Eczematous Dermatoses

I have suffered from eczema all my life, less so than when I was a child when it was quite persistent and a real nuisance. Now and again it flares up, but usually stays at low and very moderate levels. Here is an explanation of the condition which I recognise and I have summarised (and added to slightly with experience) from the source.

Inflammation has the character of epidermal cells separated by oedema fluid (spongiosis) and, in the upper dermis beneath the epidermis, an accumulation of inflammatory cells vasodilation. Eczematous disorders can have endogenous (internal) causes or external environmental causes. Inflammation comes from toxic chemicals (e.g, soap powders, plants), mechanical trauma (reactions to stressful events) and immunological reactions.

Atopic Dermatitis

This mainly affects younger people and is very itchy from 2 months and over. It has an unknown cause. There are secondary effects from scratching with a persistent pruritus. Itchiness intensifies with temperature changes, rough clothing (as with wool), and other environmental influences including mental reactions to events.

Scratching and rubbing the skin causes thickening and produces markings (lichenification). Although scaling is seen as part of this process, it in fact happens as part of the eczematous process.

The palms show more skin markings with some pinkness. The cause of this is unknown. The cheeks may be whiter and the eyes show more crease lines probably from rubbing. For this reason nails become smoothed. Eyebrows and eyelashes may be deficient. Black skin may have a follicular component and there are wide contrasts of pigment.

Rubbing with a blunt object produces a white mark (white dermographism)

There is no single genetic defect but 30% of patients have one affected parent. It is getting more common with 6% of infants, 2% in the community but 15% of those who seek medical treatment. 75% of patients effectively lose the condition by 15 years old though atopic dermatitis can become palmar dermatitis later. While anyone has the condition, it is subject to recurrent flares. 30% of atopic dermatitis patients have asthma and they are more likely to have hayfever. These cluster within families. There is no set, predictable or proportionate way these relate to each other. They share aberrant pathogenetic mechanisms affecting immunity. Unsaturated fatty acids are reduced in infants. Sufferers are likely to have chronic uticaria (allergic hypersensitivity with histamine release from mast cells in the skin) and this relates to swelling after cold weather, lesions following pressure, swelling with marked skin, reaction to sunburn (solar uticaria) and to nettles and certain drugs. Whilst antihistamines are most useful in these cases, their effects last only a few hours. Older versions may cause hypnotic side effects.

Other related conditions are migraine and alopecia (hair loss).

There are complications like pustules in impetiginized areas, cellulitis (inflammation) and viral warts. Sufferers can become seriously unwell with human herpes although this passes after 10 to 14 days.

Protection and Assistance

It is a good idea to protect the skin from irritants that lead to flares in the condition. Also protect the skin from further injury. Infection is always a further problem.

Bland greasy emollients can be more effective than many creams. They prevent water evaporation which has these benefits: they make the skin look and feel smoother, the skin cracks less, there is a decreased tendency to scaling, itching decreases. There are some anti-inflammatory properties.

Corticosteroids (hydrocortisone, clobetasone, 17-butyrate, flurandrelone) do not cure but only suppress. They need to be given over long periods and have side effects. Pituitary adrenal axis suppression can be life threatening. Corticosteroids thin the skin. They mask infection (e.g. ringworm). Sudden withdrawal leads to a flaring of the eczema. There is also acquired tolerance (tachyphylaxis). These points are why the least potent cream possible is given with shifts in treatment to get around the building tolerance.

Tar ointments (like Clinitar) are little understood in how they work but are used for chronic lichenified (thickened and marked) areas.

In some cases Photochemotherapy may improve the skin but using UVA light does risk cancer.

Marks, R. (1993), Roxburgh's Common Skin Diseases, 16th edition (first edition, 1932), London: Chapman and Hall Medical, pp. 100-110. ISBN 041241130X