What L04 covers · when clinicians use it
ICD-10 code L04 identifies Acute lymphadenitis in the U.S. ICD-10-CM clinical and billing record set. It sits within the Skin & Subcutaneous Tissue chapter (L00–L99), the section that groups related diagnoses so providers, payers, and public-health agencies report them consistently. Clinicians and medical coders apply L04 when an encounter's findings match the Acute lymphadenitis description, attaching it to the patient record so downstream insurance claims, payer audits, quality reporting, and epidemiological surveillance all reference the same standardized diagnosis. The ICD-10-CM is maintained by the Centers for Medicare & Medicaid Services and the CDC's National Center for Health Statistics, with an updated official code set released each U.S. fiscal year — always verify L04 against the current CMS/CDC release and your payer's documentation guidance before final use. This page summarizes documentation context for L04 and is a coding reference, not clinical, diagnostic, or billing advice.
L04 refers to Acute lymphadenitis, a group of bacterial skin infections or inflammatory conditions that affect the skin, lymphatic tissue, or underlying subcutaneous areas. These conditions vary in severity from superficial infections like impetigo to deeper, more serious conditions like cellulitis or abscesses.
Symptoms
- Red, swollen, and painful skin – Common in cellulitis (L03) or abscesses (L02)
- Blistering or peeling – Characteristic of L00 (staphylococcal scalded skin)
- Crusting skin lesions – Seen in impetigo (L01)
- Painful lumps or drainage – Common with L02 and pilonidal cysts (L05)
- Fever and regional swelling – Indicate acute lymphadenitis (L04)
Diagnosis
Diagnosis of Acute lymphadenitis is clinical, based on physical examination. Pus culture, skin biopsy, ultrasound, and blood work may be needed to assess severity, rule out systemic infection, or confirm the bacterial organism responsible.
ICD10 Code Usage
ICD10 code L04 is used by dermatologists, infectious disease specialists, emergency physicians, and primary care providers. It supports coding for antibiotics, incision and drainage procedures, wound care, and surgical interventions in pilonidal disease.
Related Codes
- L00 – Staphylococcal scalded skin syndrome
- L01 – Impetigo
- L02 – Cutaneous abscess, furuncle and carbuncle
- L03 – Cellulitis and acute lymphangitis
- L05 – Pilonidal cyst and sinus
- L08 – Other local infections of skin and subcutaneous tissue
FAQs
Q1: What is ICD10 code L04?
A: It refers to Acute lymphadenitis, a skin or soft tissue infection requiring topical or systemic treatment.
Q2: What’s the difference between L02 and L03?
A: L02 refers to localized abscesses and boils, while L03 includes more diffuse infections like cellulitis that spread through tissue layers.
Q3: Is L00 a pediatric condition?
A: Mostly yes—staphylococcal scalded skin syndrome (L00) primarily affects infants and young children due to toxin-producing Staph aureus.
Q4: What are the risks of untreated L05?
A: Pilonidal cysts can become recurrent and lead to chronic infections or sinus tract formation requiring surgery.
Q5: Who treats these infections?
A: Dermatologists, general practitioners, ER doctors, and in some cases, general surgeons or wound care teams.
Conclusion
ICD10 code L04 ensures timely diagnosis and treatment of Acute lymphadenitis, improving outcomes for patients with skin and soft tissue infections through accurate medical documentation and management.