By Dr Ananya Mandal, MD
Dermatitis is a common skin condition caused by inflammation of the skin. There are several different forms of dermatitis but all are caused by the skin reacting to allergens or irritants. Dermatitis is usually characterized by red, itchy skin that can become blistered and weepy.
There are various causes of dermatitis and the cause determines which type of dermatitis a person is diagnosed with. The different types of dermatitis and their causes include:
Contact dermatitis describes a skin reaction that occurs when the skin makes contact with either an allergen or an irritant. An irritant physically damages the skin while an allergen triggers an immune response that leads to a skin reaction. Common known causes of irritant contact dermatitis include detergents, soaps, disinfectants, metals such as nickel, cement, fragrances or perfumes, cosmetics, and some plants such as mustard, clematis.
Examples of the substances that may trigger allergic contact dermatitis include metals such as nickel or cobalt, rubber, strong adhesives, some dyes and resins in clothes, and some topical medicines such as corticosteroid creams.
Otherwise known as eczema, this form of dermatitis occurs when the body is hypersensitive to certain foods, allergens or environmental factors. The condition often runs in families and may occur alongside other atopic conditions such as hay fever and asthma. Food allergies can make eczema worse and examples of food items thought to cause more severe eczema symptoms in children include cow's milk, wheat, soya, nuts, fish and eggs.
This condition is caused by nerve endings underneath the skin that have become irritated, causing an intensely itchy sensation and an overwhelming urge to repeatedly scratch. This scratching can eventually lead to thickening and redness of the skin.
Stasis dermatitis occurs when varicose veins interrupt the venous flow from the legs back to the heart, causing blood to pool in the lower limbs. Blood and fluid then leak from the veins into the skin tissue.
This condition affects skin areas with sebaceous glands and typically occurs across the face, nose, and inside of the ears. Other skin areas affected include the back, neck and chest. When the condition affects children, it is often termed "cradle cap".
The cause of seborrheic dermatitis is unknown but factors implicated include a yeast called Malassezia that is present in the skin's oily secretions, neurological conditions such as Parkinson's, stress and fatigue.
This is a condition that mainly affects women and refers to the development of a rash around the mouth formed of tiny raised, red bumps. The condition has been associated with the use of topical steroids, moisturizers, cosmetics and sunscreen.
This form of dermatitis is a symptom of the gut condition celiac disease, caused by an allergy to a substance called gluten which is found in wheat, rye and other grains.
Reviewed by Sally Robertson, BSc