Pompholyx

Also called dyshidrotic eczema. It is a vesicular eczema of the palms, the sides of the fingers and the soles, in recurrent attacks. The vesicles are not caused by sweat gland blockage (the old name is misleading), and arise from spongiosis in the epidermis.

• It is common, accounting for about 5 to 20% of hand eczema, usually in people aged 20 to 40 years, and affects women slightly more than men.
• Triggers and associations:
  • Atopic dermatitis (a personal or family history in about 50%).
  • Contact allergy (nickel, cobalt, chromate, fragrance, balsam of Peru) and irritant exposure (wet work, detergents, solvents).
  • Dermatophyte infection elsewhere on the body (an id reaction), especially tinea pedis.
  • Ingested nickel or cobalt (systemic contact dermatitis), drugs (intravenous immunoglobulin, aspirin, oral contraceptives), and smoking.
  • Emotional stress, sweating and hot weather (seasonal flares).
  • Hyperhidrosis in about 40% of patients.
• The course is chronic and relapsing, with each attack lasting 2 to 4 weeks and recurring for years, and it affects work and sleep.

• Sudden onset of intensely itchy or burning, deep seated, tapioca like vesicles (1 to 2 mm), on the sides of fingers, palms and soles, in clusters. Itch or burning often precedes the vesicles by several hours.
• Large blisters (bullae) form in severe flares, particularly on the soles. Vesicles dry over 2 to 3 weeks, with scaling, fissures and lichenification, leaving rough skin.
• Nails develop pitting, ridging, and nail fold swelling after repeated attacks.
• Secondary infection causes pustules, yellow crust, pain and lymphangitis.
• Differential diagnosis: tinea pedis or manuum (unilateral, scaling, positive scraping), allergic or irritant contact dermatitis, palmoplantar pustulosis (sterile pustules, psoriasis association), scabies, bullous pemphigoid (older adults), dermatitis herpetiformis, herpes simplex, hand foot and mouth disease, pustular psoriasis, and bullous drug eruption.
• Complications: secondary infection, painful fissures, nail dystrophy, disability and loss of work, and sleep disturbance.

• Clinical. Examine all skin and the feet and nails for tinea, and ask about work, hobbies, hand washing, jewellery, atopy, and all drugs.
• Scrapings for potassium hydroxide preparation and fungal culture to exclude dermatophyte infection.
• Swab for bacterial culture if pustular, crusted or painful.
• Patch testing (baseline series, plus nickel, cobalt, fragrance, and work related allergens) in chronic or severe disease, and if allergic contact dermatitis is suspected.
• Biopsy and direct immunofluorescence if the diagnosis is uncertain or bullae suggest an autoimmune blistering disease.
• Check glucose, full blood count, and thyroid function in refractory disease, and test for HIV if risk factors exist.

• Avoidance and skin care:
  • Remove contact triggers and irritants. Wear cotton lined, non-latex vinyl or nitrile gloves for wet work, and avoid hot water, soaps and solvents.
  • Use a soap free wash and a thick, fragrance free emollient (white soft paraffin, or urea 5 to 10% cream) after every hand wash and at least 4 to 6 times daily.
  • Use cool compresses and avoid scratching and popping vesicles.
  • Treat hyperhidrosis (aluminium chloride 20% solution at night).
  • A low nickel diet is controversial and of uncertain value (limited evidence). Consider it only after patch testing confirms nickel allergy and the disease persists.
• Acute flare, vesicular or weeping:
  • Soaks with potassium permanganate 1:10,000 or aluminium acetate 5% solution for 10 to 15 minutes, 2 to 3 times daily, until weeping stops.
  • Very potent topical corticosteroid, such as clobetasol propionate 0.05% ointment, once or twice daily for 2 to 4 weeks, then taper to a potent steroid (betamethasone valerate 0.1%) for another 2 to 4 weeks, then stop. Occlusion under cotton gloves at night increases potency.
  • Keep treatment brief and monitor for skin thinning and infection.
• Maintenance and steroid sparing therapy:
  • Tacrolimus 0.1% ointment twice daily for 4 to 12 weeks, or pimecrolimus 1% cream. Burning is common in the first days.
  • Emollient and an intermittent potent steroid, 2 consecutive days weekly, reduces relapse.
• Severe flare: oral prednisolone 0.5 mg/kg per day (30 to 40 mg) for 5 to 7 days, tapered over 2 weeks. Do not use long courses. Intramuscular triamcinolone 40 mg is used by some clinicians (not recommended for repeated use).
• Chronic or refractory disease (specialist care):
  • Phototherapy: psoralen with UVA to the hands and feet (topical or bath PUVA), or narrowband UVB, 2 to 3 times weekly for 6 to 8 weeks.
  • Alitretinoin 10 to 30 mg orally daily for 12 to 24 weeks. It is contraindicated in pregnancy, and a pregnancy prevention programme is mandatory. Monitor lipids, liver tests and thyroid function.
  • Methotrexate 7.5 to 15 mg orally once weekly, with folic acid 5 mg once weekly, taken on a different day from methotrexate. Monitor blood count, liver tests and creatinine.
  • Ciclosporin 3 to 5 mg/kg per day for up to 3 to 6 months, with monitoring of blood pressure and creatinine.
  • Azathioprine 1 to 2.5 mg/kg per day, with thiopurine methyltransferase testing before starting.
  • Dupilumab (600 mg loading dose, then 300 mg subcutaneously every 2 weeks) when there is associated atopic dermatitis, and delgocitinib 2% cream for chronic hand eczema where available (evidence for this form of eczema is evolving).
  • Botulinum toxin injection for hyperhidrosis related disease has limited evidence.
• Secondary bacterial infection: flucloxacillin 500 mg orally 6 hourly for 7 days (clarithromycin 500 mg 12 hourly in penicillin allergy), or topical mupirocin 2% for localised disease. Treat tinea pedis with terbinafine 250 mg orally daily for 2 weeks, or topical terbinafine, to remove the id reaction trigger.
• Itch: a non-sedating antihistamine (cetirizine 10 mg at night) has limited value, and a sedating antihistamine (hydroxyzine 10 to 25 mg at night) may help sleep.
• Special groups:
  • Pregnancy: emollients, potent topical steroid for short periods, phototherapy with narrowband UVB, and prednisolone for severe flares. Avoid alitretinoin, methotrexate, and PUVA.
  • Children: weaker steroids for short periods (hydrocortisone 1%, or mometasone 0.1% for short courses), emollients, and tacrolimus 0.03%.
  • Renal impairment: avoid ciclosporin and reduce methotrexate dose.
  • Occupation: workplace changes, protective gloves, and occupational dermatology review for work related disease.
• Follow up: review at 2 to 4 weeks, then every 3 months. Refer to dermatology for failure of potent topical therapy, recurrent attacks, nail damage, need for patch testing, or systemic therapy.