Furuncle of back [any part, except buttock and flank]

This code represents a localized, painful skin infection originating in a hair follicle, specifically located on the patient's back, excluding the buttock and flank regions. It is characterized by a central core of pus and necrotic tissue.

Use this code when documentation clearly indicates a diagnosis of a furuncle (boil) situated on the back. This diagnosis is typically supported by physical examination findings describing a tender, erythematous nodule with a pustular head.

• Ensure the documentation specifies the back as the anatomical site and explicitly rules out the buttock and flank.
• Do not confuse with carbuncle (L02.21-), which involves multiple hair follicles and forms a deeper, interconnected abscess.
• Consider an additional code for any associated cellulitis (L03.31-) if documented.