Babies can have it on the cheeks

and upper chest and in the nappy areas and get better from age 4 . In children the most commonly areas affected are front of the elbows , behind the knees , back of the wrists and outer parts of the lower legs.In older children constant scratching causes the skin to thicken in some areas .The incidence is increasing and now affects about 25% of the population

In normal skin, cells of the bottom layer of the skin (epidermis ) multiply and gradually move up over a period of 20 days and are shed from the surface . In eczema and psoriasis this process is speeded up and can take as little as five days . An irritant antigen - IgE mediated eg food stimulates these cells to multiply .

Faster turnover means that the bonds between the cells are weak , so water and oil are lost from the skin surface and it becomes dry and cracked . Blood vessels come near the surface giving it a red appearance .The aim is to restore this water with moisturizers like aqueous cream and protect it with oils which form a waterproof film and stop drying .

A bath oil like Balaneum is useful and since bacteria can worsen it , something with antibacterial action like Oilatum plus can be beneficial . Emollients should be applied three or more times a day in a direction along which the hair lies and not against it and vary in the amount of water , very dry skin needs soft white paraffin - the most greasy and least water containing , and then as improvement occurs less greasy ones like Diprobase , Ceraban , E45 or least ones like aqueous cream can be used . A teaspoonful covers a leg . Instead of soap wash E45 cab be substitured.

If redness and itching are the biggest problem then short term steroids for five days can be used - the most potent is oral prednisolone 20mg daily for five days for severe generalized eczema , next is dermovate cream , then less potent is eumovate , elcon -gp 2 needs to be applied only once a day , and least which may not cause thinning at all is hydrocortisone 1% -gp 4ceam which can be used for short term on the face . Steroid creams thin the skin and so use should be limited for bursts for a few days 7 or so and then allow two weeks for the skin to recover .. They are applied in finger tip units , 2ftus = 1gram . Discoid or nummular eczema also needs steroids .

Often these lesions are infected with Staph and Strep and need flucloxacillion or erythromycin orally . Fucibet cream is a useful antibiotic/steroid combination.Loose cotton clothes are better than woollen ones which might scratch the skin. Very thick skin due to scratching - may need tar oils .

Newer treatments not yet available like tacrolimus and ascomycin on the skin modulate the immune response and improve eczema in 80% of patients . Primrose oil is ineffective . Herbal ones have not undergone clinical safety and efficacy tests and are not advised . Boots cold cream was reported in some papers as a cure for baldness. Most cases of eczema are due to unknown causes . Rast test can tell us those which might have a cause . If positive then a 3 month trial o f anti mite measures like special mattresses , daily vauuming , chemical sprays can help .

Contact dermatitis

is a form of eczema in which some chemicals eg hair dyes , nail varnish ( and spreads to eyes on touching but leaves the thick nail unaffected) , nickel in zips or jewellery, poison ivy , latex , chrome in cement can cause skin irritation , redness and swelling and cotton lined gloves may need to be worn. Almost any compound can cause contact dermatitis and patch testing using strips is useful . Steroid creams are very useful . Soon the genes which may cause will be identified and blocked. Putting the pillow and bed sheets in a freezer for an hour a week can kill off mites .