Infection of the lower leg not responding to antimicrobial therapy

Presenter: Shannon McKeen, DO

Dermatology Program: MSUCOM/Lakeland Regional Medical Center

Program Director: Mark A Kuriata, DO, FAOCD

Submitted on: October 31, 2015

CHIEF COMPLAINT: Infection on the left ankle

CLINICAL HISTORY: A 9-year-old female presented for evaluation of an infection on the left ankle. The patient injured her leg on a rock in Mobile Bay several months ago while on vacation with her family in Alabama. The wound was cultured and the patient was empirically started on Cephalexin by her primary care physician with little improvement. Wound culture from the outside office showed rare Staphylococcus epidermidis susceptible to Trimethoprim-Sulfamethoxazole. The patient is up to date on her Tetanus and other immunizations. No recent travel out of the country. The patient was started on Trimethoprim-Sulfamethoxazole and referred to Dermatology.

PHYSICAL EXAM:
Red-to-violaceous papulovesicles in a cluster and linear arrangement with mild surrounding erythema and overlying serous crust on the left lower leg

LABORATORY TESTS:

Tissue culture grew acid-fast bacilli which underwent species identification showing Mycobacterium marinum.

DERMATOHISTOPATHOLOGY:

Punch biopsy shows irregular epidermal acanthosis with associated infundibular epithelial hyperplasia. Throughout the superficial dermis, there is granulomatous histiocytic inflammation with associated lymphocytes and occasional plasma cells. PAS staining negative for fungal elements. Ziehl-Neelsen and Fite stain showing no acid-fast bacilli.