The interconnected relationship between humans, animals, and the environment has increased human exposure to a wide range of animal species, including insects. These insects, which are distributed globally, interact with humans in various environments and habitats across the planet. In this context, wasps (Vespidae), bees (Apidae), and hornets (Vespidae), which belong to the order Hymenoptera (Wani et al., 2014), are responsible for a significant number of stings worldwide and account for the majority of hypersensitivity reactions to insect stings (Diaz, 2009). The burden of these reactions is difficult to estimate; however, some reports suggest that they account for nearly 100 million cases per year, ranging from local reactions to fatalities caused by anaphylactic shock (Feás, 2021). Although stings are more common among young adult males engaging in outdoor activities, every age group is vulnerable (Smallheer, 2013). Allergic reactions are the most common medical consequence, affecting up to one-third of victims, including those with no prior history of allergies (Diaz, 2009).

The sting mechanism and type of venom exhibit chemical, molecular, and other similarities between bees and wasps (Habermann, 2013). Bees inflict a single sting, and their stingers detach, whereas wasps can inflict multiple stings because their stingers have fewer barbs and can be easily removed without detaching (Diaz, 2009). The venoms of bees and wasps differ in composition; for example, bee venom contains melittin, while wasp venom includes a protein known as antigen 5, which is found in the venom of hornets, yellowjackets, and other wasps, and is a significant allergen for individuals sensitive to insect stings (Kochoumian and Lam, 1987). Both venoms also contain hyaluronidases and phospholipases, which produce various effects on the human body (Diaz, 2009; Wani et al., 2014). The most common effects are those associated with the cardinal signs of inflammation, including edema, erythema, burning, pruritus, urticaria, and angioedema, which usually resolve within 24 h (Gupta, 2020). More severe, though less common, complications have been described, including anaphylactic shock and hypotension, as well as myocardial infarction, acute renal failure, pulmonary hemorrhage, rhabdomyolysis, acute hemorrhagic pancreatitis, atrial fibrillation, seizures, disseminated intravascular coagulation (DIC), intracranial hemorrhages, and cerebral infarctions (Temizoz et al., 2009; Gupta, 2020). An insightful classification by Müller in 1990 categorized reactions to Hymenoptera stings into four types: local, large local, systemic (grades I to IV), and unusual delayed reactions. Neurological complications, including strokes, fall into the category of unusual delayed reactions (Müller, 1990).

Among the rarest yet most severe consequences of bee and wasp envenomation are ischemic or hemorrhagic strokes (Temizoz et al., 2009; Kulhari et al., 2016). Although vascular complications following bee or wasp stings are rare, they should not be overlooked, as their consequences can create a significant burden and have a greater individual impact than other symptoms. The mechanisms by which bee and wasp stings can cause strokes are not fully understood, but several hypotheses have been proposed (Kulhari et al., 2016; Gupta, 2020; Kabra et al., 2022). These mechanisms include hyperactivity of the immune system, global cerebral hypoperfusion, retrograde stimulation of the superior cervical ganglion, disseminated intravascular coagulation, and vasoconstriction, which can lead to cellular hypoxia, ischemia, and subsequent necrosis of neural tissue (Yang et al., 2022). This is related to the action of venom components such as histamine, thromboxane, leukotrienes, and other vasoactive and inflammatory mediators that induce platelet aggregation and vasoconstriction (Mahale et al., 2016; Dalugama and Gawarammana, 2018; Gupta, 2020).

Despite the limited understanding of the mechanisms due to the rarity of these events, their widespread geographical distribution, and the lack of extensive research, we believe it is crucial to report, summarize, and consolidate the information on this topic. The consequences can be devastating not only for the patient but also for their family and the healthcare system. Therefore, this article aims to integrate and analyze information related to ischemic and hemorrhagic strokes associated with bee and wasp stings.

A total of 28 studies were included in this systematic review. Following the quality assessment of the studies using the JBI Critical Appraisal Checklist for Case Reports, 25 were rated as high quality with a score of 8, and 3 as moderate quality with a score of 7 (Supplementary Table S2). Among the 29 stroke cases identified, 14 (48.3%) were due to bee stings and 15 (51.7%) were due to wasp stings. The mean age of the patients was 45.79 years (SD 15.6). Almost all cases were recorded in males, with 28 (96.6%) of cases. Ischemic stroke was the most frequent type, occurring in 26 (89.7%) cases.

Clinical manifestations associated with these strokes varied but predominantly affected the nervous system, followed by respiratory complications. The most common symptoms included hemiparesis, aphasia, and facial nerve palsy. Detailed characteristics and clinical findings of the patients are summarized in Table 1.

Following the analysis of clinical data, it is essential to examine both the demographic and clinical distribution of the cases included in this review. The demographics offer valuable insights into factors such as age, gender, and the type of stroke associated with bee or wasp stings, which can influence the likelihood of stroke following envenomation, as presented in Figure 2.

This systematic review aimed to consolidate existing information to evaluate the potential risk of wasp and bee stings in triggering strokes in humans. Although millions of stings from these insects occur annually worldwide, these incidents generally result in localized reactions, such as severe pain, edema, and swelling at the sting site. These symptoms typically resolve within a few hours or days and are not usually life-threatening (Gupta, 2020). In cases where the sting causes more severe reactions, symptoms often have a delayed onset, making diagnosis more challenging. For example, the time between envenomation and the onset of stroke symptoms can range from 15 min to 4 days, with a median onset time of 16 h (Moein and Zand, 2017). In most of these cases, it is more likely that a bee or a wasp will cause the negative health consequences. However, systemic toxic reactions due to the venom compounds of these insects are usually observed after 50 to 100 bee stings (Bilir et al., 2013). The occurrence of a stroke as a consequence of venom exposure is generally rare, with only a few reports in the literature until the third decade of the 21st century. Stroke development is not always linked to the number of stings, whether multiple or single, but rather depends on the individual’s idiosyncratic response, their unique physiological reactions, and any preexisting risk factors (Moein and Zand, 2017).

In this review, we observed that the available literature was limited to case reports, identifying a total of 28 reports documenting 29 cases. Notably, almost all reported cases (28 of 29) occurred in males, aligning with the higher incidence of stings in men (Table 1). According to Linard et al., 68.2% of bee stings occurred in men; similar results were found by Diniz et al., who reported that 64.2% of the 1,307 stings recorded between 2007 and 2013 occurred in males (Linard et al., 2014; Diniz et al., 2016). This could be explained by the greater inclination of men to engage in outdoor activities. Additionally, there was an almost equal distribution of cases caused by bees and wasps, preventing the association of stroke with either species specifically.

In general, insect stings from the order Hymenoptera, which includes bees and wasps, usually cause uncomplicated local reactions such as pain, swelling, erythema, and bleeding at the sting site. Xi et al., in their study, described the clinical manifestations of patients with severe wasp stings and toxic reactions, highlighting renal and hepatic injury, rhabdomyolysis, hypotension, pulmonary edema, and hemolysis (Xie et al., 2013; Arif and Williams, 2025). Similarly, Cavalcante et al. reported a wide range of clinical complications resulting from bee stings some similar to those caused by wasp stings, as previously described; other clinical manifestation include atrial fibrillation, pericardial effusion, pericarditis, gastrointestinal bleeding, subconjunctival hemorrhage, encephalitis, and Guillain-Barré Syndrome (Cavalcante et al., 2024). It has also been reported that both bee and wasp stings can, in rare cases, lead to serum sickness, vasculitis, thrombocytopenic purpura, and various neurological, renal, or cardiovascular diseases (Przybilla and Ruëff, 2012). In our review, we observed that the majority of patients who develop a cerebrovascular accident present with neurological manifestations, the most frequent being right hemiparesis and facial nerve palsy, followed by altered consciousness, speech and language disturbances, and aphasia. Another common symptom in this group of patients is hypertension.

Post-mortem studies of patients who died from wasp stings reveal that the most common damage was to the nervous system, present in 70% of cases, with cerebral edema, intraventricular hemorrhage, and cerebral petechiae being the most frequent alterations (Day, 1962). The main type of stroke identified was ischemic (89.7%). However, the exact mechanism by which these stings can trigger a stroke is not fully understood. Several theories have been proposed (Figure 4). Regarding ischemic stroke, it has been suggested that bee venom toxins may cause hemolysis and endothelial damage, leading to the release of tissue thromboplastins and potentially promoting a state of disseminated intravascular coagulation (DIC), with blood vessel occlusion by fibrin thrombi (Jain et al., 2012). Additionally, bee venom contains vasoactive peptides such as thromboxane, which may cause vasoconstriction and result in ischemic stroke (Yang et al., 2022). In terms of hemorrhagic stroke, it has been described that changes in blood pressure induced by vasoactive amines released during mast cell degranulation, along with the effects of catecholamines triggered by melittin and histamine, may lead to a hypertensive state, increasing the risk of hemorrhagic stroke (Yang et al., 2022; Reddy et al., 2023). Another theory proposes that a decrease in blood pressure caused by the action of histamine and prostaglandin-2 could result in cerebral hypoperfusion and an increased risk of bleeding due to the anticoagulant activity of hyaluronidase and hemolysis mediated by phospholipase A2 (Yang et al., 2022; Reddy et al., 2023). Another proposed mechanism in the development of stroke involves hyperactivity of the immune system (Figure 4) (Yang et al., 2022).

Despite the uncertainty regarding the mechanisms of stroke production, the management of these patients should include prompt recognition and collaboration with experienced physicians to ensure the administration of specialized treatments (Jain et al., 2012). It should be noted that there are currently no protocols or clinical practice guidelines for the treatment of cerebral infarction associated with bee or wasp stings. In the case of bees, it is recommended to remove stingers embedded at the sting site as soon as possible, as they continuously inject venom (Yang et al., 2022).

In today’s world, as more people live on the edges of agricultural zones and in proximity to fields, bees and other stinging insects increasingly find themselves nesting in homes or buildings close to human activity; furthermore, climate change may be indirectly exacerbating risks related to animals and has significant impacts on venomous species (da Silva Freitas et al., 2024). This shift underscores the importance of public health awareness and a One Health approach, which recognizes the interconnectedness of human, animal, and environmental health. Proactive measures and education are crucial to prevent and manage the potential health risks posed by these insects as their interactions with humans become more frequent.

Among the limitations of this study is that it was carried out based on case reports which, due to their nature and the fact that they do not have control groups, do not allow establishing a causal relationship. Furthermore, these studies do not allow us to identify risk factors that predispose to the development of stroke after the sting of bees or wasps, as well as an average number of stings to develop it. Although most case reports do not specify the species involved, in certain instances Vespa velutina has been identified (Ciron et al., 2015). This invasive species, already established in Europe, Japan, and South Korea, has been linked to increased sting-related morbidity and mortality. In Europe, some regions have reported sting-related death rates as high as 2.22 per million inhabitants annually, largely attributed to Vespa velutina (Feás, 2021). It is also important to highlight the potential for publication bias, as the reported cases are likely to represent primarily those with severe clinical manifestations following bee or wasp stings. In contrast, cases with mild or transient symptoms may go unreported. The possibility of underreporting constitutes another significant limitation, as it hinders a comprehensive understanding of the problem. This substantially limits the ability to analyze both the clinical spectrum and the true epidemiological burden of these events. Underreporting may be partly due to the fact that many of these cases occur in low- and middle-income countries or in rural areas with limited access to healthcare services, which affects the diagnosis, management, and reporting of such cases. Finally, the presence of confounding factors cannot be ruled out, as many reports lack information on concurrent exposures, lifestyle habits such as tobacco, alcohol, or other substance use, and family history of cerebrovascular disease. These factors may independently influence or contribute to the observed risk, limiting causal interpretation.

Although cerebrovascular events such as ischemic and hemorrhagic strokes following bee or wasp stings are rare, scientific evidence confirms that the risk is real and should not be underestimated. The profound impact of a stroke extends far beyond the initial event, often resulting in life-altering consequences for affected individuals and placing a significant burden on healthcare systems. Given the severity of these outcomes, hospitals and healthcare centers must remain vigilant in recognizing and managing these potential complications.

Protocols should be established to ensure the timely diagnosis and treatment of these rare but serious events. Neuroimaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) should be performed in patients presenting with neurological symptoms (e.g., headache, loss of consciousness, speech disturbances, limb weakness, seizures, among others), whether these occur during initial medical evaluation, hospitalization, or after discharge. Additionally, the implementation of clinical observation protocols is essential. Observation periods ranging from 24 to 48 h may be warranted, depending on the severity of symptoms or the presence of comorbidities or risk factors that may increase the likelihood of cerebrovascular events. It is also necessary to train healthcare personnel to recognize these rare but potentially life-threatening complications and to strengthen reporting and case documentation systems to enhance epidemiological surveillance.

Moreover, considering the increasing interaction between humans and stinging insects especially in areas where urban development encroaches on natural habitats public health initiatives should emphasize awareness and preparedness. Continued research, particularly using animal models, is essential to better understand the pathophysiology of stroke following bee and wasp stings and to identify the specific species most likely to cause such complications.