Eczema is the most common skin condition in the UK. although it is most common in children, it can present in adults and has a wide range of causes. This article looks at the types of eczema and their presentation.

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Why read this article?Eczema is the most common skin condition in the UK. although it is most common in children, it can present in adults and has a wide range of causes. This article looks at the types of eczema and their presentation.What is the differential diagnosis?Conditions that can present in a similar way to eczema include psoriasis, scabies and urticaria, rosacea and certain fungal skin infections. these may be differentiated by signs, symptoms, and location on the body. Patients who have not previously been diagnosed or with severe symptoms should be referred.What complications can occur?Eczematous skin can become infected with bacteria or viral infections. Patients with signs of an infection caused by herpes simplex require urgent medical referral as the condition can be life-threatening. Typical signs of eczema herpeticum include grouped blisters and punched-out erosions (which are circular depressed ulcerated lesions and usually have a diameter of 1-3mm), fever, lethargy and worsening, painful eczema.

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Eczema, a form of dermatitis, is the most common skin condition in the UK and affects 15-20 per cent of school children and 2-10 per cent of adults.1 there are various forms of the condition, the most common being atopic eczema. Nice has issued guidance for the management of eczema in children up to 12 years.2 However, these recommendations may be extrapolated to management in older children and adults, as the pathology of the condition is the same.Most types of eczema have an unknown aetiology. However, a major causative factor is an impaired barrier function of the epidermis, which results in increased water loss causing dry cracked skin, and the entrance of irritants and allergens. ClassificationThe classification of eczema tends to be unsystematic, with many synonyms to describe particular types. in addition, eczema and dermatitis are often used interchangeably.Atopic eczema is the most common form of the condition. The term ‘atopic’ refers to a personal or family tendency to develop certain allergies and, consequently, an increased chance of developing other atopic conditions such as asthma and hayfever. 1. Atopic eczema is classed as endogenous as it is due to internal factors. The exact cause is not fully understood, but genetics, environmental triggers, defects in the epidermal skin barrier and immunological responses may be involved. Common trigger factors include the house dust mite (due to a sensitivity to a protein in the faeces of the mite), extremes of temperature and humidity, stress, grass pollens and cows’ milk. See table 1, above right, for a full list of trigger factors. Atopic eczema is typically characterised by pruritic, excoriated, inflamed dry skin, which may be accompanied by exudation. It tends to be chronic and inflammatory, with episodes of flares and remissions, although it may be continuous in very severe cases. The initial acute phase comprises intensely itchy erythematous lesions, which is often accompanied by tiny exudating vesicles that crust. as the skin is infiltrated with inflammatory cells, it can be painful. The subsequent chronic phase may have all of the acute phase features but also exhibit scaling and skin thickening (lichenification). as a rule, inflamed areas of skin tend to flare up from time to time and then settle down. The severity and duration of flares varies between different patients, and from time to time in the same individual. in mild cases, a flare-up may cause just one or two small, mild patches of inflammation, often located behind the knees or in front of elbows or wrists. in severe cases, the flare-ups can last several weeks or more and cover many areas of skin.Most patients present with eczema in early infancy, where it is commonly seen on the cheeks, forehead and external surfaces of the limbs. Around 15 per cent of children develop the condition within the first six months. as the child gets older, facial lesions generally improve and symptoms are more commonly seen on the inner flexures. By adulthood, lesions tend to be more widespread. Around 75 per cent of patients will have a spontaneous remission of the condition by age 15, but may continue to experience dry skin throughout life. 2. Irritant contact dermatitis is an exogenous eczema (caused by external contact factors) and involves a non-immunological response. It is caused by skin contact with irritants (such as household detergents) and results from a direct reaction to the irritant. It is characterised by itchy, erythematous skin, which is dry because the irritant depletes fats and oils from the skin. It is most commonly seen on adult hands but may be misdiagnosed as atopic eczema.3. Allergic contact dermatitis is an exogenous eczema resulting from regular contact with a substance such as nickel jewellery, rubber gloves, perfumes and preservatives. its symptoms are similar to those of irritant contact dermatitis, and it is not possible to distinguish between the two conditions by observation, although allergic contact dermatitis is less common. Allergic contact dermatitis generally develops over a long period of time due to a delayed reaction to an allergen. If the cause is not identifiable, patch and/or prick testing may be performed to aid diagnosis.4. Seborrhoeic eczema is an endogenous eczema, and in adults is commonly associated with overgrowth of the yeast Malassezia. It typically affects the scalp but may also affect ears, eyebrows, face, body, limbs and skin folds. The symptoms of seborrhoeic eczema vary depending on the part of the body affected. If the scalp is affected, crusty scales are typically seen, which is called cradle cap in infants (although this may have a different cause). If the face and eyelids are affected, the skin is dry, itchy and inflamed.5. Varicose eczema is also known as gravitational, stasis or venous eczema. It mainly occurs in older women due to poor circulation, and may be associated with varicose veins and deep vein thrombosis. Typically, it is characterised by erythematous inflammation, scaling and crusting on the lower leg. The foot may appear oedematous and the leg veins may be blue and swollen. Varicose eczema is often misdiagnosed as cellulitis or a venous leg ulcer.6. Discoid (nummular) eczema is an endogenous eczema. It appears as coin-shaped, very itchy, red, scaly patches, and is frequently found on the limbs. The cause is unknown but it mainly affects adults, often in later life.7. Pompholyx (also known as dyshidrosis or vesicular palmoplantar dermatitis) appears on the palms, soles, fingers and toes. It is characterised by recurrent vesicles or large blisters, which appear worse in warm weather.8. Asteatotic eczema (also known as eczema craquele or xerotic eczema) is typically seen on the limbs of elderly patients. It is characterised by dry, cracked, itchy skin, which resembles crazy paving. This type of eczema is commonly caused by conditions that make the skin more susceptible to drying. these include central heating, dry winter weather, hypothyroidism and excessive washing.9. Lichen simplex chronicus (or neurodermatitis) typically presents as a thickened patch of itchy skin. It is caused by continued scratching and rubbing and may be stress-related.DiagnosisPatients who have not been previously diagnosed with atopic eczema or those with widespread or severe symptoms should be referred to their GP (see table 2, right). several other dermatological conditions can be misdiagnosed as eczema:

• Psoriasis can sometimes look like eczema. However, psoriatic plaques are less itchy, with silvery scales and tend to be found on the extensor (outer) surfaces of limbs, whereas eczema commonly affects the flexor (inner) surfaces of limbs.
• Scabies and urticaria can sometimes be confused with eczema as they cause intensely itchy skin. However, scabies typically affects palm creases and finger webs, and other family members may be infected at the same time. Scabies and head lice infestation can also lead to eczematous skin.
• Rosacea is a condition where the skin of the face exhibits papular and/or pustular erythema. It is commonly associated with dilated blood capillaries (telangiectasia).
• Fungal skin infections may be confused with eczema but are often unilateral, whereas eczema tends to be bilateral.

ComplicationsEczematous skin can become infected with staphylococcal and occasionally streptococcal bacteria. Signs of infection include weeping, crusting, severe inflammation, worsening of eczema and lack of response to treatment. Occasionally, a viral infection may occur in the eczematous skin, causing a wart. Patients with signs of an infection caused by herpes simplex (eczema herpeticum) require urgent medical referral as the condition can be life-threatening. Typical signs of eczema herpeticum include grouped blisters and punched-out erosions (which are circular depressed ulcerated lesions and usually have a diameter of 1-3mm), fever, lethargy and worsening painful eczema.Eczema can have considerable impact on the quality of life of patients and parents/carers. Sleep disturbance is common due to the intense itching, especially during flares. in children this can lead to irritability, restlessness and poor concentration in class, which can lead to a misdiagnosis of ADHD.3 Eczema patients are also restricted in their choice of leisure activities and careers.Chinjal Patel MRPharmS PGDip is a community pharmacist in Oadby, Leicester.References

1. CKS. Eczema-atopic. Clinical Knowledge Summaries 2010; cks.nhs.uk/eczema_atopic
2. Nice. Atopic eczema in children. Management of atopic eczema in children from birth up to the age of 12 years. Nice clinical guideline 57. Dec 2007.
3. CKS. Attention deficit hyperactivity disorder. Clinical Knowledge Summaries 2010; cks.nhs.uk/attention_deficit_hyperactivity_ disorder.

Table 1: Trigger factors for atopic eczema

• House dust mites.
• Grass pollens.
• Pet dander and moulds.
• Extremes of temperature and humidity.
• Dietary factors such as dairy products (especially cows’ milk), eggs, fish, soya, nuts, wheat, gluten, tomatoes and citrus fruits.
• Irritants such as detergents, soaps, bubble baths, shampoos, chemicals, perfumes, preservatives and alcohols.
• Stress and hormonal factors.
• Irritating fabrics such as wool and polyester.

Table 2: Diagnostic criteria for atopic eczema 1,2

Atopic eczema is diagnosed when there is itchy skin (or parental report of scratching) plus three or more of the following:

• Visible flexural dermatitis involving the skin creases (eg inner elbow creases or behind the knees) or visible dermatitis on the cheeks and/or extensor areas in children aged 18 months or under.
• A personal history of flexural dermatitis (or dermatitis on the cheeks and/or extensor areas) in children 18 months and under.
• A personal history of dry skin in the previous 12 months.
• A personal history of atopy in a first-degree relative of children under four years.
• The onset of signs and symptoms under the age of two years.

ReflectWho is most likely to suffer from eczema lesions on the face? what are the diagnostic criteria for atopic eczema? how would you recognise a patient with eczema herpeticum?PlanThis article describes the clinical features of the main types of eczema including atopic eczema, irritant and allergic contact dermatitis and seborrhoeic, varicose and discoid eczema. It also discusses trigger factors, diagnosis, differential diagnosis and complications. Act• Find out more information about atopic eczema from the Patient UK website.• Read more about irritant and allergic contact dermatitis on the Patient UK website. • The Patient UK website also has useful articles with more detailed information about seborrhoeic, varicose and discoid eczema at tinyurl.com/eczema03, tinyurl.com/eczema04 and tinyurl.com/eczema05.• Find out more about eczema and infection from the National Eczema Society factsheet.EvaluateAre you now confident in your knowledge of the different types of eczema and their clinical features? are you familiar with the trigger factors and diagnostic criteria for atopic eczema? Could you advise patients about complications that could occur?