What Is Contact Dermatitis?
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Medically reviewed by William Truswell, MD
Contact dermatitis is a skin condition that causes inflammation: rashes, redness, and itching. It occurs most frequently on the hands, but can also occur on the face and feet due to irritants such as certain metals, chemicals, or allergens, which cause an inflammatory reaction on your skin.
According to the Centers for Disease Control and Prevention (CDC), contact dermatitis can develop from chemicals and other substances you encounter daily. For example, soaps, cleaning chemicals, and gloves are common causes of contact dermatitis.
Contact dermatitis is one of the most common skin conditions. It can occur acutely, meaning it is a one-time event, or it may become a chronic condition. It is not contagious; you cannot catch it from someone or pass it on to someone else.
Types of Contact Dermatitis
Contact dermatitis is divided into several categories.
Irritant Contact Dermatitis
Irritant contact dermatitis (ICD) occurs when you encounter certain substances in your environment which irritate your skin and cause dry, itchy rashes where it touched it. The rash generally stays in the area that was exposed to the irritant. Irritant contact dermatitis (ICD) constitutes about 80% of content dermatitis cases.
You are more likely to develop ICD if you’re exposed to the substance for a long time or repeatedly, or there was a large or very concentrated amount of the substance. For example, washing your hands frequently with harsh soaps may lead you to develop ICD.
Other factors that determine the likelihood of developing ICD include:
Environmental factors: For example, very high or very low temperatures, humidity, etc.
Pre-existing conditions: For example, previous predisposition to allergic reactions.
Type of skin: For example, thick, thin, oily, dry, or very fair may be at risk for develop ICD.
Skin integrity: Previously damaged skin.
Allergic Contact Dermatitis
Allergic contact dermatitis (ACD) occurs when you encounter a substance that causes an allergic reaction on the skin it touches. You may develop ACD the first time you encounter the substance or after multiple times. For example, chemicals found in the workplace or rubber gloves can cause allergic contact dermatitis.
The rash will often begin a few hours after you come across the substance and is usually confined to the area that it touched.
Common allergens that may cause ACD include:
Corticosteroids
Plants, such as poison ivy
Metals, such as nickel in jewelry
Benzocaine used to treat itching
Fragrances, such as in perfumes or cosmetics
Chemicals, such as formaldehyde, latex, or hair dyes
Antibiotic ointments, such as neomycin and bacitracin
Latex gloves are a widespread source of ACD in the healthcare profession. ACD may start as a localized reaction on the hands, but it can develop into a more widespread (systemic) contact dermatitis or even an anaphylactic reaction (a severe, potentially life-threatening allergic reaction).
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Systemic Contact Dermatitis
Systemic contact dermatitis (SCD) occurs when an allergen creates a rash and itching that spreads beyond the area that came into contact with the allergen.
You may inhale the allergen, such as paint fumes or perfume, or ingest it, such as food. The rash or itching can occur anywhere on your body, and other non-skin-related symptoms may appear as well.
A history of ACD increases your chances of developing SCD if you inhale or ingest that substance or a similar one.
Photo Contact Dermatitis
Photo contact dermatitis occurs when the sun or other UV rays react with a chemical on your skin and causes an inflammatory reaction. The rash and itching are only confined to areas exposed to the sun.
For example, you may apply sunscreen liberally over your skin but only develop a rash on the sun-exposed areas of your body when you go outside.
Protein Contact Dermatitis
Repeated contact with specific proteins can cause protein contact dermatitis (PCD). The PCD rash is often on the tips of the fingers. It appears as a white area where the substance touched the skin and then a red area around the white, called a "wheal and flare" response. This is common in the food industry with people who handle food frequently.
Symptoms of Contact Dermatitis
Although itching is more common in ACD, irritant and allergic contact dermatitis share some common symptoms.
In the first stage of contact dermatitis, you may feel:
Tenderness
Blisters or pustules
Oozing
Itching
Redness
Scaling
Cracking skin
Pain
Burning
Blistering
Swelling in the skin
Stinging
Soreness
Rash
As the skin begins to heal, blisters or sores may begin to crust over, and you may see color changes.
If the dermatitis is recurrent, scratching the area can cause thickened skin, color changes, and exaggerated lines on the skin.
Irritant contact dermatitis symptoms begin within a few minutes to a few hours of contact with the irritant.
Allergic contact dermatitis may take up to three days to appear and may not reach its peak for three or four days. It progresses more slowly than ICD but tends to recur faster when re-exposure occurs.
With ACD, the severity of the reaction depends on:
The strength or concentration of the allergen
The sensitivity of the person or area exposed
How long the exposure lasted
Systemic contact dermatitis symptoms may include all the ICD and ACD symptoms, but the reaction will not be confined to just the skin that came into contact with the irritant or allergen. You may have a wide-spread rash anywhere on your body, often your hands, feet, buttocks, and inner thighs.
Other symptoms of systemic contact dermatitis are:
Diagnosing Contact Dermatitis
Your healthcare provider (HCP) will determine if your contact dermatitis is ICD or ACD by asking you questions about:
Your hobbies
Your medications
The timing of the symptoms
Potential workplace hazards
Patch testing is the gold standard to diagnose what is triggering contact dermatitis.
Your HCP will apply small patches of common allergens on your back. They will remove the patches in about two days and assess them for reactions after two or three days.
If a local reaction occurs under one of the patches, your healthcare provider knows that allergen is one of your triggers.
Treatment
Your healthcare provider may recommend some common treatments, such as:
Corticosteroid creams to reduce inflammation
Antihistamines to reduce and manage the itching
Immunosuppressive ointments, such as tacrolimus and pimecrolimus creams
They may also recommend simple treatments, such as:
Washing your hands with soap and water as soon as possible after exposure to known allergens or one that commonly affects people, such as poison ivy or poison oak
Avoiding tight-fitting clothes that may rub and irritate the area further
Unfortunately, it is very common for contact dermatitis to recur.
Prevention
You may prevent contact dermatitis with some simple habits:
Avoid known allergens.
If you work with an allergen, wear clothing that protects your skin from exposure, such as gloves or long sleeves.
Avoid tight-fitting clothes or other things that cause friction.
Avoid perfumes, dyes, and harsh soaps.
Apply lotions to keep your skin hydrated.
Avoid wearing jewelry or pick jewelry without nickel if you have a known allergy to nickel or are susceptible to allergies.
Read food labels and avoid known allergens.
Living With Contact Dermatitis
Contact dermatitis usually goes away without treatment. However, some treatments such as corticosteroids and antihistamines can make the condition more manageable. Talk to your healthcare provider about what treatments are available.
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