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Dermatitis And Eczema: Clinical Significance, Pathogenesis, Etiology And Causes
A General Overview
These are among the most common dermatological problems accounting for 25 to 30% of all dermatoses. The term “Dermatitis” and “eczema” are used synonymously by most of the dermatologists. In the diagnosis of this condition, three steps are involved.
- Establish the diagnosis as dermatitis and eczema;
- Determine the morphological type; and
- Identify the etiological factor.
The Greek term eczema means “boil out”. Dermatitis (eczema) is defined as a non-contagious inflammation of the skin characterized by erythema, scaling, edema, vesiculation and oozing. Eczema is caused by antigen antibody reaction. The epidermis shows superficial edema and vesicle formation. Eczema may be acute, subacute or chronic.
Pathogenesis: Acute eczema may develop through different stages. It starts as itchy erythema and proceeds through population with edema, vesiculation, weeping and crusting, postulation and scaling to lichenification. The lesions may also heal without leaving scars. These stages are seen in most of the typical eczemas. The acute stage passes off within two weeks either to go into the subacute and chronic stage or to heal. Subacute stage is characterized by papules and scaling with moderate edema and erythema. Chronicity develops if the cause persists and it may last for months to years. In chronic eczema, the skin becomes thickened and pigmented with prominent criss-cross marking- termed lichenification- which is the end result of all chronic eczemas. Histologically, the lesion shows intercellular edema (spongiosis) and vesiculation. Mild to moderate inflammatory changes may be seen. Chronic cases are characterized by hyperkeratosis, acanthosis and lymphocytic infiltration of the upper dermis.
Etiology And Causes
The two requisites for the development of eczema are: an allergic or sensitive skin and presence of an allergen or irritant.
Predisposing causes: The main predisposing causes are:
- Familial predisposition
- Climatic and other environmental factors,
- Psychological factors, and
- General physical debility.
Atopic tendency may be inherited. Bronchial asthma and eczema may be seen in the same individual and in families. These may show a see-saw relationship. Apart from the general cause, local factors which lower the resistance of the part such as dryness of skin (xeroderma), ichthyosis, greasy skin, hyperhydrosis, varicose veins, prolonged dependency, and chill- blains favour the onset of eczema.
Precipitating Causes: These may be several, including chemicals, plants, synthetic clothes, cosmetics, jewelries, drugs, systemic and local infections, dietary articles and focal sepsis. Once the skin is irritated and sensitized, this becomes easily susceptible to further insults. Scratching, application of irritant chemicals, exposure to climatic variations and emotional stress tend to perpetuate the process. Other areas may also become sensitized (autosensitisation) and the lesions becomes disseminated. The term “status eczematicus” is applied to the condition when the skin becomes so sensitive that it reacts adversely to all local medications.
© 2014 Funom Theophilus Makama