Systemic Symptoms Following a Wolf Spider Bite in a Child

Abstract

Wolf spiders are widespread globally, but there are limited reports of wolf spider envenomation in the United States. Wolf spider bites are generally considered to be minimally consequential, with most reported bites causing only mild local symptoms. We present a case of systemic symptoms following a wolf spider bite in a 10-y-old boy in Texas. The patient experienced immediate onset of nausea, vomiting, severe abdominal pain, and headache within minutes of the bite. His symptoms resolved within 3 h with supportive care, and he was discharged without complications. This case involved vomiting and other systemic effects after a wolf spider bite. This differs significantly from envenomation effects commonly described with wolf spiders, which typically involve only mild local effects at the location of the bite.

Introduction

Wolf spiders (family Lycosidae) are a diverse group of arachnids with 2419 species within 124 genera found on every continent except Antarctica. They are adaptable predators that can be active during both day and night. They vary greatly in size, ranging from as small as 2 mm to as large as 35 mm in adulthood. Wolf spiders inhabit a wide range of environments, including forests, grasslands, wetlands, and coastal areas, often seeking shelter under rocks, logs, and leaf litter. They do not produce webs to catch their prey but rather rely on their strong chelicerae and venom to hunt and subdue prey. Their powerful jaws not only aid in capturing prey but also serve as a means of self-defense.

Wolf spider bites are typically associated with mild local symptoms, as described in case reports and studies from Brazil and Australia. These publications commonly report generally mild pain as the primary symptom of these bites, with other mild local symptoms including puncture marks/bleeding, swelling, itchiness, and redness. However, in an analysis of Australian wolf spider bites, minor systemic symptoms occurred in 7% of cases (3 patients), with symptoms including nausea (2 patients), headache (1 patient), and malaise (1 patient). Wolf spider bites are sometimes characterized as necrotic in review literature, but there is contention as to whether wolf spider bites result in skin necrosis.^1–4

We present a case of a 10-y-old boy who had a painful wolf spider bite to the thigh followed by severe vomiting, abdominal pain, and headache within minutes of the bite.

Case Report

A 10-y-old boy presented to an emergency department for care with complaints of vomiting, abdominal pain, and headache with onset minutes after a spider bite. He was reportedly in his home cleaning when he noticed a sharp pain on his thigh just above his knee. He noticed a spider at that site that jumped off his leg. The spider was immediately caught intact and held in a plastic bag (Figure 1).

Figure 1.

Wolf spider specimen captured after bite.

The patient had transient pain at the site of bite and within minutes developed nausea and vomited 5 to 6 times. Minutes later he felt the onset of abdominal pain and headache that he rated on a pain scale as 10/10 for each, respectively. He presented for emergency care ∼60 min after the bite, at which time his vital signs were temperature 37°C, blood pressure 109/66 mm Hg, heart rate 97 beats/min, respiration rate 18 breaths/min, and SpO₂ 100%.

The patient still had abdominal pain and headache that was 10/10 in pain severity. His physical examination was unremarkable except for rigid rectus abdominus tone. There was no skin abnormality at the bite location other than a tiny pinpoint pink area that was presumably the puncture location. The patient was treated with ondansetron 4 mg intravenously, acetaminophen 448 mg by mouth, and ibuprofen 300 mg by mouth, and investigations including complete blood count and comprehensive metabolic profile were obtained. The results of the investigations were complete blood count: white blood cells 28,000/mm², hemoglobin 15 g·dL^–1, platelets 395,000/microliter, neutrophils 81.8%; serum electrolytes: sodium 141 mEq·L^–1, potassium 3.3 mEq·L^–1, chloride 109 mEq·L^–1, carbon dioxide 17 mEq·L^–1, calcium 10.1 mg·dL^–1, and glucose 86 mg·dL^–1. Urinalysis was normal, with no evidence of hemolysis, including no detected blood or red blood cells.

The patient's pain resolved over 120 min, and by 150 min he reported feeling asymptomatic. After becoming asymptomatic, the patient took and tolerated oral feeding and was discharged from the emergency department 4 h after presentation. By telephone follow-up, the patient reported no further pain and no irritation, rash, or skin changes at the location of the bite. Examination of the preserved intact spider by a regional entomologist confirmed it to be a female wolf spider (Rabidosa rabida).

Discussion

This case involved a wolf spider bite that was particularly credible because the family caught the spider and presented it intact, allowing for easy identification. Lycosidae bites are generally considered less venomous to humans than other venomous spider bites, but Lycosidae themselves are more aggressive than other US venomous spiders, likely because their natural behavior requires active hunting of prey rather than use of webs to capture prey for consumption. Misidentification of the involved spider or whether any envenomation occurred at all is considered a major shortcoming of many reported cases of spider envenomation, ⁵ and this is a possibility in this case as well.

Texas has 86 documented species of Lycosidae. ⁶ The most common include the rabid wolf spider (R rabida), which is considered the most aggressive; the dotted wolf spider (Rabidosa punctulata); burrowing wolf spiders (Geolycosa sp); and the Hogna genus that includes the Carolina wolf spider, which is the largest Lycosidae in the United States.

Other Texas spiders with reported human bites include the Texas brown tarantula (Aphonopelma sp), which are the largest Texas spiders, and they may cause minor irritation to humas through urticating hairs in addition to rarely reported bites. Other species with reported envenomation are orb weavers, particularly Argiope aurantia, which inflict painful bites, and yellow sac spiders (Cheiracanthium sp), which inflict painful bites with subsequent necrosis, ⁷ reported elsewhere in the United States ⁸ and globally ⁹ but not in Texas. The strength and veracity of reports of necrotic aranchidism caused by Cheiracanthium sp in the United States were questioned in a 2006 review of all reported US and Australian cases at that time. ¹⁰

The patient's systemic symptoms in this case were atypical and differed from the effects most often reported for wolf spider envenomation. The most common spider envenomations in Texas are due to Loxoceles sp (brown recluse) and Latrodectus sp (black widow), which are both capable of causing systemic illness.^11,12 The patient's abdominal cramping and rigidity were like that widely described occurring after black widow envenomation, ¹² but in this case the abdominal pain and rigidity improved rapidly. Although the patient's vomiting could be potentially considered an anaphylactic effect, the lack of any other symptoms, including no pulmonary, airway, dermatologic, or cardiovascular symptoms, suggests that he did not have anaphylaxis. He was not given any medication such as an epinephrine, an antihistamine, or steroid that might treat anaphylaxis. Vomiting has not been reported previously secondary to wolf spider bites, although nausea has. This patient had a moderately low serum HCO₃ level of 17 mEq·L^–1, which commonly may be associated with mild acidemia such as may occur from dehydration or repeated vomiting.

Conclusions

This child's clinical presentation of illness after wolf spider bite was unique and was in several ways like other more common venomous spider bites, including black widow and/or brown recluse spider bites occurring in Texas and the United States. Vomiting may occur after black widow envenomation and, rarely, after brown recluse envenomation, and abdominal pain is often reported after black widow envenomation. When managing bites from unidentified spiders or bites from wolf spiders, clinicians should consider the possibility that such bites may result in systemic symptoms such as those experienced by the patient described in this case report.

Previous Presentation

This paper was presented at the Asia Pacific Association of Medical Toxicology Meeting, in Penang, Malaysia, November 2024.