What is the pharmacological approach to atopic dermatitis (eczema)?

Pharmacological Management of Atopic Dermatitis (Eczema)

Start with liberal emollient use combined with the least potent topical corticosteroid that achieves disease control, applying no more than twice daily to affected areas only. 1, 2

First-Line Pharmacological Therapy

Topical Corticosteroids

• Use topical corticosteroids as the mainstay of treatment, selecting potency based on disease severity, patient age, and anatomical site 2, 3
• For mild eczema, begin with low-potency preparations like hydrocortisone 1% 2, 4
• For moderate disease, use low to medium potency corticosteroids 4
• For severe flares, employ medium to high potency corticosteroids for short courses of 3-7 days only 4
• Apply a thin layer to affected areas once or twice daily—more frequent application does not improve efficacy but increases adverse effects 2, 4
• Implement "steroid holidays" by stopping corticosteroids for short periods when control is achieved to minimize cumulative exposure and reduce risk of hypothalamic-pituitary-adrenal axis suppression 1, 4

Site-Specific Considerations

• For face, neck, and intertriginous areas, use only low-potency corticosteroids (hydrocortisone 1%) to avoid skin atrophy 4, 3
• For body and limbs, select potency based on severity 4
• Very potent and potent preparations should be reserved for limited periods on thick-skinned areas only 1, 3

Emollients as Essential Co-Therapy

• Prescribe adequate quantities of emollients and instruct patients to apply liberally and frequently, as they provide a surface lipid film that retards evaporative water loss 1, 2, 3
• Apply emollients immediately after bathing to maximize hydration 2, 3
• Replace traditional soaps with soap-free cleansers or dispersible cream cleansers to preserve natural skin lipids 1, 3

Alternative Topical Agents

Topical Calcineurin Inhibitors

• Pimecrolimus 1% cream and tacrolimus ointment (0.03% for children, 0.1% for adults) are effective steroid-sparing alternatives, particularly for sensitive areas like the face and genitals 4, 5, 6
• These agents inhibit T-cell activation by blocking calcineurin-dependent cytokine transcription 5
• Use as first-line treatment in conjunction with topical corticosteroids or as monotherapy for facial eczema 4, 6

Coal Tar and Ichthammol

• Ichthammol 1% in zinc ointment is less irritant than coal tar and particularly useful for lichenified eczema 1, 4
• Coal tar solution 1% in hydrocortisone ointment is adequate and does not cause systemic absorption unless used extravagantly 1

Management of Pruritus

• Prescribe sedating antihistamines (such as hydroxyzine) for nighttime use only during severe pruritus episodes, as their therapeutic value resides in sedative properties, not direct antipruritic effects 1, 2, 4
• Large doses may be required in children 1
• Non-sedating antihistamines have little to no value in atopic eczema and should not be used 1, 2, 4
• Avoid daytime use of sedating antihistamines 2
• Note that hydroxyzine is contraindicated in early pregnancy 2

Treatment of Secondary Infections

Bacterial Infections

• When you observe increased crusting, weeping, or pustules, initiate oral flucloxacillin immediately as the first-line antibiotic for Staphylococcus aureus, the most common pathogen 1, 4, 3
• Use phenoxymethylpenicillin if β-hemolytic streptococci are isolated 1
• Prescribe erythromycin for penicillin-allergic patients or flucloxacillin resistance 1, 4
• Continue topical corticosteroids during bacterial infection when appropriate systemic antibiotics are given concurrently—do not delay or withhold corticosteroids 3

Viral Infections (Eczema Herpeticum)

• If you observe grouped vesicles, punched-out erosions, or sudden deterioration with fever, suspect eczema herpeticum and initiate oral acyclovir immediately—this is a medical emergency 1, 4, 3
• In ill, feverish patients, administer acyclovir intravenously 1, 4, 3
• Send swabs for virological screening and electron microscopy to confirm diagnosis 4, 3

Second-Line and Systemic Therapies

Phototherapy

• Narrow-band ultraviolet B (312 nm) is effective for moderate to severe disease when topical therapies fail 1, 6
• PUVA may be used but carries concerns about premature skin aging and cutaneous malignancies with long-term use 1

Systemic Corticosteroids

• Reserve oral corticosteroids only for acute severe flares requiring rapid control after exhausting all other options—they should "tide over" occasional patients during crises, not serve as maintenance therapy 1, 2, 3
• The decision to use systemic steroids should never be taken lightly due to risk of pituitary-adrenal suppression and potential growth interference in children 1, 2

Biologic Therapy

• Dupilumab (an IL-4 receptor alpha antagonist) administered as 600 mg subcutaneously at Week 0, followed by 300 mg every 2 weeks, is highly effective for moderate-to-severe atopic dermatitis 7
• In clinical trials, 36-38% of adults achieved clear or almost clear skin (IGA 0 or 1) at 16 weeks compared to 9-10% with placebo 7
• When combined with topical corticosteroids, 39% achieved clear or almost clear skin versus 12% with placebo 7

Newer Topical Agents

• Roflumilast (a PDE-4 inhibitor) offers a non-steroidal option better positioned for maintenance therapy or as a corticosteroid alternative rather than acute flare management 2
• Crisaborole is another topical PDE-4 inhibitor effective for atopic dermatitis but currently cost-prohibitive 6

Common Pitfalls to Avoid

• Do not undertreate due to steroid phobia—explain different potencies and the risk-benefit profile clearly to patients and parents 1, 4
• Do not use topical corticosteroids continuously without breaks 3
• Do not apply corticosteroids more than twice daily, as this increases adverse effects without improving efficacy 1, 2, 4
• Do not prescribe non-sedating antihistamines for itch control in atopic dermatitis 1, 2, 4
• Do not delay antibiotics when secondary bacterial infection is present 3

When to Refer or Escalate

• Failure to respond to moderate-potency topical corticosteroids after 4 weeks of appropriate use 3
• Need for systemic therapy or phototherapy 3
• Suspected eczema herpeticum (immediate referral required) 3
• Deterioration despite appropriate topical therapy and systemic antibiotics 3