Eczematous dermatitis: Eczema is defined as a form of non-infectious inflammatory skin disease characterized in acute stage by erythema, oedema, papules, closely set pin head vesicles which lead to oozing, and crusting. As the disease progresses, scaling and lichenification takes place and fissures appear. Intense itching produces excoriation. Secondary infection may take place. Both acute and chronic stages can be seen in the same patient at the same time.
On the other hand dermatitis means inflammation of the skin. Both eczema and dermatitis are synonymous. Eczematous dermatosis is widely prevalent all over the world constituting 15-20% of all dermatological problems. The causes of origin can be extrinsic or intrinsic or even mixed. Depending on the aetiology, eczema are divided into:
1. Exogenous
(a) Contact dermatitis
(b) Infantile eczema
(c) Photo allergic dermatitis
(d) Infective eczema
2. Endogenous
(a) Atopic dermatitis
(b) Seborrhoeic dermatitis
(c) Discoid or nummular eczema
(d) Neuro dermatitis
(e) Pompholyx
The extrinsic causes include allergic reactions to chemical agents, plant products (Pollens, leaves, fruits etc) mineral and physical agents while in intrinsic there is allergy to food articles (fish, eggs, milk),. toxins from the gastro intestinal tract.
Psychogenic factors may also play their role in the causation of disease.
Contact dermatitis
It is a form of dermatitis which is more common in industrial workers. The first eruption begins at the site of contact with thc offending agent (cosmetics, chemicals, plant and animal products). Sometimes several substances may be responsible. This form of dermatitis is good example of cell mediated immune disease of type IV reaction.
An unusual pattern of skin lesion (odd shaped erythema and scaling) should arouse suspicion. A careful history about the offending agent shall be helpful. This can be further confirmed by Patch testing where the suspicious substance in diluted form (1% aqueous solution) is applied to the back and left for 24-48 hours. Positive reaction is indicated by an area of eczema.
Treatment is to remove the person from irritant responsible for causing eczema. Topical steroid cream applied at the site of lesion shall be helpful.
Atopic dermatitis
It is also known as infantile eczema. It is widely prevalent and represents an inherited tendency which predisposes the child to suffer from atopic dermatitis, bronchial asthma etc.
A child has 30 per cent chances of developing it if one parent is effected and 60 percent if both parents are effected. Genetic susceptibility rather than simple Mendelian inheritance may be playing a role in its aetiology. Sufferers from the condition may have coexisting asthma or hay fever. There is often a long family history of allergic diathesis.
Immune functions are deranged in sufferers of the disease. There are higher levels of 1gB and defects in cell mediated immunity. The disturbances in lymphocytes involve T-cell helper cells which secrete different types of lymphokines with opposing functions. A balance is maintained between the two types of cells but in atopic dermatitis T helper-2 cells dominate, thus disturbing the balance.
Diet has also been blamed as one factor. Some food stuffs like eggs, milk, fish are known to worsen the eczema. Children may show positive prick test to many environmental allergens.
Clinical features
It is primarily a disease of infants and young children though in small percentage it may pass onto adult life. 60% of infants are affected in first year and by the age of 5 years, 90% of children are affected. Symmetrical patches of erythematous, papulo vesicular lesions with scaling are distributed on cheeks, scalp, neck, trunk and extensor surfaces of lower legs. In infants, on the face perioral and nasal areas escape while in children lesions appear on antecubital and popliteal fossa, neck, thigh and ankle. The lesions are extremely itching and oozing may take place. At any age the eruptions may become generalized. Lichenification may set in as papules coalesce to become plaques. The skin of patients of atopic dermatitis may become dry (Xeroderma). Palmar skin of such patients have often more lines and creases than normal (Hyperlinear palms) and this is an important diagnostic sign. Constant rubbing and scratching not only produces lichenification in long standing cases but also exaggerates skin surface markings.
Constant rubbing of the eyes produces thickening and hyper-pigmentation round about the eyes and makes skin fold prominent. This is called Denny Morgan Fold. Disease which has begun in infancy and early childhood clears in late childhood but may flare up in adult life. Cases of atopic dermatitis are liable to suffer from secondary bacterial or viral infections.
Diagnosis
Extensive itching with erythematous papulo vesicular lesions in an infant / child shall suggest the diagnosis IgE levels are markedly increased. Biopsy is non-specific.
Treatment
Patient should avoid using any substance which may irritate the lesion. These include swollen clothes, extremes of temperature, frequent washing and soaps.
