Case Reports

Bullous Eruption Caused by an Exotic Hedgehog Purchased as a Household Pet

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An unusual case of a 37-year-old woman with bullous tinea manuum caused by an infection with Trichophyton mentagrophytes is described. The patient presented with a pruritic erythematous vesicular rash on the right palm and interdigital web spaces between the first and second digits. The preliminary diagnosis was acute contact dermatitis, which was treated with oral and topical corticosteroids. The rash failed to respond to treatment, resulting in tinea incognito. At 2-week follow-up, a potassium hydroxide (KOH) preparation performed in clinic was positive for T mentagrophytes. The suspected source of infection was a domestic 4-toed, white-bellied African pygmy hedgehog (Atelerix albiventris). There was remarkable improvement of the lesion after 2 weeks with appropriate topical and systemic antifungal agents. This case illustrates that popular exotic pets such as the hedgehog can increase the risk for zoophilic dermatophytic infection, which can present as bullous lesions with little or no scale and can be confused with acute contact dermatitis. It is important for the clinician to recognize this presentation and provide close follow-up for lesions not responding to treatment.

Practice Points

  • Bullous tinea may present with little or no scale, which can lead to confusion with acute contact dermatitis.
  • The recent popularity of exotic pets may increase the incidence of fungal zoonotic dermatitis.
  • Prompt recognition of tinea incognito is essential when treating lesions with corticosteroids.
  • Skin lesions not responding appropriately to therapy warrant reassessment and further evaluation.


 

References

Case Report

A 37-year-old woman presented to the dermatology clinic with an itchy rash involving the right hand. The rash had been present for 10 days but had become increasingly pruritic and vesicular over the last 5 days. She denied new exposures or other household members with similar symptoms. The patient reported that she had purchased a 4-toed, white-bellied African pygmy hedgehog (Atelerix albiventris) approximately 4 months prior. Upon questioning, she stated that she handled the hedgehog a couple of times a week and always washed her hands with soap and water immediately after. The patient’s medical and personal history were otherwise unremarkable.

Review of systems, including fevers, chills, and night sweats, was negative. Clinical examination revealed erythema with overlying vesicles and pustules on the right radial palm, radial dorsal hand, and interdigital web space of the first and second digit (Figure 1). The eruption was actively discharging serous exudate. No other lesions were present.

Figure 1. Erythematous vesiculobullous plaque on the right palm, interdigital web spaces, and radial aspect of first digit, with pustules and actively discharging serous exudate.

Unspecified acute contact dermatitis was the preliminary diagnosis based on clinical presentation and history. Other entities considered before making the diagnosis included psoriasis, eczema, and an infectious cause. Specimens were taken for bacterial and fungal cultures as well as a specimen for herpes simplex virus by polymerase chain reaction. Due to the intense pruritus and vesicular nature of the rash, the patient was treatedwith a 2-week, 60-40-20 prednisone taper and clobetasol propionate ointment 0.05% twice daily.

At 1-week follow-up, the eruption had improved, but the patient was still experiencing mild pruritus. Physical examination of the affected areas showed erythematous, violaceous, annular patches with slight scale at the periphery; all bullous lesions had resolved (Figure 2). Bacterial culture and herpes simplex virus by polymerase chain reaction were negative.

Figure 2. After 1 week of therapy with prednisone and clobetasol propionate ointment 0.05%, the eruption had improved, but there was an annular violaceous patch on the right radial palm with a few erosions at the periphery of the lesion.

Two weeks after initial consultation, the fungal culture returned positive and showed growth of Trichophyton mentagrophytes. The patient was contacted and returned for re-evaluation. Physical examination showed decreased erythema and no bullous lesions; however, there was increased fine scale throughout the affected area on the right palm and first and second interdigital spaces (Figure 3). She reported mild pruritus. A confirmatory potassium hydroxide (KOH) preparation was positive for fungal hyphae. The patient was subsequently diagnosed with bullous tinea secondary to domestic hedgehog exposure that was now presenting as tinea manuum incognita. After 2 weeks of appropriate systemic and topical antifungal therapy, the patient’s skin eruption markedly improved (Figure 4).

Figure 3. After 2 weeks of therapy, there was an erythematous patch with overlying fine scale.

Figure 4. After 2 weeks of systemic and topical antifungal therapy (4 weeks after initial presentation), the fungal infection was resolving, with decreased scale, erosions, and annular configuration.

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