Eczema is a general term used for non-contagious skin-related symptoms like itching, redness, scaling, crusting and blistering) that occur in various types of skin inflammation (dermatitis). It is also used interchangeably with the term atopic dermatitis, which is an inflammatory skin disease seen with immune hypersensitivity and often starts in early childhood.
Eczema arises from damage to the outermost layer of the skin called the epidermis. It is categorized into various types based on the specific causes and symptoms. Eczema either resolves by itself or keeps recurring throughout life. Many sufferers are also susceptible to allergic conditions like asthma and rhinitis. Collectively these conditions are referred to as the allergic triad.
The appearance of eczema varies among patients and depends on the cause or type of dermatitis. The commonly affected areas include the skin of face, scalp, neck, elbows, knees and ankles.
Some of the common symptoms of eczema are as follows:
- Dry and reddish skin that causes intense itching (pruritis) or burning sensation.
- Thickening, crusting (lichenification) and scaling of skin due to continuous scratching.
- Blisters that ooze.
- Continuous scratching of the affected areas may lead to skin wounds that subsequently get infected with bacteria.
The causes of eczema vary according to the type of dermatitis and include allergies, autoimmune diseases and inflammation due to skin irritants. Since some forms of eczema seem to run in families, there might be genetic factors that predispose certain people to eczema. Some forms of eczema may arise with other diseases, especially systemic conditions that affect many organs of the body simultaneously. However, the cause of some types of eczema remain unknown (idiopathic).
The following are some of the common types of eczema and their causes:
- Atopic dermatitis is caused by strong allergic immune response to environmental allergens (certain foods, cosmetics, dust mites, molds and dander). Defect in filaggrin protein, which maintains the barrier functions of the epithelium, is also thought to be a causative factor.
- Contact dermatitis is caused by skin contact with either an allergen (allergic contact dermatitis) or an irritant (irritant contact dermatitis). Common allergens or irritants include chemicals, soaps, latex, cosmetics, certain plants, and body fluids.
- Exfoliative dermatitis is associated with pre-existing skin disorders, cancers and the use of certain drugs like penicillin, sulfonamides, and barbiturates.
- Lichen simplex chronicus (neurodermatitis) is caused by repetitive scratching/rubbing of the skin in response to a real or perceived itch.
- Nummular dermatitis is characterized by coin or disc-shaped itchy skin lesions. It is often associated with dry skin in winters and affects middle-aged persons. The causative factor is not known.
- Seborrheic dermatitis is caused by inflammation of the sebaceous glands of the skin. The fungus Pityrosporum ovale has been implicated in its causation.
- Stasis dermatitis is caused by pooling of blood in the veins of the lower legs, resulting in leaking of fibrin protein and inflammation of the skin.
Treatment of eczema is aimed at managing the symptoms initially and isolating the cause and treating it accordingly.
- Corticosteroid creams on the skin reduces the inflammation.
- Oral anti-histamines are given in case of severe and widespread itching.
- Oral immunosuppressants (methotrexate, cyclosporine) are prescribed when conventional medicines are ineffective.
- Phototherapy with UV light is another option in some cases of eczema.
- Antibiotics are used when the skin lesions become infected with bacteria.