Dermatologic Diseases

DERMATOLOGIC DISEASES

CASE 1: Cellulitis

Setting: ED

CC: “My leg hurts.”

VS: BP, 121/86 mm Hg; R, 18 breaths/min; P, 89 beats/min; T, 100.9°F

HPI: A 32-year-old man presents to the emergency department 3 days after being in India for 1 week. He had several mosquito bites and now has pain over the anterior part of his right leg. He had some fevers at home as well.

ROS:

• Fever

• Chills

• Leg pain

Physical Exam:

• An erythematous, warm, tender, 2-cm, fluctuant wound is seen over the anterior tibia of the right leg (Figure 15-1).

Figure 15-1. Cellulitis. Cellulitis of the left leg characterized by erythema and mild swelling. (Reproduced, with permission, from Knoop KJ, Stack LB, Storrow AB, Thurman R, eds. The Atlas of Emergency Medicine. 3rd ed. New York: McGraw-Hill; 2010. Photo contributor Frank Birinyi, MD.)

• There is serosanguineous drainage when the leg is pressed followed by purulent material that can easily be expressed from beneath the wound (Figure 15-2).

Figure 15-2. Cellulitis. Erythema consistent with cellulitis of the right lower extremity. (Reproduced, with permission, from Knoop KJ, Stack LB, Storrow AB, Thurman R, eds. The Atlas of Emergency Medicine. 3rd ed. New York: McGraw-Hill; 2010. Photo contributor: Lawrence B. Stack, MD.)

What is the most likely diagnosis?

a. Erysipelas

b. Complicated cellulitis

c. Necrotizing fasciitis

d. Pyoderma gangrenosum

e. Lymphangitis

Answer b. Complicated cellulitis

Cellulitis is nonnecrotizing inflammation of the skin and subcutaneous tissues of the skin. It occurs because of a breach in the skin, which commonly can occur from self-inoculation with bacteria. Common breaches of the skin are puncture wounds, cuts, and insect bites. Erysipelas is an infection of the subcutaneous fat, and necrotizing fasciitis presents with a skin infection with severe pain out of proportion to examination findings. Pyoderma gangrenosum is seen commonly in patients with inflammatory bowel disease. Lymphangitis is an infection of the lymphatics caused by streptococcal species.

Staphylococcus aureus creates a yellowish gold pigment.

S. aureus has coagulase in its cell surface.

Coagulase “melts” into tissues to damage them.

The five skin infections caused by streptococcal species are LINES:

Lymphangitis

Impetigo

Necrotizing fasciitis

Erysipelas

Scarlet fever

What is the best next step in the management of this patient?

a. Incision and drainage

b. Antibiotics

c. Surgical consult

d. All of the above

Answer d. All of the above

With a patient who presents with complicated cellulitis, also known as an abscess, the management involves incision and drainage by surgery to treat the underlying process. This is followed by starting targeted antibiotics that will treat the most common organisms and supportive care such as antipyretics.

Orders:

• Trimethoprim–sulfamethoxazole

• Surgical consult

• Incision and drainage

The most common organism to cause cellulitis is S. aureus (methicillin-resistant S. aureus [MRSA] and methicillin-susceptible S. aureus [MSSA])

Oral antibiotics that cover MRSA and MSSA are:

• Clindamycin

• Doxycycline

• Trimethoprim–sulfamethoxazole

The patient undergoes an incision and drainage and is given antibiotics. A total of 7 cc of purulence is expressed from the lesion on his leg, and it is bandaged.

Ceftaroline is the only cephalosporin that covers MRSA.

Order:

• Change the patient’s location to home

The patient returns to the emergency department 2 days later and says his wound is improving but is still red and painful. The culture from the incision and drainage grows 10,000 colonies of MRSA.

Orders:

• Vancomycin

• Admit to the hospital

Turn the clock forward, and the case will end.

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