History
A 27-year-old man attends your clinic with a 3-day history of a severe burning itch over his hands associated with localized blistering and similar although less severe changes on his feet. He is otherwise well, although he did suffer from asthma is childhood and occasionally still experiences hay fever. He is on no medication. He works as a graphic designer and his hobbies include cycling and football, he has no exposure to allergens or irritants. He is unaware of any triggering factor.
Examination
He has diffuse vesicles, coalescing to form tense bullae over the palmar aspects of both hands extending into the interdigital spaces (Fig. 5.1) and onto the dorsa of his fingers and hand. In addition he has erythema, maceration, fissuring and peeling between the 4th and 5th toes on the left side and bilateral but asymmetrical (left worse than right) purulent vesicles over the insteps.
Questions
• What is the diagnosis?
• What investigations would you perform?
• What treatments would you initiate?
Medicine
The diagnosis is pompholyx or dyshidrotic eczema, the symmetrical and diffuse clear ves-icles over the palmar aspect of the hands associated with pruritus are highly suggestive and the diagnosis is based on clinical features. Other differential diagnoses to consider include contact dermatitis (irritant or allergic), friction blisters (e.g. epidermolysis bullosa simplex), herpes simplex infection, and palmoplantar pustular psoriasis. Atopy appears to be a predisposing factor for pompholyx. There are several potential triggers of pompholyx including stress and as an ‘id reaction’ to a distant dermatophyte infection. In this case the features of interdigital maceration associated with inflamma-tory pustules and vesicles on the instep are suggestive of inflammatory tinea pedis. Investigations should include scrapings from the feet (interdigital spaces and affected areas over the plantar aspects) and hands for mycological tests (direct microscopy and culture). In this case, scrapings from the feet demonstrated hyphae and spores on direct microscopy with subsequent culture confirming the presence of the zoophilic organism Trichophyton mentagrophytes var. mentagrophytes. There was no fungal infection of the hands. Treatment of a pompholyx ‘id reaction’ involves treatment of the tinea pedis as well as treatment of the pompholyx itself. Inflammatory tinea pedis is usually managed with sys-temic antifungal therapy (itraconzole, terbinafine or fluconazole). Infected scales can be present on clothing or within footwear, so frequent laundering is recommended. Draining the larger bullae with a sterile needle will reduce the discomfort. Compresses or soaks with dilute potassium permanganate help to dry the vesicles and prevent secondary bac-terial infection. Potent or superpotent topical corticosteroids are the mainstay of therapy. In the short term a combination preparation of topical corticosteroids and antibacterial agent is useful. Occasionally, systemic steroids are required.
KEY POINTS
• Pompholyx occurs as a manifestation of hand eczema, irritant or allergic dermatitis and as an ‘id reaction’ to a distant dermatophyte infection.
• The mainstay of treatment is the prevention of secondary infection and use of potent or superpotent topical corticosteroids as well as identification and eradication of the trigger.
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