A 38-year-old woman presents to your urgent care clinic with a chief complaint of “infected foot.” She returned from Baja, Mexico, 2 days ago after spending a week-long vacation there. On her last day in Mexico, she was walking barefoot in the surf when a wave caused her to slip, fall, and strike her left foot on a rock. She didn’t seek medical attention immediately after the event because the bleeding was easily controlled and there was no gaping laceration. Since then, she has had increased redness and swelling over an abrasion/shallow laceration on her dorsolateral left foot. There has been no fever and there were no other injuries. She takes no medications and has no chronic medical problems. There are no known allergies and her tetanus vaccination was updated 3 years ago.
On examination, her vital signs are normal and she is afebrile. There is a 3 x 5 cm area of erythema, warmth, and tenderness surrounding a small abrasion over the dorsolateral metatarsal region of her left foot. No palpable fluid collection or fluctuance is appreciated, but there is a small amount of serosanguinous drainage over the abrasion. Pulses and capillary refill are excellent, and range of motion and sensation are intact. She can walk normally with no discomfort or limp. Which of the following courses of action would be best?
a. Order 3-view foot x-rays. If negative, discharge on cephalexin with wound care and primary care provider follow-up if needed.
b. Prescribe TMP/SMX to cover MRSA. Instruct patient to return for recheck in 2 days if not improved.
c. Prescribe cephalexin plus doxycycline. Discharge with instructions for local wound care and to follow up in 24 hours for recheck. Instruct the patient to report to the ED for any worsening redness, swelling, or fever in the meantime.
d. Thoroughly debride and irrigate the abrasion; after this, only topical antibiotics are necessary.
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Answer: C. Marine pathogens must be considered because the injury occurred while the patient was barefoot in the ocean. Vibrio is the most consequential of these, and doxycycline provides good coverage for it. Cephalexin provides the skin commensal coverage necessary to round out the treatment plan.