Dyshidrotic Eczema (Pompholyx) Workup

Updated: Jun 20, 2022
  • Author: Sadegh Amini, MD; Chief Editor: William D James, MD  more...
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Approach Considerations

The diagnosis of dyshidrotic eczema is usually made clinically, although bacterial culture and sensitivity tests exclude secondary infection. Blood tests are not usually ordered; however, immunoglobulin E levels are commonly elevated.

Substances used to systemically challenge patients with possible ingested allergens may trigger exacerbations. Vasculitis or erythema multiforme may develop during this testing.

Use patch testing to exclude allergic contact dermatitis. Measuring thiopurine methyltransferase levels allows accurate dosing of azathioprine. Systemic evaluation is recommended in recalcitrant cases, including serology for human T-cell lymphotrophic virus type 1 (HTLV1), which can rule out dyshidrosis-like variant of adult T-cell leukemia/lymphoma. [31] Perform potassium hydroxide wet mount preparation to exclude dermatophyte infection.

Punch biopsy for hematoxylin and eosin staining usually is not necessary. Punch biopsy for periodic acid-Schiff staining may help to exclude dermatophytosis in patients with unresponsive disease. Use punch biopsy for direct immunofluorescence to exclude bullous pemphigoid.

Histologic findings

Spongiosis with an epidermal lymphocytic infiltrate and intraepidermal vesicles or bullae are present. The vesicles are not associated with sweat glands.