2026 ICD-10-CM Diagnosis Code J35.01

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.

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.

MS-DRG Mapping for ICD-10-CM Code J35.01

Diagnosis-Related Groups (DRGs) are used to classify hospital cases for billing and healthcare management. They help standardize how hospitals and other providers are reimbursed for inpatient care. Patients are grouped based on their principal diagnosis into broader categories called Major Diagnostic Categories (MDCs).

Once assigned to a DRG, the hospital receives a set payment for the patient’s care, regardless of the actual services provided. This fixed rate is intended to cover the typical cost of treating patients within that group. The payment amount depends on the DRG's relative weight, which reflects the expected complexity and cost of care based on the severity of the patient’s condition.

Diagnostic related groups encourage healthcare providers to focus on quality and efficiency in patient care while managing costs effectively. The diagnosis code is present in the following groups for version MS-DRG V43.0 applicable from 10/01/2025 through 09/30/2026.

Convert J35.01 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.

Patient Education

Tonsillitis

What are tonsils?

Tonsils are lumps of tissue at the back of the throat. There are two of them, one on each side. Along with the adenoids, tonsils are part of the lymphatic system. The lymphatic system clears away infection and keeps body fluids in balance. Tonsils and adenoids work by trapping the germs coming in through the mouth and nose.

What is tonsillitis?

Tonsillitis is an inflammation (swelling) of the tonsils. Sometimes along with tonsillitis, the adenoids are also swollen.

What causes tonsillitis?

The cause of tonsillitis is usually a viral infection. Bacterial infections such as strep throat can also cause tonsillitis.

Who is at risk for tonsillitis?

Tonsillitis is most common in children over age two. Almost every child in the United States gets it at least once. Tonsillitis caused by bacteria is more common in kids ages 5-15. Tonsillitis caused by a virus is more common in younger children.

Adults can get tonsillitis, but it is not very common.

Is tonsillitis contagious?

Although tonsillitis is not contagious, the viruses and bacteria that cause it are contagious. Frequent handwashing can help prevent spreading or catching the infections.

What are the symptoms of tonsillitis?

The symptoms of tonsillitis include:

• A sore throat, which may be severe
• Red, swollen tonsils
• Trouble swallowing
• A white or yellow coating on the tonsils
• Swollen glands in the neck
• Fever
• Bad breath

When does my child need to see a health care provider for tonsillitis?

You should call your health care provider if your child:

• Has a sore throat for more than two days
• Has trouble or pain when swallowing
• Feels very sick or very weak

You should get emergency care right away if your child:

• Has trouble breathing
• Starts drooling
• Has a lot of trouble swallowing

How is tonsillitis diagnosed?

To diagnose tonsillitis, your child's health care provider will first ask you about your child's symptoms and medical history. The provider will look at your child's throat and neck, checking for things such as redness or white spots on the tonsils and swollen lymph nodes.

Your child will probably also have one or more tests to check for strep throat, since it can cause tonsillitis and it requires treatment. It could be a rapid strep test, a throat culture, or both. For both tests, the provider uses a cotton swab to collect a sample of fluids from your child's tonsils and the back of the throat. With the rapid strep test, testing is done in the office, and you get the results within minutes. The throat culture is done in a lab, and it usually takes a few days to get the results. The throat culture is a more reliable test. So sometimes if the rapid strep test is negative (meaning that it does not show any strep bacteria), the provider will also do a throat culture just to make sure that your child does not have strep.

What are the treatments for tonsillitis?

Treatment for tonsillitis depends on the cause. If the cause is a virus, there is no medicine to treat it. If the cause is a bacterial infection, such as strep throat, your child will need to take antibiotics. It is important for your child to finish the antibiotics even if he or she feels better. If treatment stops too soon, some bacteria may survive and re-infect your child.

No matter what is causing the tonsillitis, there are some things you can do to help your child feel better. Make sure that your child:

• Gets a lot of rest
• Drinks plenty of fluids
• Tries eating soft foods if it hurts to swallow
• Tries eating warm liquids or cold foods like popsicles to soothe the throat
• Isn't around cigarette smoke or anything else that could irritate the throat
• Sleeps in a room with a humidifier
• Gargles with saltwater
• Sucks on a lozenge (but do not give them to children under four; they can choke on them)
• Takes an over-the-counter pain reliever such as acetaminophen. Children and teenagers should not take aspirin.

In some cases, your child may need a tonsillectomy.

What is a tonsillectomy and why might my child need one?

A tonsillectomy is surgery to remove the tonsils. Your child might need it if he or she:

• Keeps getting tonsillitis
• Has bacterial tonsillitis that does not get better with antibiotics
• Has tonsils that are too big and are causing trouble breathing or swallowing

Your child usually gets the surgery and goes home later that day. Very young children and people who have complications may need to stay in the hospital overnight. It can take a week or two before your child completely recovers from the surgery.

[Learn More in MedlinePlus]

Code History

• FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
• FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
• 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.