Skin and soft tissue infections: Clinical

Focal skin and soft tissue infections are often due to bacteria infections, and include conditions like impetigo, folliculitis, cellulitis, erysipelas, furuncles and carbuncles, and necrotizing fasciitis.

The first step is getting a full history.

In impetigo, there’s usually no pain, whereas in necrotizing fasciitis the pain is severe.

Most skin infections tend to be localized and around a particular anatomic structure.

For example, folliculitis, furuncles, and carbuncles involve the hair follicle.

Also, a superficial infection like impetigo or folliculitis causes itchiness.

In erysipelas, the fever is high and abrupt in onset, and in necrotizing fasciitis the fever usually persists.

Some individuals have had contact with other individuals with skin infections, and this is commonly the case with community-acquired methicillin-resistant S. aureus, which causes cellulitis and furuncles.

On physical exam, there may be signs of systemic illness like fever and chills, and signs of toxicity like lethargy, tachycardia, and hypotension.

Additionally, there may be adenopathy, which can occur in non-bullous impetigo and cellulitis, bullae which can be seen in bullous impetigo, and crepitus with edema that exceeds the rash border, which can be seen in necrotizing fasciitis.

The rash may be papular as in folliculitis, vesicular or pustular like in impetigo, or there may be macular erythema like in cellulitis.

Additional labwork should be done when there are signs and symptoms of systemic toxicity.

A Gram’s stain, skin and swab cultures can help identify a specific pathogen like community-acquired methicillin-resistant S. aureus.

Blood cultures are unlikely to be positive in simple localized infections like impetigo and folliculitis, but should be taken when there’s deep tissue involvement like necrotizing fasciitis or erysipelas.