What is eczema?

Eczema is a type of dermatitis (inflammation of dermis or the skin). Eczema can present with different clinical presentations in different individuals, but the histological finding of eczema is common for all, which is intercellular edema of the epidermis known as spongiosis. Eczema is the final common expression for a number of skin disorders. Primary lesions of eczema may include macules (a discolored spot on the skin that is not raised above surface) which are erythematous, papules (small elevations in the skin) and vesicles, which can coalesce to form patches and plaques on the skin. Secondary lesions seen in severe eczema from infection are marked by weeping and crusting.

What are the Synonyms of eczema?

Atopic dermatitis and atopic eczema are synonyms of eczema.

What is the etiology (cause) of eczema?

The etiology of eczema is only partly explainable with clear genetic linkage to its causation. The genetic cause is clear from the fact that when both parents are affected by eczema, the disease (eczema) manifest in more than 80% of the children and when only one parent is affected by eczema, the prevalence of eczema in children is approximately 50%. Patients with eczema or atopic dermatitis have a variety of immunological abnormalities like increased IgE (immunoglobulin E) synthesis (so increased serum IgE), and impaired delayed-type hypersensitivity reactions.

What are the clinical manifestations of eczema?

The important clinical symptoms of eczema are typical eczematous dermatitis lesions, itching and scratching, exacerbations and remissions of symptoms (this is marked and important clinical finding), symptoms generally lasts more than 6 weeks, lichenification of skin, personal or family history of asthma, allergic rhinitis, food allergies, or eczema etc.

The clinical manifestations can vary according to the age at presentation. 50% of eczema manifestations generally present before the age of one year and by age of 5 years more than 80% of the cases of eczema occur. The infantile manifestation are characterized by weeping inflammatory patches and crusted plaques on the face, neck, and extensor surfaces and childhood and adolescent pattern is marked by dermatitis of flexural skin, especially in the antecubital (inner side of elbow) and popliteal (back of the knee) fossae. Eczema or atopic dermatitis generally resolves spontaneously in approximately half of the individuals, but the remaining will have dermatitis in their adult life and approximately 80% of them will have allergic rhinitis or asthma. The manifestations of lesions may be similar to those seen in childhood, but adults may have localized disease like hand eczema. In individuals with localized lesions, eczema should be suspected if there is a typical history, family history, increased palmar skin markings, an increased incidence of skin infections, especially with Staphylococcus aureus or Dennie's line (which is an extra fold of skin beneath the lower eyelid). In all age group an important clinical manifestation of eczema or atopic dermatitis is itching, which may be intense.

How eczema is treated?

Treatment of eczema or atopic dermatitis requires the understanding of the disease by the patient and also follows certain measures as part of management like bathing not more than once a day (use cool or warm water and only mild bath soaps), avoiding irritants etc. Immediately after bathing (while the skin is still moist) a topical anti-inflammatory agent should be applied to the areas of dermatitis and in the remaining parts of the skin, a moisturizer should be used to lubricate the skin (approximately 30 gram of moisturizer is generally required to lubricate the whole body every day for an average adult). General measures like adequate moisturizing with the application of moisturizers, judicious use of topical anti-inflammatory agents etc. as well as prompt treatment of secondary infection need to be taken.

Secondary infection of eczematous skin is common and need to treat promptly with appropriate antibiotics to prevent exacerbation eczema. Staphylococcus aureus is the common pathogen and crusted and weeping skin eczematous lesions are generally affected. If secondary infection with Staphylococcus aureus is suspected the eczematous lesions should be cultured and antibiotic sensitivity done and patients treated with systemic antibiotics active against S. aureus, while waiting for sensitivity results. Penicillinase-resistant penicillins or cephalosporins like dicloxacillin or cephalexin (250 mg 4 times a day for 7–10 days) are preferred and generally adequate. If the antibiotic sensitivity test shows different result, the antibiotic should be changed according to sensitivity test. As approximate 50% of the Staphylococcus aureus are MRSA (methacillin resistant Staphylococcus aureus) the drugs preferred these days are trimethoprim/sulfamethoxazole combination (1–2 double strength 2 times a day), minocycline (100 mg 2 times a day), doxycycline (100 mg 2 times a day), or clindamycin (300–450 mg 4 times a day). Any of the above antibiotics should be given for at least 7-10 days.

The itching of eczema should be controlled and generally first generation antihistaminics are used as they are mildly sedative (most likely mild sedation is useful in controlling itching as non sedating antihistaminics are not useful in treatment of itching in eczema). But sedation may be a problem for use of sedating antihistaminics and they should be used during bedtime, which can improve sleep.

Role of glucocorticoids (steroids) in treatment of eczema:

Low or medium potency glucocorticoids (steroids) are generally used in most of the treatment regimens of eczema or atopic dermatitis. Systemic absorption of glucocorticoids and atrophy of skin are the major concerns of glucocorticoids use and should be careful about, which are more common with more potent glucocorticoids and should be avoided. Low-potency topical glucocorticoids or non-glucocorticoid anti-inflammatory agents (NSAIDs) should be used in face to minimize skin atrophy. Tacrolimus ointment and pimecrolimus cream are the two non-glucocorticoid anti-inflammatory agents that are available now and approved by US FDA for topical use in treatment of eczema or atopic dermatitis. These two agents are reported not to cause skin atrophy or suppress the hypothalamic-pituitary-adrenal axis, as is seen in glucocorticoid use. But recently there are concerns about the role of these 2 agents (pimecrolimus and tacrolimus) in causing lymphomas. At present they are also more costly than topical glucocorticoids and they should be used with caution.

Systemic glucocorticoids should only be used in severe cases (severe exacerbations) which are not responding to topical glucocorticoids. If systemic glucocorticoids are used in patients with chronic eczema/atopic dermatitis the result is very good, but only temporary; when systemic glucocorticoids are withdrawn, invariably eczema/atopic dermatitis returns, sometimes with more severe form of dermatitis.

Immuno-therapy in eczema or atopic dermatitis is not useful. The role of dietary allergen is also controversial and they do not have any role beyond infancy. If individuals are not responding to conventional treatment, allergic contact dermatitis should be ruled out by patch testing.