Here is an expert analysis from Dr. Kiran Godse and Dr. Anant Patil, on the diagnosis and management of atopic dermatitis- focusing on current topical therapies and systemic agents.

Atopic dermatitis, also known as atopic eczema, is a common chronic pruritic inflammatory skin condition encountered in clinical practice. The condition affects up to 25% children. In adults, it affects about 2 to 3% population. It is often observed in people having personal or family history of allergic conditions such as food allergy, allergic rhinitis, or asthma. Atopic dermatitis is associated with significant healthcare burden and impairment of quality of life (QoL).

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Diagnosis of atopic dermatitis

Currently, no reliable biomarkers are available for the diagnosis of atopic dermatitis. Diagnosis is based on the clinical presentation and examination findings. Morphology and distribution of skin lesions play an important role in diagnosis too. Diagnostic criteria by Hanifin and Rajka consisting of 4 major and 23 minor criteria are commonly used in the diagnosis. Presence of three major and three minor criteria are required for the diagnosis of atopic dermatitis. 

Some patients may need laboratory diagnostic tests for the assessment of prognosis. Similarly, tests may be performed for the identification of triggers and assessment of response to prescribed treatment. Some of the laboratory investigations performed in patients with atopic dermatitis include estimation of serum total immunoglobulin E (IgE) levels, specific IgE levels and eosinophil count.

Elevation of total IgE is a very common finding in patients with extrinsic type of atopic dermatitis. Although, this test is not diagnostic of atopic dermatitis, it can assist the clinician in the assessment of prognosis or in selection of appropriate treatment. Generally, in adults, a total serum IgE level of >200 IU/mL may be considered high. Peripheral eosinophil count is not recommended for routine use in the diagnosis of atopic dermatitis.

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Management of atopic dermatitis

The goals of management include:

• Providing relief from the symptoms
• Prevention of symptoms
• Improvement in the quality of life

The approach to treatment is selected based on the severity of condition. Important aspects of the management of atopic dermatitis include:

• Patient education
• Avoidance of trigger factors
• Improvement of the barrier function
• Management of inflammatory conditions

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Topical treatment

Moisturisers and cleansers

Moisturisers are the mainstay of treatment in atopic dermatitis. These agents are useful during acute flares as well as for prevention of relapse and in all types of atopic dermatitis. The agents include humectants, occlusives, and emollients. The moisturiser can be selected based on the environmental condition and patient acceptance and these factors are important for improvement in patient compliance. Patients should be advised to use moisturisers immediately after bath for at least 2 to 3 times every day.

Crusted skin should be carefully removed to eliminate bacterial contamination. The use of antiseptic while bathing does not provide benefit. Patients should avoid strong scrubbing with a bath towel after taking bath. Patients may use neutral to low pH and fragrance-free non-soap cleansers.

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Topical corticosteroids

In patients not responding to appropriate skin care and use of moisturisers, topical corticosteroids can help in controlling flares. However, they should not be used in the long term considering their risk of side effects such as hypothalamic-pituitary-adrenal axis suppression in children and skin-related side effects in patients using potent steroids for longer time periods. In most patients steroids with mild potency are enough. If the patient does not respond to mild potency steroids, causes for reduced efficacy should be evaluated.

Patients should be educated on proper use of topical steroid and avoidance of misuse. Selection of appropriate topical formulation is also important in the management of atopic dertmatitis. For example, lotion and gel are good options for skin with exudation and blisters, and hairy areas, whereas ointment can be used for thick and dry areas. Clinicians should educate patients on the method of topical application with fingertips.

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Topical calcineurin inhibitors

Topical calcineurin inhibitors via their effect on T-lymphocyte function, reduce the inflammatory response. The examples of topical calcineurin inhibitors inhibitors include Tacrolimus and Pimecrolimus. These agents are used in patients who do not respond to steroids, those who experience steroid-related severe adverse events and for use on sensitive body parts like the face, or anogenital regions. They can also be useful in children. Topical corticosteroids are typically used before use of these agents. In some patients both topical corticosteroid and topical calcineurin inhibitor may be required. Cost and chances of topical skin reactions such as burning and stinging are some of the limitations for use of these agents.

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Phototherapy

Phototherapy can be used after the failure of first-line treatment. It can be useful in patients with significant impact on quality of life, and in patients with chronic disease and severe disease. UV therapy may help due to its local anti-inflammatory and immunosuppressive action. High dose UVA1 is also useful for control of acute exacerbations while PUVA (Psoralen + UVA) lights are effective in patients having active stable disease. Phototherapy should be given under the guidance and supervision of an expert.

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Systemic agents

Systemic immunomodulatory agents may be used in patients who do not respond to conventional therapy or those with severe condition affecting large body surface area where use of topical therapy is not possible. Generally, patients requiring systemic therapy should be treated by a dermatologist.

Examples of systemic agents used in atopic dermatitis include:

• Systemic corticosteroids
• Cyclosporine
• Azathioprine
• Methotrexate
• Mycophenolate mofetil

Systemic steroids

Systemic steroids (e.g. prednisolone, dexamethasone, methylprednisolone, betamethasone etc.) should be avoided as far as possible. They should only be used only in patients with severe exacerbation or as a bridge therapy while using other systemic agents.

Dose: Systemic steroids should be used at minimal dose and for the shortest possible duration. Patients should be educated about the risk of adverse events and risk of rebound flares after discontinuation of treatment.

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Cyclosporine

Cyclosporine is an immunosuppressant which can be significantly effective in improving chronic severe atopic dermatitis.

Dose: 150 to 300 mg per day in adults; 3 to 6 mg/kg/day in children

Cyclosporine should also be given at the lowest effective dose and the shortest period. Important side effects with use include- risk of infection, renal toxicity, hypertension, and increased risk of skin cancer and lymphoma. Baseline and regular monitoring of blood pressure is required for patients receiving cyclosporine. Renal and liver function monitoring is also needed. Patients should be tested for tuberculosis at baseline and then annually. At baseline, patients should be tested for HIV and HCG if needed.

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Azathioprine

Azathioprine, a purine analog that inhibits DNA synthesis can be used as a first-line systemic agent in older children and teenagers with chronic long-term moderate to severe AD with high total IgE when cyclosporine is neither effective nor indicated.

Dose: 1-3 mg/kg/day; 1-4 mg/kg in children

At baseline patient should be tested for complete blood count, differential count, platelets, renal function, liver function, hepatitis B and C and tuberculosis. If needed HIV and HCG testing should also be done.

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Methotrexate

Methotrexate, an antifolate metabolite is less immunosuppressive and has preferable long-term safety profile.

Dose: 7.5 to 10 mg every week; 0.2 to 0.7 mg/kg per week in children

It can cause gastrointestinal upset and bone marrow suppression. Long-term adverse events of methotrexate include liver fibrosis, and risk of effect of spermatogenesis and ovulation. Patients should be monitored for complete blood count, differential blood count, platelet count, renal functions, liver functions, hepatitis B and C, and tuberculosis. HIV and HCG, and pulmonary function tests should also be done if indicated.

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Mycophenolate mofetil

Mycophenolate mofetil is useful in patients when other systemic therapies cannot be used. It can use gastrointestinal adverse events in some patients. Monitoring can be done with complete blood count, differential blood count and liver and kidney function tests.

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Antibiotics and antivirals

Antibiotics are required in patients with secondary bacterial infection. Long-term use of antibiotic is associated with risk of increasing resistance. Topical antibiotics given for 7-10 days may be useful for the treatment of local bacterial infections. Antiviral agents- Acyclovir and Valacyclovir are needed in patients with eczema herpeticum.

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Antihistamines

Short-term, intermittent use of sedating antihistamines may be beneficial in some patients, but non-sedating oral antihistamines or topical antihistamines do not have significant role in the management of atopic dermatitis.

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Complementary or alternative therapy

Complementary or alternative therapies do not have strong evidence for use in atopic dermatitis. Unknown ingredients in such formulations may contribute to flare of hypersensitivity reaction.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author, Dr. Kiran Godse is a Professor of Dermatology.