Dermatitis

Dermatitis ( Eczema )

By
Hala Al- Salman

Discoid ( nummular ) eczema

It's a common type of endogenous eczema, mainly affect the limbs of middle-aged male. Characterized by single or more commonly multiple, coin-shape, vesicular or crusted, highly itchy plaques, usually less than 5 cm.
It has chronic course with exacerbation and remission. It tend to persist for many months and the recurrences often appear at the same site of previous plaques.

Cause:

Unknown, but chronic stress is often present.
A reaction to bacterial antigen has been suspected, as the lesions show staphylococci on culture and the response to steroid-antibiotic preparation better than either separately.

Treatment:

Topical potent steroid with antibiotics.

Pompholyx:

It's an acute or subacute vesicular eruption, in which recurrent bouts of very pruritic vesicles or large blisters appear on the palm, fingers and/or the sole lasting few weeks to be recurred at irregular intervals. Usually affect young adults and rarely children and aged.

Cause:

Unknown, but sometimes provoked by heat, focal infection or emotional upsets.
The vesicles are not plugged sweat ducts so the term " dyshidrotic eczema " better avoided.


Differential diagnoses:
Id reaction to tinea pedis.
Pustular psoriasis.
Acute contact dermatitis.

Treatment:

As for acute eczema.
Antibiotics.
Aluminium acetate or potassium permanganate soaks.
Very potent topical steroid cream.

Complications:

Secondary bacterial infections.
Lymphangitis.

Pityriasis alba:

It's a common condition, more usual in atopic individuals. Usually appears before puberty, affect mainly the face, neck and the arms.
The lesions begin as a non-specific erythema and gradually become hypopigmented patches with fine scaling and ill defined edge. It improve after puberty.

Treatment:

Emollients.
Mild topical steroids.


Localized neurodermatitis: (Lichen simplex chronicus)
It's an eczematous eruption created by repeated rubbing or scratching of a single localized area, as a habit or in response to stress, but there is no underlying skin disorder.
The patient presented with a single, fixed itchy, lichenified plaque.
Site: area accessible or easily reached by the hands, including the nape of the neck in female, the legs in male, and the ano-genital area in both sexes.

Treatment:

Explanation: the patient should know that the rash will not clear until scratching or rubbing is stopped.
Potent topical steroid or occlusive bandaging to break the scratch-itch cycle.
Intralesional steroid injection in resistant cases.

Gravitational (stasis) eczema:

Chronic patchy eczematous condition of the lower legs sometimes accompanied by varicose veins, edema and haemosiderin deposition. It may become severe and spread to the other leg or even become generalized.

Cause:

It's often accompanied by obvious venous insufficiency that cause partial devitalization of the skin which predispose it to many complications like contact dermatitis and ulceration.

Treatment:

Elimination of edema by elevation, pressure bandages or diuretics.
Topical steroid of moderate potency, and avoid potent steroids.

Asteatotic eczema:

It's a common itchy eczema, usually affect the legs of elderly patients. It produce a network of fine red superficial reticulated cracks on a background of dry skin.


Cause:
It affects elderly whose skin is dry with a tendency to chap. Other contributing factors include the removal of surface lipid by over-washing, low humidity of winter, central heating and the use of diuretics and hypothyroidism.
Very severe cases may be part of malabsorption syndromes, zinc deficiency or internal malignancy.

Treatment:

The use of mild or moderately potent steroid in a greasy base.
Bath should be restricted.
Daily use of unmedicated emollients usually prevent recurrences.

Juvenile plantar dermatosis:

It affects the skin of the weight-bearing area of the feet, particularly the forefeet and undersides of the toes. The skin becomes dry and shiny with deep painful fissures. The toe webs are spared. It affect children between 3-15 years and even if not treated the condition clears in early teens.

Cause:

The condition is thought to be related to the impermeability of the modern socks and shoe linings with subsequent sweat gland blockage and it's called " Toxic sock syndrome "
Some consider the condition as a manifestation of atopy.
Treatment:
the use of cotton socks.
emollients as emulsifying ointment, icthamol, lactic acid.
topical steroid.

Napkin ( Diaper ) Dermatitis:

The most common eruption in the napkin area is irritant in origin, and is aggravated by the use of water-proof plastic pant.


Cause:
The mixture of faecal enzymes and ammonia produced by urea-splitting bacteria when it allowed to remain in prolonged contact with skin, it will lead to a severe reaction.
The overgrowth of yeast (Candida albicans) is another aggravating factor.

Clinically:

There is moist, glazed and sore erythema affecting the napkin area in general with the exception of the skin folds, which tend to be spared.
Secondary infection with candida will produce small erythematous papules or vesico-pustules at the periphery of the main eruption ( Satellite lesion ).

Differential diagnoses:

Candidal infection.
Seborrhoeic dermatitis.
In both conditions there is involvement of the skin folds.

Treatment:

The area should be kept clean and dry (which is difficult).
the child should be allowed to be free of napkin as much as possible.
The use of super-absorbent diaper if preferred.
The napkin should changed regularly especially at night.
The area should be cleaned at each nappy change with aqeous cream and water.
The use of protective ointment: zinc, caster oil or silicon.
Potent steroid should be avoided, but mild one ( hydrocortisone) with antifungal and antiseptic preparation are useful.










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