Rheumatic fever classification

Template:Acute rheumatic fever Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Monish Thuvooru Muthu Kalyanaraman, M.B.B.S[2]

Classification

Overview

This section covers the diagnostic classification framework for acute rheumatic fever (ARF), centered on the 2015 AHA Revised Jones Criteria — the current standard for ARF diagnosis. It details the population-stratified diagnostic thresholds (low-risk vs. moderate/high-risk), the distinction between initial and recurrent ARF, the concept of "possible" ARF, the role of subclinical carditis, evidence of preceding Group A Streptococcus (GAS) infection, and the broader disease spectrum taxonomy from ARF through chronic rheumatic heart disease (RHD). Clinical descriptions of individual manifestations, echocardiographic technique, laboratory workup, and treatment are covered in their respective microchapters.

2015 AHA Revised Jones Criteria: The Current Diagnostic Standard

The Jones Criteria, originally developed in 1944, underwent their most significant revision in 2015 by the American Heart Association (AHA) to address two key limitations of prior versions: (1) the failure of a single set of criteria to serve populations with vastly different disease burdens, and (2) the exclusion of echocardiography-detected (subclinical) carditis. The 2015 revision introduced population-stratified diagnostic thresholds, with more lenient criteria for moderate/high-risk populations (prioritizing sensitivity) and more stringent criteria for low-risk populations (prioritizing specificity).

Defining Population Risk

• Low-risk populations: ARF incidence <2 per 100,000 school-aged children (5–14 years) per year, or all-age RHD prevalence ≤1 per 1,000 population per year (e.g., most of North America, Western Europe, Japan).
• Moderate/high-risk populations: ARF incidence ≥2 per 100,000 school-aged children per year, or all-age RHD prevalence >1 per 1,000 population per year (e.g., sub-Saharan Africa, South Asia, Oceania, Indigenous populations of Australia/New Zealand).

When population risk status is uncertain, clinicians should apply the moderate/high-risk criteria to minimize the risk of missed diagnoses. Of note, Dougherty et al. (JACC 2023) define moderate/high-risk populations using >2 per 100,000 (strictly greater than), whereas Gewitz et al. (AHA 2015) and Hirani et al. (Lancet 2025) use ≥2 per 100,000. This distinction is rarely consequential in practice.

Diagnostic Requirements

All diagnoses require evidence of preceding GAS infection, with two exceptions: Sydenham chorea and indolent (insidious-onset) carditis may stand alone without documented GAS evidence, because of the long latency period of chorea (months) and the potential for streptococcal markers to have normalized by the time of presentation.

• Initial ARF: 2 major manifestations, OR 1 major + 2 minor manifestations.
• Recurrent ARF (in a patient with a prior documented ARF episode): 2 major, OR 1 major + 2 minor, OR 3 minor manifestations.

Major and Minor Criteria by Population Risk

Criterion Category	Low-Risk Populations	Moderate/High-Risk Populations
Major: Carditis	Clinical and/or subclinical (echocardiographic)	Clinical and/or subclinical (echocardiographic)
Major: Arthritis	Polyarthritis only	Monoarthritis or polyarthritis; polyarthralgia‡
Major: Chorea	Yes	Yes
Major: Erythema marginatum	Yes	Yes
Major: Subcutaneous nodules	Yes	Yes
Minor: Joint	Polyarthralgia	Monoarthralgia
Minor: Fever	≥38.5°C	≥38°C
Minor: Inflammatory markers	ESR ≥60 mm/h and/or CRP ≥3.0 mg/dL	ESR ≥30 mm/h and/or CRP ≥3.0 mg/dL
Minor: PR interval	Prolonged (age-adjusted), unless carditis is a major criterion	Prolonged (age-adjusted), unless carditis is a major criterion

‡Polyarthralgia should only be considered as a major manifestation in moderate-risk to high-risk populations after exclusion of other causes.

Key rule: Joint manifestations can be counted in either the major or minor category, but not both simultaneously in the same patient.

Subclinical Carditis as a Major Criterion

A landmark change in the 2015 revision was the formal inclusion of subclinical carditis (echocardiographic valvulitis without auscultatory findings) as fulfilling the major criterion of carditis. Pathological mitral or aortic regurgitation detected by echocardiography is now diagnostic of carditis regardless of the presence or absence of a murmur. Isolated pericarditis or myocarditis should almost never be considered rheumatic in origin; valvulitis is the most consistent cardiac feature of ARF. Detailed Doppler criteria (jet length, velocity, and duration thresholds) are covered in the Echocardiography microchapter.

Subclinical carditis is estimated to occur in approximately 12–21% of ARF cases. A study from Sudan showed that up to 11% of febrile children had subclinical carditis as their only major manifestation of ARF, underscoring the need for echocardiography in all suspected ARF cases.

Evidence of Preceding GAS Infection

One of the following must be documented to satisfy this requirement:

• Positive throat culture or rapid antigen detection test (RADT) for GAS
• Elevated or rising streptococcal antibody titers (ASO, anti-DNase B)
• Recent documented scarlet fever (listed in the AHA statement but rarely the sole means of documentation in practice)

Providing evidence of antecedent GAS infection remains an ongoing challenge, particularly in endemic settings where background seropositivity is high and skin infection (impetigo) may also trigger ARF.

"Possible" ARF Category

Patients who do not fully meet the Jones Criteria but have a clinical presentation highly suggestive of ARF may be classified as "possible ARF", particularly in moderate/high-risk populations. This category is clinically important because it may warrant initiation of secondary prophylaxis pending further evaluation. However, the non-specific nature of some minor features (arthralgia, elevated ESR) within this category carries a risk of misdiagnosis, unnecessary prophylaxis, and patient anxiety.

Classification of Recurrent ARF

Recurrent episodes carry a higher risk of progressive valvular damage and RHD. The 2015 criteria use a lower diagnostic threshold for recurrent ARF: 3 minor manifestations alone (with evidence of GAS infection) can satisfy criteria in a patient with a documented prior ARF episode. This is a key distinction from the initial episode, which always requires at least one major manifestation.

Disease Spectrum Taxonomy: ARF to RHD

ARF and RHD represent a continuum of disease rather than discrete entities. The following taxonomy, based on the JACC 2023 framework, classifies the spectrum according to detection method (clinical vs. echocardiographic) and timing:

• ARF with clinical carditis: Valvulitis detected by auscultation during an acute ARF episode
• ARF with subclinical carditis: Valvulitis detected only on echocardiography during an acute ARF episode
• Clinical RHD: Chronic valvular disease detected when symptomatic patients present to care
• Subclinical/latent RHD: Chronic valvular lesions detected by echocardiographic screening in asymptomatic individuals with no known ARF history

The original WHF echocardiographic criteria were published by Reményi et al. (Nat Rev Cardiol, 2012) and are reproduced in Watkins et al. (JACC, 2018). The 2012 WHF guidelines (updated in 2023) introduced a classification for definite RHD with categories A–D based on valve pathology pattern. For individuals aged ≤20 years: (A) pathological MR with ≥2 morphological features of RHD of the MV, (B) MS with mean gradient ≥4 mmHg, (C) pathological AR with ≥2 morphological features of RHD of the AV, and (D) borderline disease of both the AV and MV. For individuals aged >20 years: Categories A and B are the same; (C) pathological AR with ≥2 morphological features of the AV applies only to those aged <35 years; and (D) is redefined as pathological AR with ≥2 morphological features of RHD of the MV. A separate "borderline RHD" category (applicable only to those aged ≤20 years) was also introduced, with 3 subcategories: (A) at least 2 morphological features of RHD of the MV without pathological MR or MS, (B) pathological MR alone, and (C) pathological AR alone.

The 2023 WHF update revised Doppler thresholds for pathological regurgitation, notably introducing weight-based MR jet length criteria (≥1.5 cm for individuals weighing ≤30 kg; ≥2.0 cm for individuals weighing ≥30 kg), replacing the uniform ≥2 cm threshold from 2012. Of note, the inter-rater reliability of the 2012 WHF criteria for specific RHD classification categories (borderline vs. definite, and subcategories) is only fair (κ = 0.51), highlighting the challenge of consistent classification across observers.

A 2026 review by Zühlke et al. references 2024 WHO recommendations as providing an additional global framework for ARF/RHD management and classification, though the primary WHO guideline document should be consulted directly for specific recommendations. National ARF guidelines from RHDAustralia (2020) and the New Zealand Heart Foundation (2014, updated 2019) provide additional region-specific classification frameworks for high-risk populations and may be consulted for local clinical guidance.

High-Yield Clinical Pearls

• Chorea and indolent (insidious-onset) carditis are the only two manifestations that do not require evidence of preceding GAS infection for ARF diagnosis.
• PR prolongation cannot be used as a minor criterion if carditis is already counted as a major criterion in the same patient.
• Joint manifestations can only be counted in one category (major OR minor) per patient — never both.
• In moderate/high-risk populations, monoarthralgia alone can serve as a minor criterion, substantially lowering the diagnostic bar.
• The addition of subclinical carditis and monoarthritis to the criteria increased sensitivity in high-risk populations. Application of the 2015 modifications (subclinical carditis, monoarthritis, lower fever threshold) to a North Queensland cohort increased diagnostic sensitivity from 71.4% to 91.8% compared with the 1992 criteria.
• The 2015 AHA statement uses ≥38.5°C/≥38°C and CRP ≥3.0 mg/dL for fever and CRP thresholds, while Hirani et al. (Lancet 2025) uses >38.5°C/>38°C and CRP >3 mg/dL (strictly greater than). The table above follows the AHA formulation. In practice these distinctions are rarely consequential, but clinicians should be aware of the minor discrepancy between sources.

Common Pitfalls

• Applying low-risk population criteria in endemic settings leads to missed diagnoses. Clinicians in moderate/high-risk regions should use the more sensitive thresholds.
• Diagnosing ARF without documenting GAS infection (except for chorea and indolent carditis) is insufficient; GAS evidence is mandatory.
• Counting arthritis as both a major and minor criterion is incorrect; joint findings can only be used once.
• Ignoring subclinical carditis by failing to perform echocardiography can miss a substantial proportion of carditis cases, potentially leaving patients without secondary prophylaxis.
• Confusing "possible ARF" with "no ARF": Patients with possible ARF require close follow-up and, in many guidelines, initiation of secondary prophylaxis while awaiting further clarification.
• Overlooking the lower diagnostic threshold for recurrent ARF (3 minor criteria alone can suffice).