11900

Injection, intralesional; up to and including 7 lesions

Current Procedural Terminology (CPT) code 11900 designates the therapeutic intralesional injection of medicinal agents into one to seven localized skin lesions. This procedure involves the direct delivery of a pharmacological agent, most commonly a corticosteroid such as triamcinolone acetonide, into the dermal or subcutaneous tissue of a specific lesion rather than into the systemic circulation. By depositing the medication directly into the pathological site, the physician maximizes the local therapeutic concentration and efficacy of the drug while minimizing systemic absorption and potential adverse side effects. Intralesional injections are a cornerstone of dermatological therapy, frequently utilized to manage a wide array of inflammatory, hyperplastic, and cystic cutaneous disorders. Common clinical indications include the treatment of keloids and hypertrophic scars, where the corticosteroid acts to reduce collagen synthesis and decrease fibroblast proliferation, thereby flattening the scar and alleviating associated pruritus or pain. Additionally, this procedure is highly effective for localized inflammatory conditions such as severe nodulocystic acne, hidradenitis suppurativa, prurigo nodularis, localized plaque psoriasis, and granuloma annulare. In cases of alopecia areata, intralesional corticosteroids suppress the localized autoimmune attack on hair follicles, promoting hair regrowth. The procedure requires careful technique; the physician typically uses a fine-gauge needle (e.g., 27-gauge or 30-gauge) attached to a small-volume syringe to inject a precise amount of medication until the lesion mildly blanches or becomes palpably indurated. The dosage and concentration of the medication depend strictly on the nature, size, and anatomical location of the lesion to prevent local complications such as cutaneous atrophy, telangiectasia, or hypopigmentation. CPT code 11900 specifically encompasses the procedural work required to inject up to and including seven distinct lesions during a single patient encounter. The number of injections per lesion or the total volume of medication administered does not alter the code selection; the code is strictly defined by the total number of distinct lesions treated. When performing this procedure, practitioners must also document the specific medication, dosage, and volume administered to appropriately report the corresponding Healthcare Common Procedure Coding System (HCPCS) J-codes for drug reimbursement.

Clinical Indications

  • Keloids and hypertrophic scars
  • Nodulocystic acne
  • Alopecia areata
  • Psoriasis (localized plaques)
  • Hidradenitis suppurativa
  • Prurigo nodularis
  • Granuloma annulare
  • Lichen planus
  • Discoid lupus erythematosus

Procedure Steps

  1. Verify patient consent and confirm the identity, location, and number of lesions to be treated.
  2. Cleanse the skin overlying the target lesions with an appropriate antiseptic solution such as alcohol or chlorhexidine.
  3. Prepare the medication, typically a corticosteroid like triamcinolone acetonide, drawing it into a small-volume syringe (e.g., tuberculin syringe).
  4. Mix the medication with a local anesthetic such as lidocaine if clinically indicated to reduce injection pain.
  5. Insert a fine-gauge needle (usually 27 to 30-gauge) directly into the dermal or subcutaneous layer of the target lesion.
  6. Slowly inject the medication into the lesion until slight tissue blanching or palpable induration is observed.
  7. Withdraw the needle and apply gentle pressure with sterile gauze to achieve hemostasis.
  8. Repeat the injection process for additional distinct lesions, ensuring the total number of lesions treated is seven or fewer.
  9. Apply an adhesive bandage or light dressing over the injection sites if necessary.
  10. Provide the patient with post-procedural care instructions, including signs of infection or potential side effects like hypopigmentation or atrophy.

Coding Guidelines

  • Report CPT code 11900 when injecting anywhere from one to seven distinct lesions.
  • Do not report CPT code 11900 in conjunction with CPT code 11901 (more than 7 lesions) during the same encounter; they are mutually exclusive.
  • The code selection is based entirely on the number of lesions injected, not on the number of injections performed per lesion or the total volume of medication administered.
  • The pharmacological agent injected is not included in the procedure code and should be reported separately using the appropriate HCPCS Level II J-code (e.g., J3301 for triamcinolone acetonide).
  • Do not use 11900 for typical subcutaneous or intramuscular therapeutic injections; use CPT 96372 instead.
  • Do not report this code for allergy testing or immunotherapy injections.
  • If a significant, separately identifiable Evaluation and Management (E/M) service is performed on the same day, report the appropriate E/M code appended with modifier 25.

Associated ICD-10 Codes