- Physical Examination
- Surgical Examination
- Ophthalmology
- Clinical Skills
- Orthopedics
- Surgery Videos
- Laparoscopy
- Pediatrics
- Funny Videos
- Cardiothoracic Surgery
- Nursing Videos
- Plastic Surgery
- Otorhinolaryngology
- Histology and Histopathology
- Neurosurgery
- Dermatology
- Pediatric Surgery
- Urology
- Dentistry
- Oncology and Cancers
- Anatomy Videos
- Health and Fitness
- Radiology
- Anaesthesia
- Physical Therapy
- Pharmacology
- Interventional Radiology
- Cardiology
- Endocrinology
- Gynecology
- Emergency Medicine
- Psychiatry and Psychology
- Childbirth Videos
- General Medical Videos
- Nephrology
- Physiology
- Diet and Food Health
- Diabetes Mellitus
- Neurology
- Women Health
- Osteoporosis
- Gastroenterology
- Pulmonology
- Hematology
- Rheumatology
- Toxicology
- Nuclear Medicine
- Infectious Diseases
- Vascular Disease
- Reproductive Health
- Burns and Wound Healing
- Kidney Zone Podcast
- Other
L21.9 — Seborrheic dermatitis, unspecified
L21.9
What this code means
Seborrhoeic dermatitis causes scaly, flaky patches on the scalp (dandruff), face and chest, linked to skin yeasts.
Also called: seborrheic dermatitis, seborrhoeic dermatitis, dandruff.
When this code is used
Used for seborrhoeic dermatitis when the type is not specified.
Where it sits in ICD-10-CM
Code L21.9 belongs to Chapter 12: Diseases of the skin and subcutaneous tissue, which covers codes L00–L99 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.
Related symptoms
Related anatomy
Watch: related videos
Frequently asked questions
What is ICD-10-CM code L21.9?
L21.9 is the ICD-10-CM diagnosis code for “Seborrheic dermatitis, unspecified”. Seborrhoeic dermatitis causes scaly, flaky patches on the scalp (dandruff), face and chest, linked to skin yeasts.
When is code L21.9 used?
Used for seborrhoeic dermatitis when the type is not specified. It belongs to Chapter 12 of ICD-10-CM (Diseases of the skin and subcutaneous tissue).
This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.