Types and Causes of Contact Dermatitis

Contact dermatitis is a form of dermatitis that occurs when the skin comes into contact with a substance that leads to irritation. This substance can either be an allergen that can cause an allergic reaction, or an irritant, which directly damages the skin.

Types of contact dermatitis

Approximately 80% of contact dermatitis cases are caused by irritants. There are two main types of contact dermatitis:

Types	Cause	Time for symptoms to develop
Irritant contact dermatitis	An irritating substance that directly damages the skin.	Within minutes to hours after exposure.
Allergic contact dermatitis	When a substance triggers an allergic reaction on the skin.	Within 24 to 48 hours after exposure.

Irritant contact dermatitis is more likely to occur in people with atopic eczema, the most common type of eczema.

Causes of contact dermatitis

Causes

Examples

Irritants

Substances that directly damage the skin’s outer layer. Examples:

Perfumes and preservatives in toiletries or cosmetics
Dust, powders, and soil
Soaps and detergents
Disinfectants
Antiseptics and antibacterials
Cement
Machinery oils
Acids and alkalis
Solvents
Water, specifically hard, chalky water or heavily chlorinated water

Allergens

Substances that trigger a reaction from the immune system. Examples:

Cosmetic ingredients: Fragrances, preservatives, nail varnish hardeners, and hair dye
Certain topical medicines: In rare cases, medicines applied directly to the skin, such as topical corticosteroids
Some plants: Poison ivy, tulips, sunflowers, primula, chrysanthemums, and daffodils
Textiles: Dyes and resins in them
Rubber: Includes naturally occurring types of rubber-like latex
Metals: Nickel or cobalt in jewellery
Strong glues: Epoxy resin adhesives

Symptoms of irritant contact dermatitis can get worse with exposure to friction (such as rubbing against the irritant), low humidity (dry air), heat, and cold.

Prolonged exposure to harmful chemicals or allergens can cause you to gradually develop chronic contact dermatitis symptoms, which may persist for many years.

Symptoms of contact dermatitis

Depending on the substance involved, the exposure duration, and the sensitivity of the individual, the symptoms can differ in appearance and intensity. Common symptoms include:

Redness	The affected skin often appears to be red and inflamed.
Itching	Intense itching which can result in increased irritation due to more scratching.
Rash	A rash commonly develops and often appears red, swollen, and blistered.
Dry, cracked, or scaly skin	Chronic contact dermatitis can lead to dry, cracked, and scaly skin.
Blisters	Small, fluid-filled blisters may form, and these can rupture, causing the development of crusts.
Swelling	Affected skin areas may become swollen.
Burning or stinging sensation	You may experience a burning or stinging sensation on the skin.
Tenderness or pain	It may become sore and painful to touch the afflicted area.

Diagnosis of contact dermatitis

Diagnosis of contact dermatitis combines physical examinations, medical history, and occasionally some specific tests to pinpoint the cause.

When allergic contact dermatitis is suspected, patch testing is frequently conducted. This involves applying small amounts of common allergens to the skin, usually on the back, with adhesive patches. The patches are kept in place for 48 hours before being taken off, and the skin is examined for allergic reactions at both the 48-hour mark and again between 72 to 96 hours. Signs of an allergic reaction may include redness, swelling, or small blisters.

Additional tests such as a skin lesion biopsy or a culture of the lesion, may be performed to exclude other possible causes.

Preventing contact dermatitis

One of the most effective ways to prevent contact dermatitis is to avoid the allergens or irritants that trigger your symptoms.

However, if avoiding contact is still not possible, you can still take precautions to reduce the likelihood of allergens or irritants causing symptoms.

Thoroughly wash your skin with soap and water as soon as possibleif your skin comes into contact with an allergen or irritant. If blisters have broken, apply cool, wet compresses to reduce inflammation. Avoid scratching the rash to prevent bacterial infection.

Wear gloves to protect your hands, but remember to remove them periodically, as sweating can aggravate your symptoms. If rubber irritates your skin, consider wearing cotton gloves underneath the rubber gloves.

Check the ingredients on your makeup or soap to ensure they do not contain any irritants or allergens; sometimes you may need to contact the manufacturer or fact-check online to retrieve specific information. You may need to stop using products that irritate your skin.

Review the ingredients in your make-up or soap. This is to make sure that they do not contain any relevant irritants or allergens. In cases that you need to confirm the details, information may be available either online or through contacting the manufacturer. Discontinue the use of any products that irritate your skin.

Apply emollients frequently and generously to keep your skin hydrated and help protect it from allergens and irritants. You may also opt for emollient soap substitutes in place of regular bar or liquid soaps, which are more likely to dry out your skin.

Book an appointment at Gleneagles Hospitals

If you notice that your contact dermatitis symptoms are getting worse or new ones are appearing, make sure to consult a doctor. The team of expert dermatologists at Gleneagles Hospitals is available for consultation, ensuring the best care and support for patients.

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