Drug-induced systemic vasculitis (DISV) is an important and often underrecognized subset of vasculitic syndromes triggered by exposure to various pharmacological agents. Representing approximately 10-20% of vasculitis cases, DISV primarily affects small to medium-sized vessels and can manifest with a wide spectrum of cutaneous and systemic features. The pathogenesis involves complex immunological mechanisms, including hypersensitivity reactions, immune complex deposition, and direct endothelial injury, with emerging evidence of non-classical pathways contributing to refractory disease. Diagnosis relies on a high index of suspicion, detailed drug history, serological testing, and histopathological confirmation. Management centers on prompt withdrawal of the offending drug, supplemented by immunosuppressive therapy in severe or refractory cases. Prognosis is generally favorable with early intervention, but systemic involvement can lead to significant morbidity. This review synthesizes current knowledge on DISV, highlighting epidemiology, pathophysiology, clinical presentation, diagnostic challenges, therapeutic strategies, and future research directions.

• Drug-Induced Vasculitis; Systemic Vasculitis; Leukocytoclastic Vasculitis; Hypersensitivity Vasculitis; Immunopathogenesis; Diagnosis; Management; Prognosis; Biologic Agents; Antiplatelet Drugs.

Andrès E, Terrade JE, Jannot X, Lorenzo-Villalba N (2026) Drug-Induced Systemic Vasculitis: A Comprehensive Review. Ann Vasc Med Res 13(1): 1197.

Systemic vasculitis represents a diverse group of disorders characterized by inflammation and necrosis of blood vessel walls, which can lead to ischemia, tissue damage, and organ dysfunction. Drug-induced systemic vasculitis (DISV) is a clinically significant subset triggered by exposure to various pharmacological agents, accounting for approximately 10-20% of vasculitis cases [1].

The challenge in DISV lies in its clinical and pathological overlap with primary vasculitis, making diagnosis difficult. Moreover, the pathogenesis involves complex immune and non-immune mechanisms that are not fully elucidated.

Recent advances in immunology, pharmacogenomics, and molecular pathology have begun to shed light on these mechanisms, offering potential for improved diagnostic and therapeutic strategies.

This review aims to provide a comprehensive synthesis of current knowledge on DISV, emphasizing epidemiology, pathophysiology, clinical features, diagnosis, management, prognosis, and future research priorities.

Drug-induced systemic vasculitis (DISV) is uncommon but clinically significant. Drug exposure accounts for approximately 10–20% of cutaneous small-vessel vasculitis in clinical series, with an estimated annual incidence of ~15–20 cases per million inhabitants for drug associated cutaneous vasculitis. Among ANCA-associated vasculitis, drug-related forms constitute a minority but are well documented, particularly with antithyroid drugs and hydralazine.

Epidemiological data remain limited by underreporting and diagnostic challenges, highlighting the need for robust pharmacovigilance and registry-based studies to better define incidence, risk factors, and high-risk populations.

Although rare at the population level, reported cases are frequently severe, with high rates of organ involvement and non-negligible mortality in pharmacovigilance studies. The epidemiology of DISV is shaped by drug prescription patterns, genetic predisposition, and environmental factors. The latency period between drug exposure and vasculitis onset is highly variable, ranging from hours to several weeks or even months, complicating causal attribution [1].

Drugs most frequently implicated include antibiotics (beta-lactams such as amoxicillin, sulfonamides, and cephalosporins), NSAIDs, and antiplatelet agents (e.g., clopidogrel, ticagrelor), which can induce refractory systemic small-vessel vasculitis with extracutaneous involvement [2]. Biologic therapies, including rituximab and anti-TNF-alpha agents, paradoxically can both treat and trigger vasculitis [1-3]. The growing use of immune checkpoint inhibitors in oncology has also been associated with vasculitic syndromes, reflecting the expanding spectrum of drug-induced immune dysregulation (Table 1).

Table 1: Drugs Associated with Drug-Induced Systemic Vasculitis (DISV).

Legend: ANCA: Antineutrophil cytoplasmic antibodies; MPO: Myeloperoxidase; PR3: Proteinase 3; GN: Glomerulonephritis; DRESS: Drug Reaction with Eosinophilia and Systemic Symptoms; TNF-α: Tumor Necrosis Factor-alpha.

Drug-induced systemic vasculitis (DISV) is a heterogeneous disorder arising from a complex interplay of immune-mediated and non-immune mechanisms, resulting in inflammation and injury of small to medium sized blood vessels.

The classical pathway involves type III hypersensitivity reactions, in which circulating drug or drug-metabolite complexes deposit within vessel walls. These immune complexes activate the complement cascade, leading to recruitment of neutrophils and the release of reactive oxygen species and proteolytic enzymes, ultimately causing leukocytoclastic vasculitis characterized by fibrinoid necrosis and endothelial damage.

In addition to immune complex–mediated injury, T-cell–mediated delayed hypersensitivity contributes to the pathogenesis of DISV. In this mechanism, drug antigens are presented by antigen-presenting cells to T lymphocytes, triggering cytokine release and cytotoxic responses that further amplify vascular inflammation.

IgE-mediated immediate hypersensitivity reactions have also been implicated, particularly in cases with rapid onset cutaneous manifestations, urticaria, or angioedema, highlighting the role of humoral immune responses in small-vessel involvement [2].

Emerging evidence suggests that non-immunologic mechanisms may underlie refractory or atypical cases of DISV. These include direct endothelial toxicity from reactive drug metabolites, dysregulated neutrophil apoptosis, and perturbations in vascular homeostasis that bypass classical immune checkpoints [2]. Such mechanisms may account for severe systemic presentations or poor responsiveness to standard immunosuppressive therapy.

Molecular-targeted therapies and biologics can also induce vasculitis through immune modulation. These agents may alter cytokine networks, disrupt immune tolerance, or unmask subclinical autoimmunity, leading to the emergence of autoantibodies or small-vessel inflammation [3].

Finally, genetic and host factors are likely critical determinants of susceptibility. Polymorphisms affecting drug metabolism enzymes, immune regulatory pathways, and neutrophil function may modulate the likelihood and severity of DISV, although these associations remain incompletely characterized. 

Environmental triggers, co-medications, and underlying comorbidities further contribute to phenotypic variability, resulting in a spectrum of clinical presentations from isolated cutaneous vasculitis to severe multisystem involvement.

Overall, the pathophysiology of DISV is multifactorial, integrating immune complex formation, cellular hypersensitivity, endothelial toxicity, immune modulation by targeted therapies, and host genetic susceptibility. Understanding these intertwined mechanisms is essential for accurate diagnosis, risk stratification, and the development of targeted therapeutic interventions (Figure 1).

Figure 1 Pathophysiology of Drug-Induced Systemic Vasculitis (DISV).

Drug-induced systemic vasculitis (DISV) demonstrates a broad spectrum of clinical features, reflecting the variable size and distribution of affected vessels.

Cutaneous manifestations are most frequent, typically presenting as palpable purpura, urticarial lesions, necrotic ulcers, or, less commonly, bullous eruptions. Histopathologic examination often reveals leukocytoclastic vasculitis [1].

Systemic involvement may affect multiple organ systems. Renal manifestations include hematuria, proteinuria, and renal insufficiency. Pulmonary involvement can present as alveolar hemorrhage or nodular lesions. Gastrointestinal features range from abdominal pain to overt bleeding, while nervous system involvement may manifest as mononeuritis multiplex or peripheral neuropathy [2-4].

The temporal relationship between drug exposure and symptom onset, with resolution upon withdrawal, remains a key diagnostic criterion. Clinical overlap with primary vasculitis, particularly ANCA-associated vasculitis, can complicate diagnosis and underscores the importance of a thorough drug history.

Accurate diagnosis of drug-induced systemic vasculitis (DISV) requires a multidisciplinary approach integrating clinical, histopathological, and laboratory data. A comprehensive drug history is essential to identify potential offending agents, including prescription medications, over-the-counter drugs, and herbal supplements [1] (Figure 2). Establishing a temporal relationship between drug exposure and symptom onset is a critical diagnostic element.

Figure 2 Diagnostic Algorithm for Drug-Induced Systemic Vasculitis (DISV).

Histopathological examination of a skin or involved organ biopsy remains the diagnostic gold standard, typically demonstrating leukocytoclastic vasculitis characterized by fibrinoid necrosis of vessel walls, neutrophilic infiltration with nuclear debris, and immune complex deposition on immunofluorescence [1].

Serologic evaluation—including antineutrophil cytoplasmic antibodies (ANCA), antinuclear antibodies (ANA), complement levels, and targeted infectious serologies—is necessary to exclude primary systemic vasculitis and alternative etiologies [4]. Laboratory findings may overlap with idiopathic ANCA-associated vasculitis, particularly in cases related to antithyroid drugs or hydralazine.

Imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) are indicated when systemic organ involvement is suspected. Differentiating DISV from idiopathic vasculitis remains challenging due to overlapping clinical and serological features; however, clinical improvement following withdrawal of the suspected drug strongly supports the diagnosis.

Emerging biomarkers for drug-induced small vessel vasculitis (DISV) are under investigation to improve diagnosis and disease monitoring. Soluble markers of endothelial activation (e.g., ICAM-1, VCAM-1) and neutrophil-derived proteins such as S100A8/A9 have shown promise in reflecting vascular inflammation. Urinary soluble CD163 and serum PTX3 may help detect renal involvement and active vasculitic processes. While these biomarkers are promising, their clinical utility in DISV specifically remains to be validated in prospective studies.

The cornerstone of therapy in drug-induced systemic vasculitis (DISV) is prompt identification and discontinuation of the offending agent, which frequently results in rapid and sustained clinical improvement [1]. Early recognition is critical, as delayed drug withdrawal can lead to persistent or progressive organ involvement and complicate the clinical course. In cases confined to the skin, particularly when lesions are mild and non-ulcerative, supportive measures such as topical corticosteroids, antihistamines, and careful wound care are often sufficient to control symptoms and prevent secondary infection.

For moderate to severe presentations involving systemic organ systems—including renal, pulmonary, gastrointestinal, or neurologic involvement—systemic corticosteroids are typically indicated as first-line therapy. High-dose prednisone or methylprednisolone may be used initially to rapidly control inflammation, followed by a gradual taper tailored to clinical response. In patients who do not adequately respond to corticosteroids alone, adjunctive immunosuppressive agents such as cyclophosphamide, azathioprine, or cyclosporine may be employed to achieve disease remission and prevent relapses [1,2]. The choice of agent is guided by the severity of organ involvement, comorbidities, and risk of adverse effects.

Rituximab, a monoclonal anti-CD20 antibody, has emerged as a valuable therapeutic option in refractory or relapsing cases of vasculitic neuropathy and systemic vasculitis, including select instances of drug-induced disease. By depleting B cells and modulating autoantibody production, rituximab can achieve durable remission; however, its use must be approached with caution, as rare cases of drug-induced vasculitis have been reported with B-cell depletion therapy itself [5,6].

In addition to these established therapies, novel immunomodulatory agents targeting specific inflammatory pathways—such as cytokine inhibitors and small-molecule modulators of immune signaling—are under investigation.

These agents aim to reduce reliance on glucocorticoids, thereby minimizing long-term complications such as osteoporosis, diabetes, and cardiovascular risk [7].

Supportive care and monitoring are integral components of management. Patients receiving immunosuppressive therapy require close surveillance for infections, as immunosuppression increases susceptibility to bacterial, viral, and opportunistic pathogens. Cardiovascular risk factors should also be assessed and mitigated, particularly in patients receiving prolonged corticosteroid therapy. Renal function, complete blood counts, liver enzymes, and inflammatory markers should be monitored regularly to guide therapy adjustments and detect early treatment related toxicities.

Finally, patient education is crucial. Individuals should be counseled to avoid re-exposure to the offending drug and informed about the signs of recurrence or systemic involvement, facilitating prompt evaluation and intervention in case of relapse.

The prognosis of drug-induced systemic vasculitis (DISV) largely depends on the extent of systemic involvement, promptness of diagnosis, and withdrawal of the causative agent. Most patients experience resolution of symptoms with drug discontinuation and appropriate immunosuppression [1]. However, refractory cases, especially those involving vital organs such as kidneys and lungs, may progress to chronic organ damage or require long-term dialysis or respiratory support [2-4]. Cardiovascular complications are a significant concern, as systemic vasculitis and its treatment can accelerate atherosclerosis and increase myocardial infarction risk [8 10]. Mortality rates vary but can be substantial in severe systemic disease. Ethnic and demographic factors may influence disease severity and outcomes, highlighting the need for inclusive clinical trials.

Despite progress, many gaps remain in understanding drug-induced systemic vasculitis (DISV). Future research should focus on elucidating precise immunopathogenic mechanisms, including the role of genetic and epigenetic factors in susceptibility and refractory disease. Large-scale, prospective epidemiological studies and pharmacovigilance registries are needed to better define incidence, risk factors, and outcomes across diverse populations. Development of standardized diagnostic criteria and validated biomarkers specific to DISV would enhance early recognition and differentiation from primary vasculitis. Therapeutic research should prioritize targeted immunomodulatory agents with improved safety profiles and glucocorticoid-sparing effects [7]. Additionally, the impact of emerging therapies such as immune checkpoint inhibitors on vasculitis incidence warrants ongoing surveillance. Collaborative multidisciplinary efforts integrating clinical, immunological, and molecular data will be essential to advance personalized management strategies.

Drug-induced systemic vasculitis (DISV) represents a complex and heterogeneous group of disorders that can affect multiple organ systems, ranging from isolated cutaneous lesions to life-threatening systemic involvement. The condition poses significant diagnostic challenges, as its clinical presentation often overlaps with primary vasculitis, autoimmune disorders, and infectious or neoplastic mimics. Early recognition hinges on a careful drug history, attention to temporal relationships between drug exposure and symptom onset, and awareness of commonly implicated agents. Clinicians should maintain a high index of suspicion, particularly in patients presenting with new onset vasculitic features while on medications known to trigger immune-mediated reactions. Timely identification and cessation of the offending drug remain the cornerstone of management and are often sufficient to induce rapid clinical improvement, especially in cases limited to the skin. For patients with systemic involvement, early initiation of corticosteroids and adjunctive immunosuppressive therapy is critical to prevent irreversible organ damage. Practitioners should individualize therapy based on disease severity, organ involvement, comorbidities, and risk of adverse effects. In refractory cases, targeted biologic therapies such as rituximab may be considered, but their use requires careful monitoring due to potential paradoxical induction of vasculitis or increased infection risk. Practical considerations for the clinician include close monitoring of renal function, inflammatory markers, and hematologic parameters, as well as vigilance for infections and cardiovascular complications associated with immunosuppressive treatment. Patient education is equally important: individuals should be counseled on avoiding re-exposure to the offending drug and on early recognition of recurrent symptoms. Structured follow-up ensures prompt intervention in the event of relapse and allows for adjustment of immunosuppressive therapy. Looking forward, continued research is essential to refine diagnostic criteria, elucidate pathogenic mechanisms, and develop safer, more targeted therapies. Efforts to establish evidence-based management guidelines will aid clinicians in navigating this challenging condition and optimizing outcomes. Ultimately, a combination of heightened clinical awareness, judicious pharmacologic intervention, and longitudinal patient monitoring represents the most effective strategy for managing DISV in routine practice.

Key Messages for the Clinician

1. Always consider drug-induced causes in new-onset vasculitis, particularly with temporal correlation to medication initiation.

2. Immediate withdrawal of the suspected drug is the most effective first-line intervention.

3. Systemic involvement warrants early immunosuppressive therapy to prevent organ damage.

4. Close monitoring for treatment-related complications, including infections and cardiovascular risk, is mandatory.

5. Patient education and structured follow-up are essential to prevent recurrence and ensure safe long-term management.

E.A.: Conceptualization, manuscript drafting, literature review, critical revision of content. N.L.V.: Literature review, preparation of tables and figures, critical revision of manuscript. Both authors approved the final version of the manuscript and agree to be accountable for all aspects of the work.

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