Contact dermatitis
Created: 09.01.2025
Updated 09.01.2025
Approved by: Consultant Dermatologist, Dr James Denny
What is Contact Dermatitis?
Contact dermatitis is a common inflammatory skin condition that occurs when the skin comes into contact with a substance that causes a harmful reaction. It is a form of eczema and results from either direct irritation of the skin or an allergic response to a specific substance.
Contact dermatitis is distinct from atopic dermatitis, which is a chronic condition linked to genetic factors and a weakened skin barrier. However, people with atopic dermatitis are more prone to developing contact dermatitis because their skin is already more sensitive and easily irritated.
Contact dermatitis develops after exposure to an allergen or irritant. Common triggers include:
- Metals such as nickel, cobalt, and chromium
- Rubber and latex chemicals
- Fragrances, preservatives, and cosmetics
- Soaps, detergents, and cleaning products
- Hair dyes and topical medications
- Plants such as poison ivy or certain flowers
Repeated or prolonged exposure to chemicals and liquids, particularly in the workplace, can lead to occupational contact dermatitis, which is one of the most frequent work-related skin conditions.
What are the symptoms?
The symptoms of contact dermatitis vary depending on the trigger and the individual, but they usually affect the area of skin that came into contact with the substance.
Common symptoms include:
- Redness and inflammation
- An itchy rash, which may sting or burn
- Dry, cracked, or scaly skin
- Blisters, oozing, or crusting in more severe cases
- Swelling or tenderness of the affected skin
The skin reaction may be mild or severe. In long-standing cases, the skin can become thickened, rough, and painful due to repeated inflammation and scratching.
Contact dermatitis most commonly affects the hands, but it can occur anywhere on the body, including the face, neck, arms, and legs.
Types of Contact Dermatitis
Allergic contact dermatitis
This occurs when the immune system reacts to a specific allergen. Symptoms typically develop 24 to 72 hours after exposure and are often well defined, corresponding to the area of contact. Once the allergen is identified and avoided, the rash usually improves over days to weeks.
Irritant contact dermatitis
This is caused by direct damage to the skin barrier rather than an immune response. Symptoms can appear within minutes, hours, or after repeated low-grade exposure over time. The rash is often less clearly defined and more widespread. Irritant contact dermatitis is particularly common in people who frequently wash their hands or work with chemicals.
How is contact dermatitis diagnosed?
A dermatologist can usually diagnose contact dermatitis based on the appearance of the rash, its location, and a detailed history of exposures.
If allergic contact dermatitis is suspected, patch testing may be recommended. This involves applying small amounts of common allergens to the skin to identify which substance is causing the reaction. Identifying the trigger is essential to prevent recurrence.
What are the treatment options?
Avoidance and skin protection
The most important step in treating contact dermatitis is identifying and avoiding the trigger. Protective measures such as gloves, barrier creams, and changes in work practices are particularly important in occupational contact dermatitis.
Topical treatments
Topical corticosteroids are commonly prescribed to reduce inflammation, redness, and itching. The strength and duration of treatment depend on the severity of the rash and the area of skin affected.
Calcineurin inhibitors may be used in sensitive areas such as the face or when long-term treatment is required.
Skincare and symptom relief
Gentle skincare is essential. The skin should be kept clean but not over-washed. Fragrance-free moisturisers help repair the skin barrier and soothe irritated skin.
In more severe cases, additional treatments may be required to relieve severe symptoms, particularly if blistering, widespread inflammation, or secondary infection occurs.
Can contact dermatitis be prevented?
In many cases, contact dermatitis can be prevented by reducing exposure to known triggers.
Key steps to prevent contact dermatitis include:
- Avoiding known allergens once identified
- Using fragrance-free and hypoallergenic products
- Wearing protective gloves when handling chemicals or wet work
- Moisturising regularly to maintain a healthy skin barrier
- Taking extra care if you have a history of eczema or sensitive skin
What is the prognosis?
Contact dermatitis often improves once the offending substance is avoided, but recovery time varies depending on the severity of the reaction and how long the skin was exposed.
Irritant contact dermatitis usually resolves gradually with proper care, although repeated exposure can lead to chronic symptoms. Allergic contact dermatitis may recur if the allergen is encountered again, making long-term avoidance essential.
Although identifying the trigger can be challenging, most people achieve good control with accurate diagnosis, appropriate treatment, and consistent skin protection strategies.
Frequently asked questions
What is the difference between contact dermatitis and atopic dermatitis?
Contact dermatitis is caused by direct contact with an allergen or irritant, while atopic dermatitis is a chronic condition linked to genetic factors and a weakened skin barrier. People with atopic dermatitis are more prone to developing contact dermatitis because their skin is more sensitive.
What are the most common symptoms of contact dermatitis?
Common symptoms include redness, an itchy rash, stinging or burning, dry or cracked skin, and sometimes blisters or oozing. The reaction usually affects the area of skin that came into contact with the trigger.
How is contact dermatitis diagnosed?
Contact dermatitis is usually diagnosed based on the appearance and location of the rash and a history of exposures. If an allergic cause is suspected, patch testing may be used to identify the specific allergen.
How is contact dermatitis treated?
Treatment focuses on avoiding the allergen or irritant and reducing inflammation. Topical corticosteroids are commonly prescribed to calm the skin. Gentle skincare and regular moisturising help repair the skin barrier and relieve symptoms.
Can contact dermatitis be prevented?
In many cases, yes. Avoiding known triggers, using fragrance-free products, protecting the skin during wet or chemical work, and maintaining good skin hydration can significantly reduce the risk of developing contact dermatitis.
