Frequently Asked Questions About Contact Dermatitis

Two types of common contact dermatitis exist: allergic and irritant. Allergic contact dermatitis occurs when a person with an allergy or sensitivity to a substance comes into physical contact with it. The most common cause of allergic contact dermatitis is poison ivy, as upwards of 70% of the U.S. population has a sensitivity to poison ivy or poison oak.

Irritant contact dermatitis describes dermatitis that develops following exposure to chemical or physical agents or microtrauma. Physical irritants include friction or abrasion. Experts will sometimes further classify the irritants themselves into different categories. For example, if a person experiences hydrofluoric acid exposure, that is a toxic irritant.

Other forms include subtoxic, degenerative, or cumulative—such as hand soap leading to irritant dermatitis in hospital staff.

Everyone is at risk of developing allergic contact dermatitis, though what they may react to varies depending on individual sensitivities. A few populations are far more susceptible to irritant contact dermatitis. These groups include women, infants, older adults, and people with a history of atopic dermatitis. Experts believe the higher rate in females is likely due to more frequent use of jewelry and fragrances.

Additionally, people with jobs that require frequent exposure to chemicals have a much higher occupational risk of irritant contact dermatitis. Overall, contact dermatitis is most common in people with fair skin and red hair.

The symptoms of both forms of contact dermatitis are similar and share progression. Early on, the symptoms include swelling, tenderness, oozing blisters, and dryness.

Along with these symptoms, many people experience itching, burning, stinging, pain, or soreness. Over time, the rash worsens and forms scales, crusts, and hyperpigmentation. If a person has chronic contact dermatitis, their skin may undergo lichenification, which is when the skin becomes thick and leathery with exaggerated cracks, wrinkles, and scales.

Contact dermatitis can affect any area of the body, depending on which region came into contact with the irritant or allergen. The hands are the most common location of contact dermatitis. Hikers may notice contact dermatitis on their legs after brushing against poison ivy or a similar plant.

People with metal allergies can develop rashes on regions that frequently touch metal, such as the neck, wrists, fingers, ears, and stomach. Rashes may develop within minutes of exposure, but it could take hours. Depending on the severity, contact dermatitis can take up to a month to fully vanish.

A simple clinical examination can lead to a diagnosis of contact dermatitis. The doctor will ask questions about when the rash developed, as well as what their patient does for work and hobbies. Often, this line of questioning reveals exposure to an irritant.

If a physician suspects allergic contact dermatitis, they may perform a patch test. By applying patches that can trigger common allergic reactions, doctors can figure out which substance is responsible.

Once the skin no longer comes into regular contact with the triggering substance, contact dermatitis will slowly heal on its own. To aid in the recovery process, avoid scratching any irritated skin. Use mild soap and lukewarm water to clean the area and remove any irritants.

Cool compresses and over-the-counter antihistamines can help with itchiness and pain. A doctor may prescribe a topical or oral corticosteroid to improve symptoms.

Staying away from common irritants and known allergens is the best way to prevent contact dermatitis. People prone to this condition should use fragrance-free moisturizers and mild, scent-free soaps.

When working with potential irritants, wear protective gear at all times. Immediately wash the affected area after any contact with an irritant or allergen.

Though rare, contact dermatitis complications are possible. Allergic contact dermatitis is a hypersensitivity reaction that occurs through a different mechanism than conditions like hives or anaphylaxis. However, a small number of people experience multiple hypersensitivity reactions at once, resulting in allergic dermatitis overlapping with life-threatening conditions like anaphylaxis. This requires immediate medical intervention and epinephrine injection.

See a healthcare professional if the contact dermatitis rash:

• Itches constantly
• Begins to blister or develop pustules
• Vanishes and then returns
• Develops an infection
• Is painful
• Does not improve after a week of treatment

Immediately contact a medical professional if the rash begins to spread or if other symptoms develop, such as difficulty breathing, nausea, or fever.