Pruritic, painful callus on the toe

Presenter: Ashley Feneran, D.O., Sital Patel, D.O., Kevin Cooper, M.D.
Dermatology Program: University Hospitals Richmond Medical Center
Program Director: Jenifer Lloyd, D.O.
Submitted on: Mar 3, 2014

CHIEF COMPLAINT:  40 year-old Caucasian female with no significant past medical history who presents with new onset callus on the left third toe.

CLINICAL HISTORY:

Signs and symptoms:  Initially, patient complained of pruritus and pain at the site which worsened over time. Eventually the site drained purulent exudate.

Previous Treatment:  Three 7-day courses of levofloxacin 500mg daily prior to presenting to dermatology.

Other information:  Prior to development of the lesion, the patient admits to travel to Kenya to perform in rural outreach projects. A bone scan was negative for osteomyelitis.

 

PHYSICAL EXAM:

Examination revealed a well-appearing female with a pearl-like whitish papule with a central black dot (Figure 1). Several weeks later, the area was ulcerated with purulent exudate (Figure 2).

 

Figure 1. A pearl-like whitish papule with a central black dot

 

Figure 2. The area was ulcerated with purulent exudate

LABORATORY TESTS:

None.

DERMATOHISTOPATHOLOGY:

Microscopic examination of a shave biopsy of the left third toe reveals parakeratosis with basophilic material in addition to eosinophilic ribbons. There are also circular structures throughout.

 

Figure 3. Left third toe shave biopsy (H&E, 4x)

 

Figure 4. Left third toe shave biopsy (H&E, 10x)

DIFFERENTIAL DIAGNOSIS:

1.   Localized cutaneous leishmaniasis
2.   Myiasis
3.   Tungiasis
4.   Foreign body
5.   Cercarial dermatitis


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