2025 ICD-10-CM Diagnosis Code R21
Rash and other nonspecific skin eruption
- ICD-10-CM Code:
- R21
- ICD-10 Code for:
- Rash and other nonspecific skin eruption
- Is Billable?
- Yes - Valid for Submission
- Chronic Condition Indicator: [1]
- Not chronic
- Code Navigator:
R21 is a billable diagnosis code used to specify a medical diagnosis of rash and other nonspecific skin eruption. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.
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.
Approximate Synonyms
The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.
- 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
- Acute pustular skin eruption
- Application site rash
- Application site reaction
- Bacteremic skin rash
- Bier anemic spots, cyanosis, and urticaria-like eruption syndrome
- Biers spots
- Blanching of skin
- Blanching rash
- Blisters beneath skin
- Broken skin
- Bullous eruption
- Butterfly rash
- Centrifugal rash
- Centripetal rash
- Disorder of skin co-occurrent with human immunodeficiency virus infection
- Disorder of skin co-occurrent with human immunodeficiency virus infection
- Disorder of skin due to human immunodeficiency virus infection
- Eruption
- Eruption of female perineum
- Eruption of skin caused by Salmonella
- Eruption of skin caused by Salmonella
- Eruption of skin caused by Salmonella
- Eruption of skin caused by Salmonella
- Eruption of skin caused by Salmonella Paratyphi
- Eruption of skin caused by Salmonella Paratyphi
- Eruption of skin caused by Salmonella Paratyphi
- Eruption of skin caused by Salmonella Paratyphi
- Eruption of skin caused by Salmonella Paratyphi A
- Eruption of skin caused by Salmonella Paratyphi B
- Eruption of skin caused by Salmonella Paratyphi C
- Eruption of skin co-occurrent with human immunodeficiency virus infection
- Eruption of skin of face
- Eruption of skin of penis
- Eruption of skin present
- Eruption of vulva
- Erythematous rash
- Exanthem caused by Chlamydophila psittaci
- Exanthem caused by human echovirus
- Exanthem caused by human echovirus 16
- Generalized rash
- Localized eruption of skin
- Macular eruption
- Maculopapular eruption
- Micropapular wheal
- Morbilliform eruption
- Multimorphic rash
- Non-blanching rash
- Ornithosis
- Orthostatic intolerance
- Papular eruption
- Papular eruption of blacks
- Papular pruritic eruption of skin due to human immunodeficiency virus infection
- Phototherapy skin rash
- Postural orthostatic tachycardia syndrome
- Premycotic eruption
- Rash due to dribbling from mouth
- Rash due to dribbling of urine
- Rash of genitalia
- Rash of groin
- Rash of periwound skin
- Rash of scalp
- Rash of systemic lupus erythematosus
- Rubelliform eruption
- Skin disorder with AIDS
- Skin rash with AIDS
- Southern tick-associated rash illness
- Synchronous rash
- Vaccination site rash
- Wheal
Clinical Classification
Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.
They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.
Skin/Subcutaneous signs and symptoms
CCSR Code: SYM014
Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.
Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Clinical Information
Postural Orthostatic Tachycardia Syndrome
a syndrome of orthostatic intolerance combined with excessive upright tachycardia, and usually without associated orthostatic hypotension. all variants have in common an excessively reduced venous return to the heart (central hypovolemia) while upright.Orthostatic Intolerance
symptoms of cerebral hypoperfusion or autonomic overaction which develop while the subject is standing, but are relieved on recumbency. types of this include neurocardiogenic syncope; postural orthostatic tachycardia syndrome; and neurogenic orthostatic hypotension. (from noseworthy, jh., neurological therapeutics principles and practice, 2007, p2575-2576)Ornithosis
disease caused by the chlamydophila psittaci bacteria, usually transmitted from birds to humans.
Tabular List of Diseases and Injuries
The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.
Includes
IncludesThis 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 ExcludesA 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 References
The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).
- - Eruption
- - skin (nonspecific) - R21
- - Rash (toxic) - R21
- - rose - R21
Convert R21 to ICD-9-CM
Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.
Nonspecif skin erupt NEC
ICD-9-CM: 782.1
This is a direct match with no additional mapping qualifiers. The absence of a flag generally means the mapping is considered exact or precise. In other words, the ICD-10 code maps cleanly to the ICD-9 code without qualification, approximation, or needing multiple codes.
Patient Education
Rashes
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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Code History
- FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
- FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
- FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
- FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
- FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
- FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
- FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
- FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
- FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.