ICD-10-CM Code R21

Rash and other nonspecific skin eruption

Version 2020 Billable Code No Valid Principal Dx

Valid for Submission

R21 is a billable code used to specify a medical diagnosis of rash and other nonspecific skin eruption. The code is valid for the year 2020 for the submission of HIPAA-covered transactions. The ICD-10-CM code R21 might also be used to specify conditions or terms like acute blistering eruption of skin, acute desquamating eruption of skin, acute discoid eruption of skin, acute eruption of skin, acute erythematous eruption of skin, acute exudative skin eruption, etc

According to ICD-10-CM guidelines this code should not to be used as a principal diagnosis code when a related definitive diagnosis has been established.

Short Description:Rash and other nonspecific skin eruption
Long Description:Rash and other nonspecific skin eruption

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code R21:


This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
  • rash NOS

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • specified type of rash- code to condition
  • vesicular eruption R23.8

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code R21 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Acute blistering eruption of skin
  • Acute desquamating eruption of skin
  • Acute discoid eruption of skin
  • Acute eruption of skin
  • Acute erythematous eruption of skin
  • Acute exudative skin eruption
  • Acute maculopapular eruption of skin
  • Acute papular eruption of skin
  • Application site rash
  • Blanching rash
  • Blisters beneath skin
  • Broken skin
  • Butterfly rash
  • C/O: a rash
  • Centrifugal rash
  • Centripetal rash
  • Disorder of skin co-occurrent with human immunodeficiency virus infection
  • Eruption
  • Eruption of female perineum
  • Eruption of skin co-occurrent with human immunodeficiency virus infection
  • Eruption of vulva
  • Exanthem caused by Chlamydophila psittaci
  • Generalized rash
  • Irritation symptom
  • Localized eruption of skin
  • Macular eruption
  • Maculopapular eruption
  • Micropapular weal
  • Morbilliform eruption
  • Multimorphic rash
  • Non-blanching rash
  • O/E - discoid rash
  • O/E - dribble rash
  • O/E - itchy rash
  • O/E - macules
  • O/E - macules present
  • O/E - rash present
  • O/E - scalp rash
  • O/E - weals present
  • Ornithosis
  • Papular eruption
  • Papular eruption of blacks
  • Phototherapy skin rash
  • Premycotic eruption
  • Rash of genitalia
  • Rash of groin
  • Rash of periwound skin
  • Rash of systemic lupus erythematosus
  • Rubelliform eruption
  • Skin disorder associated with AIDS
  • Skin rash associated with AIDS
  • Skin symptom
  • Southern tick-associated rash illness
  • Symptom of skin and integumentary tissue
  • Synchronous rash
  • Weal
  • Weal

Diagnostic Related Groups

The ICD-10 code R21 is grouped in the following groups for version MS-DRG V37.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2019 through 09/30/2020.


Convert R21 to ICD-9

  • 782.1 - Nonspecif skin erupt NEC

Code Classification

  • Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00–R99)
    • Symptoms and signs involving the skin and subcutaneous tissue (R20-R23)
      • Rash and other nonspecific skin eruption (R21)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Patients


A rash is an area of irritated or swollen skin. Many rashes are itchy, red, painful, and irritated. Some rashes can also lead to blisters or patches of raw skin. Rashes are a symptom of many different medical problems. Other causes include irritating substances and allergies. Certain genes can make people more likely to get rashes.

Contact dermatitis is a common type of rash. It causes redness, itching, and sometimes small bumps. You get the rash where you have touched an irritant, such as a chemical, or something you are allergic to, like poison ivy.

Some rashes develop right away. Others form over several days. Although most rashes clear up fairly quickly, others are long-lasting and need long-term treatment.

Because rashes can be caused by many different things, it's important to figure out what kind you have before you treat it. If it is a bad rash, if it does not go away, or if you have other symptoms, you should see your health care provider. Treatments may include moisturizers, lotions, baths, cortisone creams that relieve swelling, and antihistamines, which relieve itching.

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