L02.9

Cutaneous abscess, furuncle and carbuncle, unspecified

Cutaneous abscess, furuncle, and carbuncle represent a spectrum of localized skin infections characterized by inflammation and the accumulation of purulent material (pus). A cutaneous abscess is a localized collection of pus within the dermis or deeper skin tissues, often presenting as a fluctuant, erythematous, and painful nodule. A furuncle (commonly known as a boil) is a deep-seated infection involving a single hair follicle and the surrounding subcutaneous tissue. A carbuncle is a more extensive and deeper inflammatory mass composed of a cluster of interconnected furuncles, often involving multiple drainage sites and more significant systemic symptoms. These conditions are typically the result of bacterial invasion, most commonly by Staphylococcus aureus, and can occur on any part of the skin. This specific code, L02.9, is used when the clinician has identified one of these lesions but the specific anatomical location is not documented in the medical record, or when more specific sub-coding is required for billing (as L02.9 is a parent subcategory for further specific manifestations).

Clinical Symptoms

  • Localized pain and tenderness at the infection site
  • Swelling and induration (firmness) of the affected skin
  • Erythema (redness) surrounding the lesion
  • Localized warmth or heat
  • Fluctuance (the sensation of fluid movement under the skin)
  • Pustule formation or spontaneous drainage of purulent material
  • Fever and chills (more common in carbuncles or systemic spread)
  • Regional lymphadenopathy (swollen lymph nodes near the site)
  • General malaise or fatigue
  • Scarring or hyperpigmentation following resolution

Common Causes

  • Staphylococcus aureus (most common bacterial pathogen)
  • Methicillin-resistant Staphylococcus aureus (MRSA)
  • Streptococcus pyogenes (Group A Streptococcus)
  • Follicular occlusion or blockage of sweat glands
  • Minor skin trauma, abrasions, or lacerations providing entry for bacteria
  • Immunosuppression (e.g., HIV/AIDS, chemotherapy, organ transplant)
  • Chronic conditions such as diabetes mellitus
  • Poor hygiene practices
  • Close contact with individuals having active skin infections
  • Injection drug use

Documentation & Coding Tips

Specify the anatomical site to avoid using unspecified codes like L02.9.

Example: Patient presents with a 3cm cutaneous abscess on the right upper quadrant of the anterior abdominal wall. Site is localized to the trunk. Patient has a history of type 2 diabetes mellitus, currently controlled. Assessment: Cutaneous abscess of trunk (L02.211). Plan: Simple incision and drainage (10060).

Billing Focus: Anatomical site specificity and laterality for trunk or limb locations.

Differentiate between abscess, furuncle, and carbuncle based on clinical presentation.

Example: Physical exam reveals a cluster of several furuncles on the posterior neck forming a single inflammatory mass with multiple drainage points, diagnostic of a carbuncle. Patient also diagnosed with morbid obesity (BMI 42.5). Assessment: Carbuncle of the neck (L02.13).

Billing Focus: Clinical morphology (abscess vs. furuncle vs. carbuncle) determines the specific ICD-10 code.

Document the presence of any associated systemic inflammatory response or sepsis.

Example: Patient with cutaneous abscess of the left axilla presents with fever of 102.4F, tachycardia of 115 bpm, and leukocytosis. Blood cultures pending. Documented as sepsis due to Methicillin-resistant Staphylococcus aureus (MRSA) secondary to axillary cutaneous abscess. Assessment: A41.02, L02.415.

Billing Focus: Sequence the systemic infection (Sepsis) first if it meets criteria for the primary diagnosis.

Explicitly link the causative organism when identified via culture and sensitivity.

Example: Wound culture from the right thigh abscess confirmed Methicillin-susceptible Staphylococcus aureus. Patient is currently on a stable regimen for chronic obstructive pulmonary disease. Assessment: Cutaneous abscess of right lower limb (L02.413) and MSSA infection as the cause of diseases classified elsewhere (B95.61).

Billing Focus: The use of additional codes (B95-B97) to identify the infectious agent is required for complete coding.

Document if the abscess is a complication of a pre-existing condition such as diabetes or immunosuppression.

Example: Patient with Type 1 Diabetes Mellitus presents with a cutaneous abscess of the left foot. Abscess is not involving deeper structures but is slow-healing due to diabetic peripheral vascular disease. Assessment: Cutaneous abscess of left foot (L02.416), Type 1 DM with other skin complications (E10.628).

Billing Focus: Capturing the underlying manifestation (Diabetes with skin complication) ensures the clinical picture is accurately billed.

Clear documentation of the procedure performed, including complexity for I and D.

Example: Performed incision and drainage of a complex, multiloculated cutaneous abscess on the back. Required probing of loculations and placement of iodoform gauze packing. Procedure: Complicated I and D (10061). Assessment: Cutaneous abscess of the trunk (L02.211).

Billing Focus: Distinguishing between simple (10060) and complicated (10061) I and D based on documentation of packing, multiple incisions, or extensive probing.

Relevant CPT Codes