A child with atopic eczema is more likely to go on to develop other atopic conditions such as asthma and allergic rhinitis (the so-called ‘atopic march’). Eczema is diagnosed in about 20 per cent of children during their first year of life and most children who are affected will have developed symptoms by the age of four. However, 60-70 per cent of children with eczema will experience remission by the age of 15. Relapses may occur later in life, affecting approximately 2 per cent of adults.
Eczema is diagnosed based on guidelines which are centred on the presenting clinical symptoms and patient history. A clue to the diagnosis of eczema is the presence of itch – if it doesn’t itch, it is unlikely to be eczema.
The sites affected and the presentation of eczema varies as the patient ages. With infants, the skin shows signs of widespread xerosis (dryness) and the first sites affected are normally the cheeks, chin and forehead. For younger school children, the distribution of eczema changes to affect the flexor surfaces of the elbows and knees, the antecubital and popliteal fossae respectively. These sites will show signs of erythema and are often lichenified (ie the skin has thickened) due to constant scratching.
As children progress into adolescence, the condition can spread to the eyelids, ear lobes, scalp and neck. Although eczema can clear in many teenagers, the skin remains susceptible to eczema and they can often experience flares as they develop into young adults. Eczema can persist into adulthood and will often continue to affect areas such as the antecubital fossa, the eyelids and hands. Adults with eczema tend to have skin that is drier and more lichenified than children. The course of eczema in those affected normally follows a relapsing and remitting pattern, which can last a lifetime.
The precise cause of eczema remains unclear, although there are several possible factors responsible and it is likely to be caused by a complex interaction between genetic and various environmental factors. The term eczema originates from the Greek word ‘ekzein’ which means to ‘boil out’, and this is an apt description for the typical presentation of an acute attack. The skin becomes intensely pruritic and patients scratch their skin, resulting in visible excoriations. In the more chronic stages, the skin undergoes lichenification, which is a response to repeated scratching.
The itch associated with eczema is the most debilitating symptom and can have a profound impact upon the sufferer or their carer. Itch can lead to sleep disturbance and loss of self-esteem as sufferers worry about their appearance. Constant itching results in scratching of the skin, which causes further itching, resulting in a vicious scratch-itch cycle.
Eczema treatment depends on its severity. NICE produced guidance on the management of atopic eczema in 2007, the key aspect of which is the use of emollients on a regular basis (irrespective of severity).
Emollients work to ‘waterproof’ the skin. That is, they form an impervious oily barrier that prevents loss of water from the surface of the skin and entry of allergens or irritants. Emollients are available as leave-on products such as creams, ointments, lotions and sprays, as well as wash products, which are designed to be used as soap substitutes.
Some practical tips on emollient use are shown in the panel overleaf. All patients should practise ‘complete emollient therapy’, which involves the use of a soap substitute, a wash product for the bath or shower, and application of a moisturiser throughout the day.
As emollients are effectively ‘worn’ by patients, in much the same way as an aftershave or perfume, the best emollient is the one that the patient is happy to use. Greasier preparations, although more occlusive, are likely to be problematic for office-based workers who spend time dealing with paper and computers, but are less of a problem for those who work outdoors. Most patients are happier using products that contain less oil and are easily absorbed without leaving a greasy film on the skin. Unfortunately, such lighter products need to be applied more frequently.
Topical corticosteroids are normally reserved for the management of an eczema flare. They work by suppressing the production of inflammatory mediators and are effective at bringing a flare under control. But adverse effects such as skin thinning have led to much ‘steroid phobia’. Nevertheless, short-term use for one to two weeks is normally sufficient to bring a flare under control without any problems.
The topical calcineurin inhibitors, pimecrolimus and tacrolimus, are immunosuppressive agents. There is little convincing evidence that they are more effective than topical steroids, although they have the advantage of not causing skin thinning and are therefore suitable for sites where there is a risk of skin thinning on prolonged use, such as the eye-lids and face.
Other treatment options
- Bandage treatments, such as wet wraps, can help protect the skin from scratching, and their occlusive nature allows for enhanced penetration of topical therapies, but the evidence base is poor.
- Oral treatments, such as the immunosuppressants ciclosporin and azathioprine, are normally reserved for more severe cases. The evidence for their effectiveness is limited, and such drugs have a number of potentially serious side effects, requiring careful monitoring.
- Antihistamines, such as chlorphenamine, are often prescribed to help relieve itching but there is little evidence that they are effective.
- Phototherapy with both UVA and UVB is often used in secondary care. Phototherapy is suitable for adults and children, but not for very young children or frail elderly patients who are unable to stand in the UV cabinet.
- Complementary/alternative therapies include Chinese herbal medicine, herbal medicine, homeopathy, hypnotherapy, massage, acupuncture and gamma linolenic acid (evening primrose oil). Although such therapies are popular with some patients, and clinical studies show some promise, in particular with Chinese herbal medicine, further work is required to evaluate such treatments.
- Probiotics based on lactobacillus can improve the severity of eczema, but further studies are required to more clearly define their role.
Dr Rod Tucker
Institute of Health Sciences,
University of Leeds, and a project
guardian for the CPPE dermatology packages
Forms of eczema
- Seborrhoeic eczema;Starts as dandruff which can spread to the forehead, eyebrows, eyelids and sides of the nose. It can also spread to the chest and axillae, groin and the sub-mammary regions. Treatment is with topical anti-fungal therapy, eg ketoconazole cream or shampoo, or if the condition is more widespread, oral treatment with ketoconazole or itraconazole.
- Discoid or nummular eczema;Normally presents as coin shaped itchy and scaly inflamed lesions that tend to occur on the lower legs or arms. Although patches will clear with treatment, the lesions often re-appear or new lesions can develop.
- Pompholyx exzema; Normally seen on the lateral aspects of the fingers and the soles of the feet. Pompholyx appears as tiny flesh coloured blisters that are intensely pruritic and is sometimes worse in hot weather. The cause is unknown and treatment normally requires potent steroids.
- Asteatotic eczema; When present on the shins and lower legs, the condition looks very much like crazy-paving or a dry riverbed. Treatment involves the use of greasier emollients, although mild steroids are sometimes required if the condition becomes sore or very itchy.
- Seborrhoeic eczema;Often present in infants as cradle cap. The condition sometimes reappears in teenagers, more so in males than females. Seborrhoeic eczema is a chronic, relapsing-remitting problem.
- Discoid or nummular eczema;Discoid eczema can affect anyone but is more common in middle-aged men. The cause is unknown and the treatment often requires potent steroids, sometimes combined with antibiotics if a secondary infection is present. Discoid eczema can take months or even years to clear completely.
- Pompholyx exzema;Also referred to as dyshidrotic eczema. Without treatment, it can last for about three weeks, but tends to follow a relapsing/remitting pattern for several months or even years.
- Asteatotic eczema;Tends to occur in the lower legs (although it can occur on the arms and torso) and mainly affects patients over the age of 60. More common in the winter months and associated with very dry skin. The cause is unknown but probably related to reduced humidity and use of soaps and shower gels.
Emollients and how to use them
Leave-on emollients such as creams, lotions and sprays are oil and water emulsions, and the higher the proportion of oil, the greasier the product feels on the skin. Most leave-on products will contain preservatives that can cause sensitivity reactions, characterised by a burning, stinging or itching sensation. In contrast, ointments do not contain preservatives and are less likely to cause sensitivity reactions. Examples of emollients in terms of greasiness are:
- Very greasy – Epaderm ointment, 50:50 WSP:LP;
- Greasy – Unguentum M, Hydromol;
- Moderately greasy – Diprobase, Cetraben;
- Light – Aveeno, E45.
Patients should use emollients as often as needed and they should have the opportunity to try different products in order to find one that they find suitable. Emollients should be used liberally. As a rough guide, 2g is equivalent to a teaspoon (5g is a tablespoon) and the amount needed for the treatment of both arms or legs, applied at least twice a day for a week would be up to 200g of cream. Treatment of the trunk alone would require 400g of cream (assuming at least twice daily application).
Washing in the bath or shower on a daily basis is recommended by some specialists to reduce the level of dead skin cells, since this lessens the risk of infection. The temperature of the bath or shower should be warm but not hot, since this increases vasodilatation which can irritate the skin. Although there are several commercial emollient wash products available, soap substitutes such as aqueous cream or Epaderm are equally effective.
Emollients should be applied within a few minutes of bathing to trap surface moisture. The product should be applied to the skin in smooth downward strokes (following the direction of hair growth) and allowed to soak into the skin. Rubbing the product into the skin creates friction which is likely to increase irritation.
The application of emollients in relation to topical steroids is controversial, but provided that a suitable gap is left between applying either preparation it doesn’t really matter whether steroids are applied before or after emollients. In general, emollients should be prescribed in a ratio of 10:1 to topical steroids.
Using topical corticosteroids
There are four classes of topical steroids and the classifi cation is based on steroid potency (not concentration), which is measured by the degree of vasoconstriction produced in the skin:
- Mild – hydrocortisone acetate (Efcortelan 0.1 – 2.5%)
- Moderate – clobetasone 0.05% (Eumovate),betamethasone valerate 0.025% (Betnovate RD)
- Potent – betamethasone valerate 0.1% (Betnovate), hydrocortisone butyrate 0.1% (Locoid), mometasone furoate 0.1% (Elocon)
- Very potent – Clobetasol 0.05% (Dermovate)
There are several potential side effects from topical steroid use, and the effect that gives greatest concern is skin thinning. This is unlikely to occur with the mild to moderate potency agents, but it can occur when the more potent agents are applied over prolonged periods of time. Caution is also needed when potent agents are required for use over large areas of the body, or if used under occlusion since this will enhance their absorption.
Fear of side effects is a major reason for treatment failure, as patients become wary of using steroids appropriately. The amount of steroid to use is normally expressed in terms of the fingertip unit (FTU). This is the amount expressed from the tip of an adult index finger to the fi rst crease.
One FTU is sufficient for the surface area of skin covered by two adult palms (including the fingers). But in practice the FTU scale can be difficult to gauge and it is often better to explain to patients to apply sufficient steroid to give the skin a slight glisten.
Patient education is important and they should understand where particular products should be used. For example, mild to moderate steroids are reserved for the face and flexures, whereas more potent agents can be used on the trunk and arms or legs, provided use is restricted to one to two weeks. Steroids should be reserved for flares, and patients should switch to emollients once a flare has been brought under control.
Patients may also read on packaging that steroids should not be used on broken skin. Since eczema is associated with itch, the skin is invariably broken, presenting something of a dilemma. Broken skin in the context of steroids means surgical wounds or leg ulcers – they are perfectly safe to apply to excoriated, broken skin. Topical steroids are designed to be applied once or twice daily and there is no benefi t derived from more frequent application. Patients need to understand that steroids are not emollients and should not use steroids for their emollient effect.