Atopic Dermatitis

Atopic dermatitis (“milk crust”) is one of the most common skin conditions among infants and children. In Europe and North America, it affects around 2.5 – 5 % of the population. The risk of contracting atopic dermatitis is 30 % where one parent is already a sufferer, and 60 % where both parents are sufferers. A congentital predisposition is found in about two-thirds of atopic dermatitis patients. The initial symptoms appear in 80 % of patients by the time they reach the age of two. It is less common for the illness only to appear in adulthood.
Atopic dermatitis is a skin condition with clustering in families. It frequently reacts pathologically to environmental factors. Patients with atopic dermatitis tend to suffer from allergic rhinoconjunctivitis (allergic cold and allergic conjunctivitis) and allergic asthma. This family predisposition is the expression of an atopic reactivity, which is believed to be based on polygenic factors. Polygenic means that a number of different genes are involved in triggering the disease.
Atopic dermatitis is an inflammatory skin disease that is accompanied by strong itching and is usually chronic. Some patients suffer acute attacks at considerable intervals. The most important symptoms are an extremely dry skin, intolerable itching, and eczema caused by scratching. Discrete indications of atopic dermatitis are the characteristic loss of the outer parts of the eyebrows, sometimes marked folds in the middle of the lower eyelid, and not infrequently also poorly healing cracks at the corners of the mouth and where the earlobes join the head. Reddened patches with unclearly defined margins occur either intermittently or chronically over a long period of time. Papules and plaques, i.e. areas of raised, red, swollen-looking skin occur. In nearly all cases, marks of scratching can be seen. After a long period, the skin coarsens and thickens, with clearly visible lichenification caused by constant rubbing and scratching. The horny layer on the palms of the hands and soles of the feet becomes thicker, and painful cracks, so-called fissures, develop. Chronic inflammation and constant rubbing result in increased pigmentation of the skin, especially in the area of the neck, giving rise to the “dirty neck” phenomenon.

Accompanying eczema, i.e. inflammatory skin changes, frequently occurs in the insides of the elbows and knees. Other regions that are frequently affected are the scalp, the eyelids, the forehead, the sides of the face, the wrists, the tops of the feet and the hands. Patients with severe atopic dermatitis may even temporarily develop inflammatory changes of the whole skin.
A typical symptom of atopic dermatitis is white dermographism, i.e. sustained paling of the skin after scratching or stroking with a hard object. Patients without an atopic predisposition normally respond to skin irritations of this kind with red marks or weals. In many cases, the symptoms improve spontaneously or even disappear altogether with increasing age. The skin changes may be reversed altogether in about half the patients by the time they reach the age of 20. However, as the genetic predisposition is still there, a new attack may occur at any time given the appropriate provocation factors. 30 – 50 % of patients also develop a further atopic illness such as hay fever or asthma.

Provocation factors are drying of the skin through frequent bathing and washing. Especially in childhood, 15 – 20 % of patients suffer from inhalation allergies to pollen, animal hairs and house dust mites, and in rarer cases to certain foodstuffs.

In adulthood, these allergic reactions only seldom act as triggers for a new attack. In this age group, emotional stress is a relatively frequent provocation factor. Infections of the skin, for example with staphylococcus aureus or group A streptococci bacteria can frequently cause the skin condition to deteriorate. Fungal and viral infections may also occur. In people with an inflammatory skin condition, for example, herpes simplex can spread over the whole body, a condition known as eczema herpeticatum. Itching irritation is intensified by contact between wool and skin. A typical feature of this is the acute itching that occurs when dressing or undressing through contact with and manipulation of the skin. Itching results in scratching, which aggravates the inflammatory skin changes, and this in turn causes further itching.

Atopic dermatitis is worsened by emotional or mental stress. This should be avoided or at least reduced as far as possible by a conscious lifestyle. Relaxation exercises such as autogenic training, progressive muscle relaxation, meditation exercises, and thai chi or yoga can be helpful.

Atopic dermatitis should also be taken into account when choosing a career or job. Occupational factors such as working in damp/wet or dusty conditions or heavy sweating can markedly aggravate the condition.

Medication therapy for atopic dermatitis depends on the condition of the skin at any particular time. A difference must be made between acute states, with severe inflammation and weeping of the skin, severe itching and many scratch marks, from sub-acute and chronic states. The latter are characterised by lichenification (thickening of the skin), painful fissuring – especially on the palms of the hands, the fingers and the soles of the feet – and severe scaling.

During acute attacks, compresses soaked in black tea have a soothing and anti-inflammatory effect. Low-fat cortisone creams or milky cortisone mixtures can shorten the acute phase. As the plaques also tend to be colonised by staphylococci and other bacteria which worsen the illness, mixtures containing antibiotics may also be given. The itching can be reduced by antihistamines. However, these should not be applied in the form of creams or gels, as they frequently produce allergic reactions, but in the form of antihistamine tablets, juice or drops. Where the eczema is more severely infected by bacteria, systematic antibiotics are necessary if local disinfectants do not produce a sufficient response.

In the case of subacute and chronic skin changes, consistent creaming of the skin is crucial. Oil baths, oil-in-water emulsions or even water-in-oil emulsions with moisture retention factors such as urea, glycerine or lactic acid can be used for this purpose. More severe itching responds to menthol and camphor preparation or polidocanol in the care creams. Tolerance of these creams often varies strongly depending on the skin condition, so they must be matched individually by a dermatologist. Depending on the acuteness of the condition, ointments containing cortisone or with other active substances such as tar, shale oil, extract of oak bark, zinc, liver oil or bufexamac may be used.

In most cases, light therapy (phototherapy) with UVA and/or UVB radiation has a positive effect. This is due to the immuno-suppressive effect of the UV radiation. UVA 1 light is especially effective in the case of acute atopic dermatitis, selective UV therapy (SUP) in the case of chronic skin changes.

Also a change of climate can favourably affect atopic dermatitis. Both mountain climate (absence of allergens, climate stimulation) and sea air, e.g. on the islands off the German North Sea coast, can be recommended. Many atopic dermatitis sufferers also find that the moderate climate of the Canary Islands does them good. However, climate therapy of this kind usually only produces a stabilisation of the condition if the stay is at least 3 weeks.

The most severe cases of atopic dermatitis have to be treated systematically, at least for a time, with cortisone or other drugs that weaken the immune system, such as cyclosporin A. Also in the process of development are creams and ointments containing substances that regulate the immune system.

The basis of any treatment must be to avoid or at least reduce the influence of the factors that provoke atopic dermatitis. One of the unspecific factors that can cause an attack of itching is dryness of the skin. This is worse especially in winter because of the very low level of humidity in heated rooms with tightly fitting windows. On the other hand, though, also a heat build-up in hot, humid temperatures in summer can lead to increased itching and inflammation of the skin. Irritation of the skin by wearing clothes with a rough surface should be avoided. Climatic influences can to some extent be offset by the choice of clothing. Wool should always be avoided. In hot weather, loose clothing made of cotton should be worn, and in cooler temperatures also items such as coats, pullovers, scarves and gloves that are made of fleece material can be worn. The skin must be regularly tended with water-in-oil preparations or, depending on skin condition and the surrounding temperatures, oil-in-water emulsions. This can be supplemented by oil baths and oil showers.

The best method for using care products is to apply them frequently but thinly. Besides soiling the clothes, applying creams and ointments too thickly can also produce a “greenhouse effect”, with heat build-up, itching and reddening of the skin.

In the case of patients with atopic dermatitis, type I allergens (on the skin) can trigger a direct allergic reaction. This is particularly the case in areas of the body with increased sweat secretion and a thin horny layer. The triggering factor are allergens that reach the skin through the air (aeroallergens) such as household dust, mites, animal hairs or pollen. Food allergens can also cause the condition to worsen. In the case of patients with known sensitivity to dust mites, their concentration should be reduced indoors by removing, as far as possible, fitted carpets, upholstered furniture and textiles. Mite-proof covers for mattresses, duvets and pillows are also recommended. Atopic dermatitis sufferers should also use special vacuum cleaners with mite-tight filters. In the bedroom, the temperature should not exceed 15° to 16 ° C as mites reproduce more quickly at higher temperatures.

As animal hairs are among the most common allergens and frequently cause very severe reactions on the skin and mucous membranes, atopic dermatitis sufferers are advised not to keep any animals at all and not to pursue sports such as riding which involve contact with animals.

Food allergens can – though rarely – trigger atopic dermatitis attacks. However, there is no generally recommended diet for people with the condition. These allergens have to be individually tested, though even if allergic reactions are found in a prick test or through blood analysis, this is no proof that the allergen also triggers attacks of atopic dermatitis. Testing must always be followed by a non-use period with subsequent provocation. Altogether, food allergies in patients with atopic dermatitis are much rarer than generally assumed. If an allergy is shown to exist through testing and a provocation trial, the foodstuff concerned should naturally be avoided. It is, however, quite possible that a few years later the foodstuff will be tolerated well again. A preventive diet against atopic dermatitis in childhood should, if anything, be rejected, as through this avoidance of certain substances the body is prevented from becoming gradually accustomised to the foodstuff concerned