DISCUSSION
This condition is impetigo—in this case “non-bullous” impetigo, a rash that almost always begins with a breach in normal skin integrity. This opens the skin to superficial invasion by staph and strep organisms, mostly emitting from the nasal passages. In this case, the patient had been picking at seborrheic keratosis (an extremely common phenomenon in someone her age) on her face.
The inclination to scratch and pick—and the inability to manage nasal secretions—make children the most likely candidates for impetigo. It is especially common in those with atopic dermatitis, who not only have poor barrier function (which manifests as eczema) but also constant nasal drainage from seasonal allergies.
The differential includes herpes simplex or zoster, eczema and contact dermatitis. But the location of the rash, the honey-colored crust on an erythematous base, and the history of skin breaches all point directly to impetigo. Lymph nodes are often palpable in the drainage area; their presence corroborates the diagnosis.
Luckily, this type of impetigo is relatively easy to treat: The patient was advised to wash the area with soap and water and apply mupirocin ointment three times a day. She was also prescribed cephalexin (500 mg tid for a week), which cleared the condition aside from a faint bit of postinflammatory pinkness.
TAKE-HOME LEARNING POINTS
• Impetigo is a superficial bacterial infection, usually on or near the face, caused by staph and strep organisms that seed the area from the nasal passages.
• These organisms generally require a break in the skin to gain entrance, often caused by picking or scratching.
• Honey-colored crust on an erythematous base, plus or minus enlarged local nodes, help to confirm the diagnosis.
• Symptoms of impetigo include itching and mild discomfort but not pain.
• Treatment can be as simple as cleaning with soap and water and applying topical mupirocin ointment. A short course of oral antibiotics may be needed to speed the clearance process.