however, an allergic reaction can produce a more challenging and dangerous outcome—anaphylactic shock, for example, which is an emergency situation during which breathing can become difficult and blood pressure can drop precipitously. Anaphylactic shock is almost never caused by skin allergies.

Treating allergic reactions has become somewhat more effective with powerful drugs introduced over the past several years. The best strategy by far, though, is prevention—staying away from known allergens in order to keep irritation and even more significant symptoms from developing in the first place. Without doubt, preventing symptoms by eliminating exposure to allergens is the gold standard for allergy control.

Symptoms of Contact Dermatitis

As skin reacts to either allergens or irritating substances, it can cause an array of symptoms on the affected skin.

While the two different types of contact dermatitis—irritant and allergic—have different causes, they often cause similar symptoms, such as:

  • redness
  • tenderness
  • itching
  • dryness
  • flaking
  • scaliness
  • skin thickening
  • feeling of warmth
  • oozing
  • blistering
  • lesions (in extreme cases), including papules (pimple-like)
  • swelling on the top layer of skin (epidermis)
  • swelling of deeper layers of skin, often in the eyelids, mouth, or genitals

Skin allergy symptoms usually appear one to three days after contact with the allergen.

Hives may be a result of a food or drug allergy, but they are also common from contact with latex. This is a particularly prevalent allergy among health care workers who often use latex gloves.

Irritant contact dermatitis often appears similar to a sun burn: red, swollen, and itchy skin.

Causes of Contact Dermatitis

There are many types of chemicals and substances that can cause contact dermatitis.

Irritant contact dermatitis is caused by contact with acids, alkaline materials, and other chemicals found in fragrances, preservatives, and household items like soaps, detergents, and solvents. It can also be caused by other harsh chemicals.

Allergy contact dermatitis can be triggered by one of more than 3,700 identified allergens. However, fewer than 40 of these allergens cause the majority of cases of contact dermatitis.

Poison ivy, oak, and sumac are the best-known plants that cause allergic reactions. Other allergens often associated with contact dermatitis are:

  • adhesives
  • cleansers
  • contact lens solution
  • cosmetics
  • detergents
  • dyes (for clothes, leather, cosmetics, or hair)
  • fiberglass
  • first-aid ointments or creams containing neomycin or bacitracin
  • formaldehyde
  • fragrances
  • gasoline
  • leather tanning agents
  • metal (especially nickel) jewelry
  • motor oil
  • nail polish remover
  • paints
  • preservatives
  • rubber (in clothing, shoes, gloves, etc.), especially latex
  • shampoo
  • soaps
  • sunscreen
  • toothpaste
  • varnishes

Treatments for Contact Dermatitis

Treatment of contact dermatitis should begin with washing the skin using copious amounts of soap and water after contact with a known allergen. Even washing the skin within 15 minutes of exposure to poison ivy can prevent the rash from developing.

In some cases, doing nothing to the area is most beneficial. This can prevent further inflammation and spreading of the allergen across the skin.

Home Treatments

Contact dermatitis can be treated easily at home using the following treatments:

Cool compresses

Applying a cool, damp cloth to the affected area can help control inflammation and help control itching sensations.

Over-the-counter ointments or lotions

Anti-itch creams that contain aloe or calendula, natural ingredients that are anti-inflammatory agents, can ease itchiness and control inflammation. Some popular OTC brands include Aveeno, Cortizone-10, Lanacane, Gold Bond, and Caladryl.

Antihistamines

If your contact dermatitis is caused by allergens, you might benefit from over-the-counter antihistamines, such as Benadryl or store-brand allergy medication.

Lukewarm baths

Baths with oatmeal or medicated solutions (such as saline) are also recommended, especially for children.

Doctor’s Prescriptions

If your contact dermatitis is severe enough, your doctor may prescribe corticosteroid skin creams or ointments to reduce inflammation. Steroid creams are very common for people with skin conditions, and are often available in low-dose, over-the-counter strengths. It’s important to follow the directions of the medication because misuse can lead to more serious skin conditions. 

Along with, or instead of, corticosteroid skin treatment, your doctor could prescribe you tacrolimus ointment (Protopic) or pimecrolimus cream (Elidel) to treat the symptoms of the rash, such as redness, scaling, and itching.

Experienced allergists or internists will also opt, in some cases, to do nothing to the affected area. This will depend on the doctor’s close examination, which may indicate that any treatment or medication could actually cause more problems than relief.

Contact Dermatitis Prevention

The best approach to preventing contact dermatitis is avoiding the substance that causes you skin rashes or other reactions.

Prevention at Home

Once you and your doctor has identified what substances or activities caused your initial outbreak, it’s important to avoid those substances in the future. If you know there’s something to which you are allergic, make sure to read all labels on cosmetics, lotions, soaps, and other products that will regularly come in contact with your skin.

To prevent contact dermatitis, some people may need to switch to dye- and perfume-free soaps, detergents, and other household products.

Prevention at Work

Often, however, avoidance is impossible in workplace environments. Protective gear—gloves, shirts, a mask, etc.—are necessary to reduce the chance of contact with the allergen. This could include:

  • using non-latex protective gloves
  • wearing long sleeve shirts
  • using good ventilation
  • using barrier creams or skin cleansers
  • good personal hygiene
  • properly storing chemicals
  • using disposable paper towels

If you cannot avoid substances that irritate your skin, washing the affected area immediately with warm water and mild soap can help contain your skin’s reaction.