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Eczema: an essential picture guide for GPs

01 Aug 2006

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Eczema or dermatitis refers to a chronic inflammatory skin condition associated

with itching. This group of disorders consists of atopic eczema, allergic and irritant contact eczema, as well as a group of heterogeneous eczematous skin disorders. It is characterised by poorly defined areas of erythema with vesicles and scaling with lichenification in its chronic stage.

Atopic eczema

This is an increasingly common skin condition affecting up to 20 per cent of children in the UK and other developed countries. Onset of disease is before the age of five years in 70-90 per cent of cases. Approximately 60 per cent are symptom-free by adolescence but up to 50 per cent have recurrent disease in adulthood.

The cause of atopic eczema is unknown but genetic and environmental factors play a role. Investigations are rarely necessary and diagnosis is usually based on clinical features. Diagnostic guidelines see table 1 on page 39.

Skin prick tests or radioallergosorbent tests for type 1 allergies to food and environmental allergens are not routinely carried out as their contribution to atopic dermatitis is not predictable even if positive. It is unclear if patch testing to airborne allergens is useful.

Mild to moderate

atopic eczema

• Emollients are very effective in improving dry skin atopic eczema and should be used on a continuous basis. However, there is a lack of evidence from clinical trails to support this, but it is widely accepted that emollients improve the dry skin associated with atopic eczema. Compliance with treatment is improved if patients and their carers are given the opportunity to try different emollients and use the emollient of their choice.

• Topical steroids are the first-line treatment for flare-ups of atopic eczema. Ointments are generally preferable to creams. The strength of steroid used is determined by the body site, age of patient and severity of eczema. The weakest possible steroid which controls the eczema should be used once to twice daily for ten to 14 days to obtain clearance, then in bursts of three to seven days for flares. In general, mild and moderately potent steroids are used on the face and genital areas. The concern of patients and their carers regarding skin thinning due to topical steroids is often out of proportion to the true risk.

• Topical calcineurin inhibitors have been shown to be effective in atopic eczema and do not cause skin thinning. Their use has been approved by NICE for the second-line treatment of atopic eczema in adults and children above the age of two. Topical tacrolimus 0.03 per cent ointment for moderate to severe disease and topical pimecrolimus 0.1 per cent cream for mild to moderate disease. Topical tacrolimus

0.1 per cent is approved for use in adults above the age of 16 only.

The Food and Drug Administration has highlighted a potential link between the use of topical immunomodulators and the development of skin and internal cancers based on animal studies and case reports. On the other hand, five-year studies have shown a good safety profile for these topical calcineurin inhibitors.

Chronic lichenified eczema

Lichenification (accentuated skin markings) is a feature of chronic eczema. More potent topical steroids for longer periods of time may be required.

• Wet wraps are used to enhance the effects of emollients and topical steroids in chronic eczema. A double layer of cotton tubular bandages or garments are put on over emollients or topical steroids. The inner layer is moistened but the outer layer is dry. There is little evidence to support their use but they are very effective for selected patients, especially those with very dry skin.

• Psychological factors. It is important to take into account the adverse psychological effect of chronic eczema on the patient and their carers. This may affect their motivation to persevere with treatment. Input from a clinical psychologist may be helpful.

Severe atopic Eczema

In patients who fail to respond to conventional therapy, it is important to consider the social and psychological factors that may contribute to poor compliance with treatment. Patch testing may be useful to exclude super-added allergic contact dermatitis.

• Phototherapy. Both PUVA (psoralen and UVA) and narrow band UVB have been shown to be effective for the treatment for atopic dermatitis. In the short term, there is a risk of burning and flare of eczema. Long-term repeated courses are associated with an increased risk of skin cancer.

• Immunosuppressive agents. Short courses of oral steroids are used in clinical practice and are effective. Long-term use is limited by side-effects. Their use has not been compared to other immunosuppressive agents in randomised controlled trials.

Other systemic treatments used in clinical practice include azathioprine and cyclosporin. They require close monitoring due to serious adverse effects and should be reserved for patients under hospital supervision.

Infected eczema

Skin affected with eczema is often colonised with Staphylococcus aureus. Erythematous, exudative and crusted lesions suggest active infection. It is usually treated with short courses of

oral antibiotics such as flucloxacillin or cephalosporins. There is no good evidence that combinations of topical antibiotics and steroids are superior to topical steroids alone.

In patients with recurrent infections, nose swabs may be taken. If they are positive for S. aureus on culture, a course of topical mupirocin may be used to eradicate colonisation.

Eczema herpeticum

Eczema herpeticum presents with widespread multiple monomorphic haemorrhagic or crusted papules on a background of atopic eczema. Patients are often systemically unwell. Early treatment with antiviral therapy such as oral acyclovir is advised. Hospital admission may be necessary.

Eyelid eczema

Eyelid eczema is often a feature of atopic eczema, and can be difficult to manage. If mildly potent topical steroids are unable to control the problem, topical calcineurin inhibitors are indicated. In older children and adults, allergic contact dermatitis may be a cause and patch testing should be considered.

lip licking eczema

This is a local irritant eczema seen in children who have a habit of licking their lips. This can be treated with emollients and mildly potent topical steroids but habit reversal is the key to the problem.

Juvenile plantar dermatosis

This occurs in children who spend long periods of time in shoes and trainers. It is characterised by a shiny, glazed

erythema with some scaling. The condition tends to persist through childhood. Paraffin-based emollients may help but this is not supported by

evidence. Topical steroids are usually unhelpful. An important different diagnosis is allergic contact dermatitis to rubber or chemical in leather.

Hand eczema

Hand eczema is characterised by erythema, vesicles, fissures, scaling and hyperkeratosis. It is a common condition with a one-year prevalence of up to 10 per cent among adults and higher in occupations such as hairdressers and bakers. Causes include atopic, irritant and allergic contact dermatitis. It is also important to consider fungal infection as a cause, especially if the condition is unilateral. Investigations to consider include skin scrapings and patch tests. Reduction of exposure to irritants and avoidance of allergens is essential. Practical measures such as wearing gloves and using soap substitutes are often advocated. Topical steroids and phototherapy (most commonly topical psoralen and UVA) are effective treatment options.

asteototic eczema

Asteotosis refers to dry skin. The main causes include age, dry climate and excessive washing. Patients with atopic dermatitis, renal impairment, malnutrition and ichthyosis vulgaris are also predisposed to asteototic dermatitis. Dry scaly skin with superficial fissures with the appearance of 'crazy paving' is characteristic. The use of soap substitutes and emollients, as well as avoidance of over-washing is crucial. Topical steroids in short bursts may be needed in some patients.

varicose eczema (or Stasis dermatitis)

This is a common condition due to chronic venous hypertension, affecting approximately 1 per cent of the European adult population. Prevalence rises with age. Associated physical signs include pitting oedema, discolouration of the skin due to haemosiderin deposition and venous ulcers. Management of venous hypertension with measures such as compression hosiery or bandaging is of utmost importance. Treatment of the eczema is with emollients or bursts of topical steroid. If the eczema does not respond to treatment, patch tests to exclude super-imposed allergic contact dermatitis should be considered.

discoid eczema/

nummular dermatitis

This form of eczema is characterised by disc-shaped scaly erythematous lesions that usually affect the limbs. It may be associated with atopic dermatitis, varicose eczema or asteototic eczema. Tinea corporis is an important differential diagnosis. Treatment options include moderate- to high-potency topical steroids, topical calcineurin inhibitors or phototherapy.

seborrhoeic dermatitis

This is a highly prevalent eczematous condition with a predilection for the face, scalp, chest and intertriginous areas. It may present in early infancy with scaly patches on the scalp known as 'cradle cap'. It is uncommon in later childhood but again occurs commonly in adult life.

The affected skin may be mildly itchy with erythema and 'greasy' scaling. This condition may be linked to the number of or abnormal reaction to the skin commensal, Malassezia sp. (Pitysporum ovale). Topical azoles such as clotrimazole or miconazole are effective but this condition can recur within weeks and repeated treatments are often necessary. Ketoconazole shampoo used once weekly may be effective for maintenance therapy. Topical calcineurin inhibitors may be considered for resistant cases. In very severe cases, underlying immunodeficiency should be considered.

References

1 Hoare C, Li Wan Po A et al. Systematic review of treatments for atopic eczema. Health Technol Assess 2000;4(37):1-191

2 National Institute for Clinical Excellence. Final appraisal determination for frequency of application of topical steroids for atopic eczema. Available at nice.org.uk/page.aspx?o=115554

3 National Institute for Clinical Excellence. Final appraisal determination: tacrolimus and pimecrolimus for atopic eczema. Available at nice.org.uk/page.aspx?o=TA082

USEful websites

1 More information and additional links for doctors and patients are available from the Skin Conditions Specialist Library of the National Library for Health www.library.uk/skin

2 Information on support group for patients in the UK is available on www.eczema.org

REFERENCES

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