Contact dermatitis is a common skin condition that occurs when the skin comes into contact with a substance that causes an inflammatory reaction. There are two main types of contact dermatitis: irritant and allergic. This article will explain the causes, symptoms, diagnosis and treatment of both types, as well as some tips on how to prevent and manage contact dermatitis
Irritant contact dermatitis is caused by direct damage to the outer layer of the skin by a substance that is either too harsh or used too frequently. Some examples of irritants are soaps, detergents, solvents, acids, alkalis, cement, powders, dust, soil and water. Irritant contact dermatitis can affect anyone, but some people are more prone to it, such as those with atopic eczema, dry skin, or occupations that involve wet work or exposure to chemicals.
The symptoms of irritant contact dermatitis usually appear within a few hours or days of contact with the irritant. They include:
- Redness, swelling and warmth of the skin
- Itching, burning and stinging sensations
- Dryness, cracking and peeling of the skin
- Blisters, ulcers and infections in severe cases
The symptoms can affect any part of the body, but are more common on the hands, face and areas that are rubbed by clothing or jewellery.
The diagnosis of irritant contact dermatitis is based on the history of exposure to the irritant, the appearance and distribution of the rash, and the exclusion of other possible causes. Sometimes, a skin biopsy may be needed to confirm the diagnosis.
The treatment of irritant contact dermatitis aims to reduce the inflammation, relieve the symptoms and prevent further damage to the skin. The main steps are:
- Avoiding or minimizing contact with the irritant
- Washing the affected area with lukewarm water and mild soap as soon as possible after exposure
- Applying moisturizers regularly to keep the skin hydrated and protected
- Using topical corticosteroids to reduce the inflammation and itching
- Taking oral antihistamines to ease the itching and swelling
- Using antibiotics to treat any secondary infections
- Seeking medical advice if the symptoms are severe, persistent or widespread
Allergic contact dermatitis is caused by an abnormal immune response to a substance that the body recognizes as foreign. This substance is called an allergen, and it can be anything from cosmetics, fragrances, metals, rubber, plants, medicines and more. Allergic contact dermatitis can only affect people who are sensitized to the allergen, meaning that they have been exposed to it before and developed an immune memory. The first exposure may not cause any symptoms, but subsequent exposures can trigger an allergic reaction.
The symptoms of allergic contact dermatitis usually appear within 48 hours of contact with the allergen, but sometimes they can be delayed for up to a week. They include:
- Redness, swelling and warmth of the skin
- Itching, burning and stinging sensations
- Dryness, scaling and flaking of the skin
- Blisters, oozing and crusting in severe cases
The symptoms can affect any part of the body, but are more common on the areas that are directly in contact with the allergen, such as the ears, neck, wrists, hands and feet.
The diagnosis of allergic contact dermatitis is based on the history of exposure to the allergen, the appearance and distribution of the rash, and the results of patch testing. Patch testing is a procedure that involves applying small amounts of various allergens to the skin and observing the reactions after 48 and 96 hours.
The treatment of allergic contact dermatitis aims to reduce the inflammation, relieve the symptoms and prevent further exposure to the allergen. The main steps are:
- Avoiding or minimizing contact with the allergen
- Washing the affected area with lukewarm water and mild soap as soon as possible after exposure
- Applying moisturizers regularly to keep the skin hydrated and protected
- Using topical corticosteroids to reduce the inflammation and itching
- Taking oral antihistamines to ease the itching and swelling
- Using antibiotics to treat any secondary infections
- Seeking medical advice if the symptoms are severe, persistent or widespread
Prevention and management of contact dermatitis
Contact dermatitis can be prevented and managed by following some general tips, such as:
- Reading the labels of products and avoiding those that contain potential irritants or allergens
- Wearing gloves, protective clothing and barrier creams when handling or working with irritants or allergens
- Washing the hands and body thoroughly after contact with irritants or allergens
- Changing and washing clothes and bedding regularly to remove any traces of irritants or allergens
- Using mild, fragrance-free and hypoallergenic products for personal care and cleaning
- Keeping the skin moisturized and healthy
- Avoiding scratching or rubbing the affected area
- Seeking medical help if the symptoms do not improve or worsen