Host-Metabolic Profiles in Recurrent Fever: Clinical Mechanisms, Implications, and Advances

Abstract

Recurrent fever syndromes represent a significant clinical challenge due to their heterogeneous etiologies, variable presentation, and overlapping features with infectious, autoimmune, and autoinflammatory disorders. Recent research has illuminated the integral role of host-metabolic profiles in both the pathophysiology and clinical manifestation of recurrent fevers, offering novel diagnostic and therapeutic insights. This comprehensive review synthesizes current evidence on the epidemiology, underlying mechanisms, risk factors, clinical spectrum, diagnostic strategies, and management options for recurrent fever, emphasizing host-metabolic interactions and recent advances in the field. Practical implications for clinicians are discussed, with recommendations grounded in recent guidelines and expert consensus.

Introduction

Recurrent fever, defined as three or more discrete episodes of elevated temperature separated by disease-free intervals, is a clinical presentation encountered across age groups and medical specialties. While infections remain a common cause, a substantial subset of patients present with fevers attributable to autoinflammatory, autoimmune, or metabolic dysregulation. The recent focus on host-metabolic profiles has unveiled critical insights into disease mechanisms, particularly in syndromes such as familial Mediterranean fever (FMF), periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome, and other monogenic autoinflammatory conditions. Understanding these metabolic underpinnings is essential for accurate diagnosis, risk stratification, and personalized management.

Epidemiology / Disease Burden

Recurrent fever syndromes, though less prevalent than acute febrile illnesses, account for a notable proportion of pediatric and adult rheumatology referrals. FMF is most prevalent among individuals of Mediterranean descent, with a carrier rate reaching up to 1 in 5 in certain populations. PFAPA is the most common periodic fever syndrome in children, with variable regional incidence. The true prevalence of metabolic and autoinflammatory fever syndromes is likely underestimated due to diagnostic complexity and phenotypic overlap. The burden includes diagnostic delays, unnecessary investigations, recurrent hospitalizations, and impaired quality of life, underscoring the need for heightened clinical awareness and improved diagnostic algorithms.

Pathophysiology

Emerging evidence emphasizes the interplay between host immunity and metabolic pathways in the genesis of recurrent fevers. Genetic defects in inflammasome proteins (e.g., MEFV, NLRP3, TNFRSF1A) lead to dysregulated interleukin-1β (IL-1β) and other proinflammatory cytokines, driving periodic inflammatory surges. Metabolic reprogramming of innate immune cells, including increased glycolysis and altered mitochondrial function, contributes to sustained inflammation and fever propagation. Additionally, dysregulated lipid metabolism, oxidative stress, and mitochondrial dysfunction have been implicated in the amplification of inflammatory cascades. This host-metabolic axis influences both the frequency and severity of febrile episodes, and may explain inter-individual variability in clinical expression.

Risk Factors

Risk factors for recurrent fever syndromes include genetic predisposition (e.g., MEFV mutations in FMF, MVK mutations in hyper-IgD syndrome), ethnic background, and family history of autoinflammatory diseases. Environmental triggers such as infections, stress, and temperature fluctuations may precipitate episodes in susceptible individuals. Metabolic comorbidities, including obesity, metabolic syndrome, and mitochondrial disorders, can modulate immune responses and increase susceptibility to recurrent fever, highlighting the importance of comprehensive metabolic assessment in affected patients.

Clinical Features

Clinically, recurrent fever syndromes present with stereotypical episodes of high-grade fever accompanied by variable systemic and organ-specific manifestations. FMF typically features abdominal pain, serositis, and arthralgia; PFAPA is characterized by periodic fever, aphthous ulcers, pharyngitis, and cervical adenitis. Other syndromes may present with urticarial rash, myalgia, lymphadenopathy, or hepatosplenomegaly. The periodicity, duration, and associated symptoms provide important diagnostic clues. Notably, host-metabolic profiles can influence symptom severity, duration of episodes, and response to therapy.

Diagnosis

Diagnosis of recurrent fever syndromes is grounded in detailed history, clinical criteria, and exclusion of infectious and malignant causes. Advances in genetic testing, including next-generation sequencing panels, permit identification of pathogenic variants in relevant genes. Biomarkers such as serum amyloid A, C-reactive protein, and proinflammatory cytokines may support diagnosis and monitoring. Metabolic profiling, including assessment of mitochondrial function and metabolic intermediates, is increasingly recognized as a valuable adjunct to traditional diagnostic paradigms, particularly in atypical or treatment-refractory cases.

Treatment & Management

Management strategies are tailored to the underlying etiology and host-metabolic context. NSAIDs and corticosteroids remain mainstays for acute symptom relief. Colchicine is the cornerstone for FMF, while tonsillectomy may benefit select PFAPA cases. In patients with IL-1-driven autoinflammatory syndromes, biologic agents targeting IL-1 (anakinra, canakinumab) or TNF-α (etanercept) have demonstrated efficacy. Metabolic interventions, including dietary modification, antioxidant therapy, and mitochondrial support, have shown promise in modulating disease activity and reducing episode frequency in select cohorts. Management of comorbidities and patient education are essential for optimizing outcomes.

Recent Advances / Emerging Therapies

Recent advances include the application of metabolomics and transcriptomics to delineate host-metabolic signatures predictive of disease activity, treatment response, and long-term prognosis. Novel therapeutics targeting inflammasome activation, mitochondrial function, and metabolic checkpoints are under investigation. Gene editing and personalized medicine approaches hold potential for curative interventions in monogenic syndromes. Early identification of high-risk metabolic profiles may enable preemptive interventions and improved disease control.

Guideline Recommendations

Current guidelines from the European League Against Rheumatism (EULAR) and other bodies emphasize a stepwise diagnostic approach, incorporating clinical criteria, genetic testing, and exclusion of mimickers. Treatment recommendations prioritize evidence-based use of colchicine, corticosteroids, and biologics, with consideration of metabolic comorbidities and individualized risk assessment. Regular monitoring, patient education, and multidisciplinary collaboration are advocated to optimize long-term outcomes.

Conclusion

Host-metabolic profiling represents a paradigm shift in the understanding and management of recurrent fever syndromes. Integration of metabolic and immunologic data into clinical practice offers opportunities for earlier diagnosis, tailored therapy, and improved prognosis. Continued research into the metabolic underpinnings and therapeutic targeting of host pathways will further refine management strategies and enhance patient care in this complex and evolving field.