How should I treat dyshidrotic (pompholyx) eczema presenting as an itchy rash on the sole of my foot?

Treatment of Dyshidrotic Eczema on the Sole of the Foot

Apply a potent topical corticosteroid (such as triamcinolone acetonide or clobetasol propionate 0.05%) twice daily to the affected sole for 2–4 weeks, combined with aggressive emollient therapy immediately after bathing. 1, 2

Initial Topical Corticosteroid Strategy

• Use a potent or moderate-potency topical corticosteroid applied no more than twice daily to the vesicular or bullous lesions on the sole, as the thick plantar stratum corneum requires higher-potency preparations to achieve adequate penetration. 1, 2

• Select ointment formulations for the sole because they provide maximal drug penetration through the thick horny layer characteristic of plantar skin. 1

• Continue treatment for 2–4 weeks until vesicles resolve, then transition to twice-weekly proactive maintenance dosing on previously affected areas to prevent recurrence. 1

• After initial clearance, implement "steroid holidays" to minimize the risk of systemic absorption and HPA-axis suppression, particularly when treating large surface areas. 1, 3

Essential Adjunctive Emollient Therapy

• Apply emollients liberally and immediately after bathing (within 10–15 minutes on damp skin) to create a surface lipid film that reduces transepidermal water loss and restores barrier function. 1

• Continue aggressive emollient use even during clear periods because this provides steroid-sparing benefits and extends recurrence-free intervals. 1

• Use soap-free cleansers instead of regular soaps, which strip natural lipids and worsen the barrier dysfunction underlying pompholyx. 1

Monitoring for Secondary Bacterial Infection

• Watch for increased crusting, weeping, purulent exudate, or pustules that signal secondary Staphylococcus aureus infection, which is common in vesiculobullous pompholyx. 1

• If bacterial superinfection is confirmed, prescribe oral flucloxacillin (or erythromycin for penicillin allergy) while continuing topical corticosteroids concurrently—do not withhold anti-inflammatory therapy during appropriate antibiotic treatment. 1, 4

• Obtain bacterial cultures if the skin fails to improve after initial antibiotic therapy to guide targeted antimicrobial selection. 1

Escalation for Recalcitrant or Severe Pompholyx

• If vesicles are bullous or cover large areas of the sole and fail to respond to potent topical corticosteroids after 4 weeks, consider systemic therapy including oral corticosteroids for short-term crisis management, systemic immunosuppressants (methotrexate 7.5–25 mg/week, mycophenolate mofetil up to 3.5 g daily), or alitretinoin for chronic recalcitrant cases. 1, 2, 5

• Phototherapy options include topical PUVA (methoxsalen plus UVA), high-dose UVA-1, or narrowband UVB (312 nm), reserved for patients who have failed adequately potent topical corticosteroids and consistent emollient use. 1, 2, 6

• Intradermal botulinum toxin A injection is an emerging option for recalcitrant pompholyx, particularly when hyperhidrosis is a contributing factor. 2, 6

Identifying and Addressing Potential Triggers

• Perform patch testing (e.g., North American Contact Dermatitis Group Standard Series) if pompholyx is recurrent, recalcitrant, or if there is suspicion of metal allergy (nickel, cobalt, chromate), as metal sensitization is an important etiologic factor in some patients. 1, 7, 5

• Evaluate for hyperhidrosis because excessive sweating is associated with pompholyx flares; managing sweating may reduce recurrence frequency. 8, 7

• Avoid known irritants and allergens identified through history or patch testing, and maintain a cool environment to prevent excessive sweating. 1

Common Pitfalls to Avoid

• Do not use low-potency corticosteroids (e.g., hydrocortisone 1%) on the sole—the thick plantar stratum corneum requires moderate-to-potent preparations for adequate therapeutic effect. 1, 2

• Do not discontinue topical corticosteroids when bacterial infection is present; continue them alongside appropriate systemic antibiotics to maintain anti-inflammatory control. 1

• Avoid continuous daily use of very potent corticosteroids beyond the initial 2–4 week treatment period; shift to twice-weekly maintenance to reduce adverse effects such as HPA-axis suppression. 1, 3

• Do not apply occlusive dressings to large areas of potent corticosteroid application without close monitoring, as this augments systemic absorption and increases the risk of HPA-axis suppression and Cushing's syndrome. 3

When to Refer or Escalate

• Refer to dermatology if pompholyx does not respond to moderate-to-potent topical corticosteroids after 4 weeks of appropriate use. 1

• Seek specialist management when systemic therapy (phototherapy, oral immunosuppressants, alitretinoin, or biologics) is contemplated. 1, 2

• Obtain urgent evaluation if grouped vesicles, punched-out erosions, or sudden deterioration with fever occur, as these findings suggest eczema herpeticum—a medical emergency requiring immediate intravenous acyclovir. 1, 4