Bullous Pemphigoid Masquerading as Recurrent Vesicular Hand Eczema
Lupi et al. present, on p. 80–81, an interesting case report of dyshidrosiform palmo-plantar pemphigoid. They describe a 20-year-old man who had had itchy vesicles on his palms and soles for 1 year. Histologically, a subepidermal vesicle was seen, and direct immunofluorescence showed continuous linear deposition of IgG and C3 at the dermal-epidermal junction. An enzyme-linked immunosorbent assay (ELISA) for circulating antibodies against bullous pemphigoid antigen BP 180 was positive.
Based on the figures in their report, the current case was, morphologically, classical recurrent vesicular hand eczema. However, the features that distinguish the current case from recurrent vesicular hand eczema (dyshidrotic eczema or pompholyx) are: (i) that histopathology showed a subepidermal vesicle, while recurrent vesicular hand eczema shows spongiosis and intraepidermal vesicles; (ii) that direct immunofluorescence showed linear deposition of IgG and C3 along the dermal-epidermal junction; and (iii) no improvement was seen after 16 weeks of therapy with 25 mg prednisone daily. Recurrent vesicular hand eczema usually responds well to this treatment.
The terms dyshidrosis, pompholyx and acute and recurrent vesicular hand eczema have been used interchangeably to describe eruptions of tiny vesicles with sparse or no inflammation on the palms and sometimes also on the soles. If vesicles coalesce they may form bullae.
The term dyshidrosis or dyshidrosiform is best avoided. It has been shown repeatedly that there is no connection between the vesicles and the acrosyringium in vesicular hand dermatitis.
The term pompholyx is best reserved for the rare, sudden, severe, self-healing vesicular and/or bullous eruptions on the palms and, occasionally also, on the soles with no or sparse inflammation (1, 2). Indeed, the term “pompholyx” could be replaced by “acute vesicular hand eczema”. The aetiology of this condition is unknown.
Recurrent vesicular hand dermatitis is probably the best term to describe the more common, milder vesicular eruptions on the palms with sharp delineation to palmar skin and with no or moderate inflammation. A multitude of aetiologies have been linked to this eczematous eruption, including allergic and irritant contact dermatitis, systemic contact dermatitis and dermatophytid.
It is probably useful to consider recurrent vesicular hand dermatitis to be a characteristic but non-specific reaction pattern of palmar and plantar skin with many possible causes (3). Thus the title of the current case report could have been “Bullous pemphigoid masquerading as recurrent vesicular hand dermatitis”.
Niels K Veien, MD, PhD
DK-9000 Aalborg, Denmark