The Australasian Society of Clinical Immunology and Allergy

Atopic dermatitis (eczema) is a chronic pruritic skin condition associated with elevated IgE antibodies. It most commonly begins during infancy and early childhood.

Introduction

Atopic dermatitis commonly begins during infancy and early childhood years. This infantile form usually involves extensor surfaces of the extremities, the face, the trunk, and the neck. As the patient ages, the disease shows a predilection for the flexural aspects of the antecubital fossa and the popliteal fossa. With the progression into adulthood, this particular propensity for itching persists and patients frequently develop a chronic hand eczema which may be further aggravated by occupations which require frequent wet work, frictional work, or exposure to chemicals. New onset adult atopic dermatitis usually occurs in the setting of demonstrable atopy with markedly elevated total IgE and positive skin tests or positive aeroallergen-specific IgE using allergen specific IgE (RAST) testing.

Natural History

Many children with atopic dermatitis will outgrow their eczematous dermatitis. However, severe atopic dermatitis extending into adolescence usually portends atopic dermatitis throughout adulthood. The trigger may change. For example, children tend to lose food allergies; and adults in occupations with exposure to irritants and chemicals may have particularly recalcitrant disease. It is advisable, therefore, that these important factors be considered in the context of career guidance during adolescence and may be very helpful in minimising future disease severity in young adults.

Diagnosis

The diagnosis of atopic dermatitis is ultimately dependent on a constellation of features. Major clinical features include

• Pruritis;
• Early age of onset;
• Typical morphology i.e. flexural lichenification or thickening of the skin and hyperlinearity of the palms, facial extensor involvement in infants and young children;
• Chronic or chronically relapsing dermatitis;
• A personal or family history of atopy or allergic disease;

There are many diseases which may result in an eczematous dermatitis including several immunodeficiency diseases, metabolic disorders, neoplastic syndromes, paraneoplastic syndromes, chronic eczematous dermatosis secondary to such things as allergic contact dermatitis, psoriasis, and seborrhoeic dermatitis.

Triggers

The symptoms of atopic dermatitis are triggered by a plethora of potential aggravants, both allergic and non-allergic. During the warm summer months, occupational exposure to heat and increased humidity may provoke intense itching. During the winter months, increased skin dryness may be a significant contributor to intractable itching. Research studies have also shown a relationship between exacerbation of lesions of atopic dermatitis and exposure to house dust mite.

Foods are also possible triggers in some patients with atopic dermatitis, although this is of greater significance in childhood atopic dermatitis. Certain foods appear to be more common culprits than others: Egg, milk, peanuts, soybean, and wheat are the most common foods causing a flare of atopic dermatitis in children. Foods are probably not a major trigger for atopic dermatitis in adults. In these cases, prick skin testing or RAST testing to relevant foods should be performed.

Treatment

Patient compliance and co operation are essential in the successful management of atopic dermatitis.

ASCIA has developed action and care plans that are available to print off for your patients from the ASCIA website www.allergy.org.au/content/view/295/236/

Corticosteroids are the mainstay of treatment in conjunction with emollients to help promote hydration of the skin. There have been many advances in the pharmacology of topical corticosteroids. The majority of the currently available corticosteroid preparations, are divided into classes, by potency. The potent fluorinated corticosteroids should be avoided on the face, the genitalia, and the intetriginous area. A hydrocortisone preparation should be used instead in these area. The goal of treatment is to use emollients and low potency corticosteroids for maintenance therapy and to use the mid- and high -potency corticosteroids for short periods of time to address clinical exacerbations.

Most patients with atopic dermatitis have dry xerotic skin which contributes to the disease morbidity in addition to creating microfissures and cracks in the skin which may serve as a portal of entry of skin pathogens. This problem may become exacerbated during the winter months. Hydration of the involved skin is critical. The careful adherence to these treatment regimes may give the patient excellent symptomatic relief. Short, 15 to 20 minute, soaks in a tepid bath sometimes using a colloidal oatmeal, bath oils or Oilatum with triclosan are recommended. Caution the patient that the use of excessive hot water or extended submersion times may actually aggravate the condition rather than help. Immediately after leaving the bath, the patient should pat dry, using a soft towel. Rubbing the skin dry can cause unnecessary irritation. As soon as the patient is dry, this is followed by application of a hydrophilic cream or occlusive ointment. There are a multiplicity of hydrophilic ointments and emollients which may be used by an atopic dermatitis patient and selection should be individualised based on both patient preference and cost.

Occlusive ointments are sometimes not well tolerated because of interference with the function of the exocrine sweat ducts and may induce the development of a sweat retention dermatitis. Thickening and lichenified plaques of atopic dermatitis and atopic hand dermatitis may however, respond best to a topical steroid in an ointment base.

Skin infections, particularly staph aureus or herpes simplex, may be a recurrent problem requiring specific treatment.

In summary, the Allergist's approach to treating this chronic frustrating disease is to recognise the role of irritant factors such as:

• Heat
• Perspiration
• Wool
• Soaps and disinfectants
• Cigarette smoke

Treatment - main points

• Avoid known irritants. These frequently include chemicals, detergents, soaps, abrasives or occlusive clothes.
• Temperature and humidity control are critical. Extremes of either factor are to be avoided.
• Allergen avoidance for those atopic dermatitis patients with documented allergies is also essential. This includes foods, House Dust mites and animal danders in individuals allergic to these.
• All patients who are not easily controlled with emollients and occasional steroid creams should be assessed for allergic factors by a medical specialist (Allergist / Clinical Immunologist).
• In patients with dust mite allergy, strenuous dust mite avoidance measures need to be carried out, including the removal of carpet in the bedroom.

© ASCIA 2010

The Australasian Society of Clinical Immunology and Allergy (ASCIA) is the peak professional body of Clinical Immunologists and Allergists in Australia and New Zealand.

Website: www.allergy.org.au

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Disclaimer

ASCIA Education Resources (AER) information is reviewed by ASCIA members and represents the available published literature at the time of review. Information contained in this document is not intended to replace professional medical advice and any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner.

Content last updated January 2010