Necrotic arachnidism

A brown recluse spider bite wound: a case report and literature review

DECLARATION OF INTEREST

The authors have no conflicts of interest.

Utilization of dapsone and hemoglobin in the epithelial skin regeneration therapy of cutaneous loxoscelism: A case report and integrative literature review

BACKGROUND

Loxosceles spp are arthropods found worldwide. Its bite may produce cutaneous loxoscelism (necrotic or edematous) or cutaneous-visceral loxoscelism. Depending on their severity and location, cutaneous forms are managed with local cold application and systemic administration of antihistamines, corticosteroids, antibiotics, polymorphonuclear inhibitors, and analgesics.

OBJECTIVE

This study aimed to report a case of cutaneous loxoscelism and to identify the main dermatological manifestations associated with the Loxosceles spp bite.

DESIGN AND SETTING

This case report and literature review was conducted in a Mexican university.

METHODS

A detailed report on the medical management of a patient with cutaneous loxoscelism treated at the emergency department of a public hospital was published. Scopus, PubMed, Web of Science, and Google Scholar databases were searched to identify articles reporting cutaneous loxoscelism. The following keywords were used during the database search: "loxoscelism" OR "spider bite," OR "loxosceles" OR "loxosceles species" OR "loxosceles venom" OR "loxoscelism case report" AND "cutaneous" OR "dermonecrotic arachnidism."

RESULTS

A 62-year-old female patient with cutaneous loxoscelism was treated with systemic dapsone and local heparin spray. Eighteen studies with 22 clinical cases were included in this systematic review. Of the 22 patients, 12 (54.5%) were men. L. rufescens was the predominant spider species.

CONCLUSIONS

The administration of dapsone and heparin for the management of cutaneous loxoscelism demonstrated success in this case, with no sequelae observed. In general, the literature review indicated favorable outcomes in patients treated with antimicrobials and corticosteroids, with continuous healing of skin lesions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID CRD42023422424 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023422424).

A Brief Overview of the Toxic Sphingomyelinase Ds of Brown Recluse Spider Venom and Other Organisms and Simple Methods To Detect Production of Its Signature Cyclic Ceramide Phosphate

A special category of phospholipase D (PLD) in the venom of the brown recluse spider (Loxosceles reclusa) and several other sicariid spiders accounts for the dermonecrosis and many of the other clinical symptoms of envenomation. Related proteins are produced by other organisms, including fungi and bacteria. These PLDs are often referred to as sphingomyelinase Ds (SMase Ds) because they cleave sphingomyelin (SM) to choline and "ceramide phosphate." The lipid product has actually been found to be a novel sphingolipid: ceramide 1,3-cyclic phosphate (Cer1,3P). Since there are no effective treatments for the injury induced by the bites of these spiders, SMase D/PLDs are attractive targets for therapeutic intervention, and some of their features will be described in this minireview. In addition, two simple methods are described for detecting the characteristic SMase D activity using a fluorescent SM analog, (N-[12-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]dodecanoyl]-SM (C12-NBD-SM), that is cleaved to C12-NBD-Cer1,3P, which is easily separated from other potential metabolites by thin-layer chromatography and visualized under UV light. Besides confirming that C12-NBD-Cer1,3P is the only product detected upon incubation of C12-NBD-SM with brown recluse spider venom, the method was also able to detect for the first time very low levels of activity in venom from another spider, Kukulcania hibernalis The simplicity of the methods makes it relatively easy to determine this signature activity of SMase D/PLD. SIGNIFICANCE STATEMENT: The sphingomyelinase D/phospholipase D that are present in the venom of the brown recluse spider and other sources cause considerable human injury, but detection of the novel sphingolipid product, ceramide 1,3-cyclic phosphate, is not easy by previously published methods. This minireview describes simple methods for detection of this activity that will be useful for studies of its occurrence in spider venoms and other biological samples, perhaps including lesions from suspected spider bites and infections.

Clinical Evolution After Administering Antivenom in Patients With Loxoscelism

Spiders are the most numerous arthropods of the arachnid class. More than 45 thousand species of spiders have been identified, and only a few are dangerous to humans. Among them, the "violin spider" or "brown spider" of the genus Loxosceles (family Sicariidae) has a worldwide distribution, and its bite can cause loxoscelism. Initial treatment of a Loxosceles spider bite includes application of local cold, rest, elevation of the extremity if possible, and systemic pharmacotherapy with antihistamines, corticosteroids, antibiotics, polymorphonuclear inhibitors, and analgesics or nonsteroidal anti-inflammatory drugs. During cutaneous or systemic loxoscelism, administration of Loxosceles antivenom (immunoglobulin (Ig)G F(ab')2 fragments) may be indicated to prevent progression to severe systemic phases. In this manuscript, we present three cases of patients with loxoscelism treated with the fabotherapeutic Reclusmyn®, developed and manufactured in Mexico. Two patients had a satisfactory outcome without severe skin or systemic damage. Only one patient with loxoscelism, despite early initiation of antivenom, had extensive skin lesions that healed satisfactorily, leaving only a non-disabling scar. Due to the global presence of this clinical problem, further studies are needed to establish local and general guidelines for the treatment and prevention of loxoscelism. This will allow health professionals to provide more efficient and higher quality medical care and feel supported in their decisions.

Brown recluse spider envenomation with systemic loxoscelism and delayed hemolysis: A case report

The brown recluse spider (Loxosceles reclusa) is endemic to the South, West and Central Midwestern United States, and envenomation from this spider can cause cutaneous and/or systemic symptoms. We present a case of systemic loxocelism in an adolescent male resulting in three emergency department visits and two hospitalizations for a rare case of delayed hemolysis 6 days after envenomation. A 19-year-old male presented to the emergency department twice within two days after envenomation with worsening pain, subjective fever, chills, nausea and vomiting. He required a two-day hospitalization for rhabdomyolysis and acute kidney injury. The patient was discharged with improving symptoms and laboratory results on day four before returning again on day seven with worsening symptoms. He was diagnosed with hemolytic anemia on day seven and was subsequently hospitalized for six days. This case of systemic loxoscelism manifested hemolysis six days after envenomation, following an improvement in symptoms and laboratory studies. This case highlights the need for continuous monitoring and/or follow-up in cases of systemic loxocelism.

Acute necrotic arachnidism with necrotising fasciitis and recurrent pneumothorax

A male infant presented with swelling of the left leg and fever. Over the next 2 days, the area developed fasciitis extending to the left thigh, abdomen, and lower chest. Meanwhile, the parents found a giant brown spider within the infant's cot belonging to the genus Loxosceles, otherwise called the brown recluse spider. The dermo-myonecrosis progressed to deeper tissues involving the lung parenchyma requiring invasive ventilation. CT of the thorax showed multiple pneumatoceles, and lung biopsy showed alveolar necrosis. The infant was treated with intravenous antibiotics and corticosteroids. We drained the pneumothoraces by thoracostomy and insertion of intercostal drainage tubes. The infant required respiratory support initially by conventional ventilation, which was escalated to high-frequency oscillatory ventilation. He had refractory hypoxaemia and died. This is the first fatal case of acute spider envenomation described in India. Spider envenomation must be considered in patients with sudden onset, rapidly progressive necrotising fasciitis unresponsive to antibiotic therapy.

Impact of antivenom administration on the evolution of cutaneous lesions in loxoscelism: A prospective observational study

BACKGROUND

Spiders of the genus Loxosceles are distributed throughout tropical and temperate regions worldwide. Loxosceles spp. bites may evolve to necrosis, with or without intravascular hemolysis. There is no consensus regarding the best treatment to prevent necrosis. The objective of this study was to evaluate the factors associated with the development of necrosis and the impact that antivenom administration has on the evolution of cutaneous loxoscelism.

METHODOLOGY/PRINCIPAL FINDINGS

This was a prospective observational study carried out at a referral center for envenoming. Over a 6-year period, we included 146 patients with a presumptive or definitive diagnosis of loxoscelism. Depending on the symptom severity, a polyvalent anti-arachnid antivenom was administered or not-in 74 cases (50.7%) and 72 cases (49.3%), respectively. Cutaneous and systemic manifestations were assessed at admission and weekly thereafter. Adverse reactions to the antivenom were also evaluated. Cutaneous loxoscelism was observed in 141 cases (96.6%), and the spider was identified in 29 (19.9%). The mean time from bite to antivenom administration was 41.6 ± 27.4 h. After discharge, 130 patients (90.9%) were treated with corticosteroids, antihistamines and analgesics being prescribed as needed. The probability of developing necrosis was significantly lower among the patients who were admitted earlier, as well as among those who received antivenom (p = 0.0245). Among the 74 patients receiving antivenom, early and delayed adverse reactions occurred in seven (9.5%) and four (5.4%), respectively. Local infection was observed only in three (2.3%) of the 128 patients for whom that information was available.

CONCLUSIONS/SIGNIFICANCE

Necrosis after a Loxosceles sp. bite appears to more common when hospital admission is delayed or when antivenom is not administered. In addition, the administration of a polyvalent anti-arachnid antivenom appears to be safe, with a relatively low rate of adverse reactions.

Suspected Brown Recluse Spider Envenomation: Missed Diagnosis and Delayed Treatment of Loxoscelism: A Case Report

CASE

We report the case of a previously healthy 51-year-old man who presented to our hospital after worsening clinical appearance of his left ring finger, despite antibiotics and previous surgical drainage for suspected abscess at an outside institution 3 weeks ago. He was admitted to our hospital for surgical debridement and decompression. After suspicion of cutaneous loxoscelism based on the clinical record and corticosteroid administration, the patient presented a favorable evolution.

CONCLUSION

Cutaneous loxoscelism caused by a spider bite is present in Europe, mainly in the Mediterranean area, and should be considered in cases of skin infections which do not respond to antibiotics.

A 14-Year-Old Boy With Neck Pain, Fevers, and Diffuse Erythematous Rash

A previously healthy 14-year-old boy developed right-sided neck pain, tachycardia, a diffuse erythematous rash, and subjective fevers over 2 days. He sought medical attention in a local urgent care clinic, where he had a negative Sars-CoV-2 antigen test and was referred to the local emergency department (ED) for persistent tachycardia and further workup. After fluid resuscitation, his tachycardia was not improved, so he was admitted to the Pediatric Hospital Medicine Service. Physical examination showed large areas of erythema and erythroderma of multiple body sites, perioral sparing, increased erythema in flexor skin folds, posterior soft palate petechiae, and a white strawberry tongue. There was a small, tender lesion with surrounding erythema without discharge on his right neck thought to be a possible entry point for infection. Laboratory results showed thrombocytopenia, normal white blood cell count, normal hemoglobin concentration, absolute lymphopenia, and an elevated C-reactive protein (CRP) to 130 mg/L. He was started on intravenous fluids and antibiotics for a presumed infectious cause of the rash and laboratory findings. The next morning, an expanded diagnostic workup was undertaken including electrocardiogram, echocardiogram, ferritin, triglycerides, liver enzymes, lactate dehydrogenase (LDH), brain natriuretic peptide, coagulation studies, and fibrinogen. With treatment and supportive care, his tachycardia and energy improved, so he was discharged with oral antibiotics and follow-up with the Infectious Disease Clinic in 2 days. When seen in follow-up, he was immediately admitted to the hospital for worsening fatigue, tachycardia, and new findings that prompted multiple consultations, and transfer to pediatric critical care services.

Venomous spiders of Albania –does an increase of temperature influence the toxicity of spider venom?

Black widow spiders (Latrodectus sp.) are distributed worldwide, and in Albania the L. tredecimguttatus Rossi, 1790 has been the dominant spider. Other medically important spiders in Albania include the brown recluse with symptoms known as loxoscelism, the false black widow and the egg sac spiders; the last two inducing similar symptoms to a wasp sting. Methods: The data analyzed is from a decade-long study of 125 patients hospitalized in the regional hospital of Fier County, in the Western Lowland of Albania from May 2009 and to October 2018. Objective: Although the venom is rarely fatal, the recent spider bites raise questions about the influence of higher air temperatures on their possibly increased toxicity. Results: Significantly the severity of the α-latrotoxin rises during the summer, when human–spider contact frequency is higher and when the black widow spiders have an increased motivation to protect their egg sacs. Conclusion: This study revealed an increased severity of the black widow bites with respect to patient health, shown via all the severe systemic symptoms, during those months with higher temperatures.

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The spider bites revealed a higher venom severity during summer, when there was a higher human-spider contact frequency.

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The longer recovery times are probably related to the quantity and toxicity of the spider venom á-latrotoxin.

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Extreme environmental conditions increase the spider motivation to protect the egg sac and self-protect.

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Higher environmental temperatures may thus lead to higher black widow venom toxicity during the hot summer months.

Validation of a colorimetric LAMP to detect Loxosceles experimental envenomation

Diagnostic tests for brown spider accidents are unavailable and impact treatment decisions, increasing costs and patient risks. In this work, we used for the first time a fast, simple, and visual method based on the loop-mediated isothermal amplification assay (LAMP) to detect Loxosceles envenomation. Using the DNA from L. similis legs, we observed a high sensitivity using this test since as low as 0.32 pg of DNA could be detected. This pH-dependent colorimetric assay was 64 times more sensitive than PCR to detect spider DNA. The test was specific for Loxosceles once no cross-reaction was observed when testing DNA from different agents that cause similar dermonecrotic injuries. The test allowed the detection of Loxosceles intermedia DNA from hair, serum, and exudate samples obtained from experimentally-envenomed rabbit within 72 h. The method sensitivity varied according to the sample and the collection time, reaching 100% sensitivity in serum and hair, respectively, 1 h and 24 h after the experimental envenomation. Due to its ease of execution, speed, sensitivity, and specificity, LAMP presents an excellent potential for identifying Loxosceles spp. Envenomation. This can reduce the burden on the Health System and the morbidity for the patient by implementing the appropriate therapy immediately.In addition, this work opens up the perspective to other venomous animal accident identification using LAMP.

Systemic loxoscelism induced warm autoimmune hemolytic anemia: clinical series and review

OBJECTIVES

Describe the development of warm autoimmune hemolytic anemia warm (AIHA) secondary to a brown recluse spider (Loxosceles reclusa) bite is known as systemic loxoscelism; and review epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

METHODS

Cases series of two cases of warm AIHA due to systemic loxoscelism and a review of the current literature: epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

RESULTS

Presented here are two cases of warm AIHA due to systemic loxoscelism. Each patient was generally healthy appearing and presented with symptomatic anemia in the setting of brown recluse spider bites. Both patients were eventually found to have warm AIHA. Upon recognition of the diagnosis, the patients were started on corticosteroids and aggressive intravenous fluid hydration. In addition, they received transfusions of packed red blood cells. Their clinical courses improved, and they recovered to eventually be discharged home.

CONCLUSION

Envenomation by a brown recluse spider, Loxosceles reclusa, can result in systemic loxoscelism which can cause warm AIHA. The diagnosis of warm AIHA is confirmed by the direct antiglobulin/Coomb's test. Warm AIHA can be a life-threatening disease process. Hemodynamic support with intravenous fluids and RBC transfusion is the initial step in the management of these patients. Corticosteroids are the mainstay of current management. Second line treatments include rituximab. Rarely patients require splenectomy for refractory disease. Corticosteroids should be tapered over a three-month period.

Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation

Background:

Although loxoscelism (bites by brown spiders of the genus Loxosceles) frequently results in dermonecrosis, no previous clinical reports have provided detailed temporal photodocumentation of the evolution of dermonecrotic lesions in a case series.

Methods

This was a retrospective cohort study involving a case series of loxoscelism. Only cases of dermonecrosis with photodocumentation of lesion evolution (from admission until complete or almost complete healing) were included.

Results:

Eight patients (six men, two women; median age, 38 years) fulfilled the inclusion criteria. The bite sites included the thigh (n = 4), forearm (n = 2), abdomen (n = 1), and trunk (n = 1). Time interval between the bite and first contact with our service ranged from 15 to 216 h (median = 29 h). The main clinical manifestations included local erythematous and ischemic violaceous lesions overlying a base of indurated edema (livedoid plaque, 8), local pain (8), exanthema (6), serohemorrhagic vesicles/blisters (5), fever (5), and jaundice (1). Based on a previously established classification, the cases were classified as probable cutaneous-necrotic loxoscelism (CNL, n = 4), presumptive CNL (n = 3), and presumptive cutaneous-hemolytic loxoscelism (n = 1). Seven patients were treated with anti-arachnidic antivenom (AV; median time post-bite = 46 h). Complete lesion healing ranged from 34 to 98 days post-bite (median, 68 days; six patients). None of the patients required reconstructive plastic surgery.

Conclusions

The sequential photographic documentation showed considerable variation in the process of wound healing, with complete epithelialization requiring up to 3 months after the bite.

Brown spider venom toxins: what are the functions of astacins, serine proteases, hyaluronidases, allergens, TCTP, serpins and knottins?

Accidents caused by the bites of brown spiders (Loxosceles) generate a clinical condition that often includes a threatening necrotic skin lesion near the bite site along with a remarkable inflammatory response. Systemic disorders such as hemolysis, thrombocytopenia, and acute renal failure may occur, but are much less frequent than the local damage. It is already known that phospholipases D, highly expressed toxins in Loxosceles venom, can induce most of these injuries. However, this spider venom has a great range of toxins that probably act synergistically to enhance toxicity. The other protein classes remain poorly explored due to the difficulty in obtaining sufficient amounts of them for a thorough investigation. They include astacins (metalloproteases), serine proteases, knottins, translationally controlled tumor proteins (TCTP), hyaluronidases, allergens and serpins. It has already been shown that some of them, according to their characteristics, may participate to some extent in the development of loxoscelism. In addition, all of these toxins present potential application in several areas. The present review article summarizes information regarding some functional aspects of the protein classes listed above, discusses the directions that could be taken to materialize a comprehensive investigation on each of these toxins as well as highlights the importance of exploring the full venom repertoire.

Prospective Use of Brown Spider Venom Toxins as Therapeutic and Biotechnological Inputs

Brown spider (genus Loxosceles) venoms are mainly composed of protein toxins used for predation and defense. Bites of these spiders most commonly produce a local dermonecrotic lesion with gravitational spread, edema and hemorrhage, which together are defined as cutaneous loxoscelism. Systemic loxoscelism, such as hematological abnormalities and renal injury, are less frequent but more lethal. Some Loxosceles venom toxins have already been isolated and extensively studied, such as phospholipases D (PLDs), which have been recombinantly expressed and were proven to reproduce toxic activities associated to the whole venom. PLDs have a notable potential to be engineered and converted in non-toxic antigens to produce a new generation of antivenoms or vaccines. PLDs also can serve as tools to discover inhibitors to be used as therapeutic agents. Other Loxosceles toxins have been identified and functionally characterized, such as hyaluronidases, allergen factor, serpin, TCTP and knottins (ICK peptides). All these toxins were produced as recombinant molecules and are biologically active molecules that can be used as tools for the potential development of chemical candidates to tackle many medical and biological threats, acting, for instance, as antitumoral, insecticides, analgesic, antigens for allergy tests and biochemical reagents for cell studies. In addition, these recombinant toxins may be useful to develop a rational therapy for loxoscelism. This review summarizes the main candidates for the development of drugs and biotechnological inputs that have been described in Brown spider venoms.

Description of a serpin toxin in Loxosceles (Brown spider) venoms: Cloning, expression in baculovirus-infected insect cells and functional characterization

Several classes of toxins are present in the venom of Brown spiders (Loxosceles genus), some of them are highly expressed and others are less expressed. In this work, we aimed to clone the sequence of a little expressed novel toxin from Loxosceles venom identified as a serine protease inhibitor (serpin), as well as to express and characterize its biochemical and biological properties. It was named LSPILT, derived from Loxoscelesserine protease inhibitor-like toxin. Multiple alignment analysis revealed high identity between LSPILT and other serpin molecules from spiders and crab. LSPILT was produced in baculovirus-infected insect cells, resulting in a 46-kDa protein fused to a His-tag. Immunological assays showed epitopes in LSPILT that resemble native venom toxins of Loxosceles spiders. The inhibitory activity of LSPILT on trypsin was found both by reverse zymography and fluorescent gelatin-degradation assay. Additionally, LSPILT inhibited the complement-dependent lysis of Trypanosoma cruzi epimastigotes, reduced thrombin-dependent clotting and suppressed B16-F10 melanoma cells migration. Results described herein prove the existence of conserved serpin-like toxins in Loxosceles venoms. The availability of a recombinant serpin enabled the determination of its biological and biochemical properties and indicates potential applications in future studies regarding the pathophysiology of the envenoming or for biotechnological purposes.

Skin Necrosis, Diffuse Urticaria, and Cellulitis Due to Presumed Loxosceles Spider Bite

The clinical manifestations of a recluse spider bite range from local erythema to necrotic skin reactions; bites rarely lead to a systemic disease known as viscerocutaneous loxoscelism. A 29-y-old female patient was admitted to the emergency department with a wound, swelling, and pain on her left leg and a rash on her whole body as a result of a spider bite. On physical examination, a round, hard, black, irregularly shaped necrotic area was found in the bite zone on the lower posterior part of the left thigh, as were lesions in the form of erythematous papules around the area. There was a color change around the lesion, extending from posterior to medial of the thigh, and a papule on a diffuse erythematous surface on the trunk and arms. At follow-up, the necrotic area had become more apparent. After approximately 1 mo, the necrotic area was surgically debrided and a flap was formed on the necrotic tissue area. In this article, a case that was thought to be caused by a Loxosceles spider bite and which started with erythema, progressed to lymphangitis, cellulitis, and severe necrosis, and was surgically debrided, was evaluated in light of the clinical findings and previously reported cases of verified loxoscelism. In patients with a history suggestive of a bite and with these clinical findings, the diagnosis of a bite by Loxosceles spp. should be carefully considered based on clinical and epidemiologic findings.

Clinical aspects, diagnosis and management of Loxosceles spider envenomation: literature and case review

The genus Loxosceles comprises 140 species widely distributed around the world. These spiders are nocturnal, sedentary and remarkably nonaggressive, although they cause accidents in humans with wide degrees of severity, generating signs and symptoms that define the clinical condition known as loxoscelism. Its local signs and symptoms were first reported in 1872, and over the years, a large medical literature has been accumulated; unfortunately, it is not always trustworthy. Assessing the reliability of such information, we reviewed 120 case reports of loxoscelism published in 84 articles over the past 20 years. This search allowed us to gather information on the clinical aspects, diagnosis and treatment of loxoscelism, showing that the severity of these accidents has multiple degrees and that it is influenced by many factors. Thus, coupled with epidemiological and species occurrence information, this study can be a useful tool for the clinical practice of loxoscelism. It may support and provide a multidisciplinary view that should be taken into consideration when establishing the therapeutic approach in cases of Loxosceles envenomation.

Forty Years of the Description of Brown Spider Venom Phospholipases-D

Spiders of the genus Loxosceles, popularly known as Brown spiders, are considered a serious public health issue, especially in regions of hot or temperate climates, such as parts of North and South America. Although the venoms of these arachnids are complex in molecular composition, often containing proteins with distinct biochemical characteristics, the literature has primarily described a family of toxins, the Phospholipases-D (PLDs), which are highly conserved in all Loxosceles species. PLDs trigger most of the major clinical symptoms of loxoscelism i.e., dermonecrosis, thrombocytopenia, hemolysis, and acute renal failure. The key role played by PLDs in the symptomatology of loxoscelism was first described 40 years ago, when researches purified a hemolytic toxin that cleaved sphingomyelin and generated choline, and was referred to as a Sphingomyelinase-D, which was subsequently changed to Phospholipase-D when it was demonstrated that the enzyme also cleaved other cellular phospholipids. In this review, we present the information gleaned over the last 40 years about PLDs from Loxosceles venoms especially with regard to the production and characterization of recombinant isoforms. The history of obtaining these toxins is discussed, as well as their molecular organization and mechanisms of interaction with their substrates. We will address cellular biology aspects of these toxins and how they can be used in the development of drugs to address inflammatory processes and loxoscelism. Present and future aspects of loxoscelism diagnosis will be discussed, as well as their biotechnological applications and actions expected for the future in this field.

Probable cutaneous loxoscelism with mild systemic symptoms: A case report from Spain

We present a case from Valencia, Spain, of a 25-year-old woman who presented with a painful erythematous skin lesion, initially diagnosed as cellulitis. The lesion was unresponsive to antibiotic treatments and progressed into a hemorrhagic blister with necrotic ulcer formation. Posterior collection of a spider from the patient's home and expert identification of the spider as Loxosceles rufescens was achieved, establishing the diagnosis of probable cutaneous loxoscelism. Symptomatic treatment, general wound care and ultimately surgery, resulted in complete recovery with minor residual scarring. This case illustrates some of the difficulties encountered in the diagnosis and treatment of loxoscelism and adds to the increasing reports of loxoscelism in the Mediterranean Basin.

Defining the complex phenotype of severe systemic loxoscelism using a large electronic health record cohort

Objective

Systemic loxoscelism is a rare illness resulting from the bite of the recluse spider and, in its most severe form, can lead to widespread hemolysis, coagulopathy, and death. We aim to describe the clinical features and outcomes of the largest known cohort of individuals with moderate to severe loxoscelism.

Methods

We performed a retrospective, cross sectional study from January 1, 1995, to December 31, 2015, at a tertiary-care academic medical center, to determine individuals with clinical records consistent with moderate to severe loxoscelism. Age-, sex-, and race-matched controls were compared. Demographics, clinical characteristics, laboratory measures, and outcomes of individuals with loxoscelism are described. Case and control groups were compared with descriptive statistics and phenome-wide association study (PheWAS).

Results

During the time period, 57 individuals were identified as having moderate to severe loxoscelism. Of these, only 33% had an antecedent spider bite documented. Median age of individuals diagnosed with moderate to severe loxoscelism was 14 years old (IQR 9.0–24.0 years). PheWAS confirmed associations of systemic loxoscelism with 29 other phenotypes, e.g., rash, hemolytic anemia, and sepsis. Hemoglobin level dropped an average of 3.1 g/dL over an average of 2.0 days (IQR 2.0–6.0). Lactate dehydrogenase and total bilirubin levels were on average over two times their upper limit of normal values. Eighteen individuals of 32 tested had a positive direct antiglobulin (Coombs’) test. Mortality was 3.5% (2/57 individuals).

Conclusion

Systemic loxoscelism is a rare but devastating process with only a minority of patients recalling the toxic exposure; hemolysis reaches a peak at 2 days after admission, with some cases taking more than a week before recovery. In endemic areas, suspicion for systemic loxoscelism should be high in individuals, especially children and younger adults, presenting with a cutaneous ulcer and hemolysis or coagulopathy, even in the absence of a bite exposure history.

Rare case of dermonecrosis caused by a recluse spider bite in Europe

Spider poisoning is rare in Europe, with very few reported cases in the literature. Recluse spider (genus Loxosceles) bites may lead to cutaneous and systemic manifestations known as loxoscelism. We report the second known case of spider bite poisoning in Malta caused by Loxosceles rufescens (Mediterranean recluse spider). A young adult female presented with localised erythema and pain on her left thigh after a witnessed spider bite. Over a few days, the area developed features of dermonecrosis together with systemic symptoms, including fever, fatigue and a generalised erythematous eruption. She was managed by a multidisciplinary team and the systemic symptoms resolved within 6 days, while the skin lesion healed with scarring within 2 months. A recluse spider bite should be considered in patients with dermonecrosis. Although spider bite poisoning is uncommon in Europe, it is important to diagnose and manage it appropriately since it could lead to potentially serious sequelae.

Extreme pain from brown recluse spider bites: model for cytokine-driven pain

IMPORTANCE

Bites from the brown recluse spider (BRS) can cause extreme pain. We propose cytokine release as a cause of the discomfort and a central mechanism through glial cell upregulation to explain measured pain levels and time course.

OBSERVATIONS

Twenty-three BRS bites were scored at a probable or documented level clinically, and an enzyme-linked immunosorbent assay was used to confirm the presence of BRS venom. The mean (SD) pain level in these cases 24 hours after the spider bite was severe: 6.74 (2.75) on a scale of 0 to 10. Narcotics may be needed to provide relief in some cases. The difference in pain level by anatomic region was not significant. Escalation observed in 22 of 23 cases, increasing from low/none to extreme within 24 hours, is consistent with a cytokine pain pattern, in which pain increases concomitantly with a temporal increase of inflammatory cytokines.

CONCLUSIONS AND RELEVANCE

These findings in BRS bites support the hypothesis of cytokine release in inflammatory pain. A larger series is needed to confirm the findings reported here. The extreme pain from many BRS bites motivates us to find better prevention and treatment techniques.

Surgical treatment of a brown recluse spider bite: a case study and literature review

Spider bite envenomation can cause local, constitutional, and/or systemic symptoms. The present case study reports on 5 years of follow-up for a "probable" brown recluse spider bite of the foot and ankle that was refractory to conservative treatment and was subsequently treated with surgery. The present case study reports the atypical occurrence of long-term peripheral neuropathy after necrotic arachnidism induced by "probable" brown recluse (Loxosceles recluse) envenomation, in a 46-year-old male. The state of published data suggests to minimize inflammation and tissue necrosis, prevent bacterial superinfection, and control pain levels. For patients with long-term peripheral neuropathy refractory to conservative therapy, surgical intervention may further improve their symptoms.

A case of Spider bite localized to the eyelid

Loxosceles Spiders have a worldwide distribution and are considered one of the most medically important groups of Spiders. The venom from Spiders of the genus Loxosceles, the most famous being Loxosceles reclusa (brown recluse Spider), can promote severe local and systemic damages. This report describes a girl presenting with a Spider bite over her right upper eyelid.

Lysophosphatidic acid directly activates TRPV1 through a C-terminal binding site

Since 1992, there has been growing evidence that the bioactive phospholipid lysophosphatidic acid (LPA), whose amounts are increased upon tissue injury, activates primary nociceptors resulting in neuropathic pain. The TRPV1 ion channel is expressed in primary afferent nociceptors and is activated by physical and chemical stimuli. Here we show that in control mice LPA produces acute pain-like behaviors, which are substantially reduced in Trpv1-null animals. Our data also demonstrate that LPA activates TRPV1 through a unique mechanism that is independent of G protein-coupled receptors, contrary to what has been widely shown for other ion channels, by directly interacting with the C terminus of the channel. We conclude that TRPV1 is a direct molecular target of the pain-producing molecule LPA and that this constitutes, to our knowledge, the first example of LPA binding directly to an ion channel to acutely regulate its function.

Two new phospholipase D isoforms of Loxosceles laeta: cloning, heterologous expression, functional characterization, and potential biotechnological application

Toxin phospholipases-D present in the venom of Loxosceles spiders is the principal responsible for local and systemic effects observed in the loxoscelism. In this study, we describe the cloning, expression, functional evaluation, and potential biotechnological application of cDNAs, which code for two new phospholipase D isoforms, LIPLD1 and LIPLD2, of the spider Loxosceles laeta. The recombinant protein rLIPLD1 had hydrolytic activity on sphingomyelin and in vitro hemolytic activity on human red blood cells, whereas rLIPLD2 was inactive. The purified recombinant proteins and the venom are recognized by polyclonal anti-rLIPLD1 and rLIPLD2 sera produced in animals and conferred immunoprotection against the venom. These new isoforms reinforce the importance of the multigene family of phospholipases-D present in Loxosceles spiders. A highly immunogenic inactive isoform such as rLIPLD2 raises important expectation for its use as a potential immunogenic inducer of the immunoprotective response to the toxic action of the venom of Loxosceles laeta.

Structure of a novel class II phospholipase D: catalytic cleft is modified by a disulphide bridge

Phospholipases D (PLDs) are principally responsible for the local and systemic effects of Loxosceles envenomation including dermonecrosis and hemolysis. Despite their clinical relevance in loxoscelism, to date, only the SMase I from Loxosceles laeta, a class I member, has been structurally characterized. The crystal structure of a class II member from Loxosceles intermedia venom has been determined at 1.7Å resolution. Structural comparison to the class I member showed that the presence of an additional disulphide bridge which links the catalytic loop to the flexible loop significantly changes the volume and shape of the catalytic cleft. An examination of the crystal structures of PLD homologues in the presence of low molecular weight compounds at their active sites suggests the existence of a ligand-dependent rotamer conformation of the highly conserved residue Trp230 (equivalent to Trp192 in the glycerophosphodiester phosphodiesterase from Thermus thermophofilus, PDB code: 1VD6) indicating its role in substrate binding in both enzymes. Sequence and structural analyses suggest that the reduced sphingomyelinase activity observed in some class IIb PLDs is probably due to point mutations which lead to a different substrate preference.

[Necrotic arachnidism in the south of France: two clinical cases of loxoscelism]

BACKGROUND

loxosceles spiders are found throughout the world and are responsible for numerous cases of envenomation in America and Southern Europe. We describe, to our knowledge for the first time in France, two clinical cases of cutaneous loxoscelism.

CASE REPORT

two cases of skin necrosis arising after supposed spider bites were grouped together because of their similar clinical presentation: an initial painless bite and rapid development of an inflammatory and painful cutaneous lesion with a central hemorrhagic bulla surrounded by a perimeter of blanched skin (the "red, white, and blue" sign). The outcome in both cases was deep skin necrosis and chronic ulceration requiring surgical treatment.

DISCUSSION

loxoscelism can result in dermonecrosis. Although our cases were not documented by capture of the spider, the diagnosis of cutaneous loxoscelism was supported by the characteristic appearance of the lesion, a typical clinical course, elimination of differential diagnoses, and the confirmed presence of Loxosceles rufescens in the region.

CONCLUSION

loxoscelism can occur in the south of France and although rare, must be considered in this region as a possible cause of skin necrosis.

Loxoscelism and Negative Pressure Wound Therapy (Vacuum-Assisted Closure): A Clinical Case Series

Brown recluse spider (Loxosceles sp) bites continue to be a significant challenge to manage clinically. Sequelae from these lesions range from chronic necrotic ulcers that persist for months to an acute life-threatening course of sepsis. Negative pressure wound therapy using vacuum-assisted closure (VAC) has been described for use in both acute and chronic wounds. We present a novel application for the use of this therapy in a retrospective review of eight clinical cases treated with the VAC.

An in vivo protective response against toxic effects of the dermonecrotic protein from Loxosceles intermedia spider venom elicited by synthetic epitopes

Loxoscelism is a necrotic-hemolytic syndrome caused by bites of brown spiders belonging to the genus Loxosceles. Many approaches for the treatment of Loxosceles poisoning have already been proposed, among which administration of specific antivenom is thought to be the more specific. We have evaluated the use of peptides as immunogen to raise in rabbits an antibody response that could protect animals from a challenge by the Loxtox isoform LiD1, one of the main toxic component of Loxosceles intermedia venom. Six antigenic regions of LiD1 were mapped by using the SPOT method. The corresponding peptides were further chemically synthesized, mixed, and used as immunogens in rabbits. Control animal received recombinant LiD1 alone or together with peptides. We found that the rabbit antibody response to peptides was cross-reactive with LiD1, although only one peptide from the mix of six was immunogenic. The dermonecrotic, hemorrhagic and oedema forming activities induced by LiD1 in naïve rabbits were inhibited by 82%, 35% and 35% respectively, by preincubation of LiD1 with anti-peptide antibodies prepared from immunized rabbits. Animals that were immunized with peptides or LiD1r, were found to be protected from the dermonecrotic, hemorrhagic and oedema forming activities induced by a challenge with LiD1. The protection conferred by peptides was, however, lower than that provided by the peptide protein combination or by the full-length protein. These results encourage us in the utilization of synthetic peptides for therapeutic serum development or vaccination approaches.

Biotechnological applications of brown spider (Loxosceles genus) venom toxins

Loxoscelism (the term used to define accidents by the bite of brown spiders) has been reported worldwide. Clinical manifestations following brown spider bites are frequently associated with skin degeneration, a massive inflammatory response at the injured region, intravascular hemolysis, platelet aggregation causing thrombocytopenia and renal disturbances. The mechanisms by which the venom exerts its noxious effects are currently under investigation. The whole venom is a complex mixture of toxins enriched with low molecular mass proteins in the range of 5-40 kDa. Toxins including alkaline phosphatase, hyaluronidase, metalloproteases (astacin-like proteases), low molecular mass (5.6-7.9 kDa) insecticidal peptides and phospholipases-D (dermonecrotic toxins) have been identified in the venom. The purpose of the present review is to describe biotechnological applications of whole venom or some toxins, with especial emphasis upon molecular biology findings obtained in the last years.

Generalized vasculitic exanthem following Loxosceles reclusa envenomation

Brown recluse spider bites (BRSB) cause a myriad of reactions ranging from local necrosis to potentially lethal systemic involvement. Envenomation may induce a generalized exanthem known clinically but not described histologically. We report a 49-year-old female who developed a generalized exanthem 24 hours after BRSB. The histopathology demonstrated a necrotizing vasculitis similar to that seen at an envenomation site but without epidermal necrosis. Loxoscelism should be considered in patients residing in endemic areas who present with a vasculitic exanthem.

Diagnosis of loxoscelism in a child confirmed with an enzyme-linked immunosorbent assay and noninvasive tissue sampling

BACKGROUND

Confirmation of mild bites caused by Loxosceles reclusa with swab testing has not been previously documented, to our knowledge.

METHODS

We report a case using an enzyme-linked immunosorbent assay (ELISA) test.

RESULTS

A lesion lacking necrosis or other specific signs of loxoscelism was confirmed by identification of the Loxosceles venom and further confirmed by identification of a spider found in the patient's bed.

LIMITATIONS

This is a pilot single-case report for this enzyme-linked immunosorbent assay test.

CONCLUSIONS

A sensitive and specific enzyme-linked immunosorbent assay designed to detect Loxosceles venom, using a specimen obtained by swabbing the lesion, can aid in diagnosis of loxoscelism.

The efficacy of antivenom in loxoscelism treatment

Loxoscelism or brown spider envenomation is the most important form of araneism in some countries and constitutes the third cause of accidents by venomous animals in Brazil. The treatment of Loxosceles bites is still controversial, with a variety of interventions proposed and tried, such as antivenom. The majority of clinical studies demonstrate a significant delay between a spider's bite and presentation for treatment, and this delay is thought to lead to an ineffective administration of a specific antivenom. Even in Brazil, where the antivenom therapy has been indicated more frequently than in other countries, there are still doubts about its real capacity to neutralize local and systemic effects of the envenomation and the ideal period for its administration. Thus, various studies in animal models have tried to correlate the time of envenomation with the application of the antivenom and the permanence of the venom in circulation or in dermonecrotic lesions. The purpose of this study was to evaluate the use of antivenom in loxoscelism treatment and to systematize the results of studies in animals and humans available in the last 30 years, making possible a more critical analysis of the efficacy of the antivenom or its therapeutic value in bites by spiders of the genus Loxosceles.

Management of Hard-to-Heal Wounds

Some wounds do not heal normally and present the practitioner with a challenge. These can be thought of as hard-to-heal wounds. There are numerous causes of such wounds, and when they occur, the veterinarian should consider all factors associated with the wound. When diagnostic tests are indicated, they should be performed. Finally, appropriate measures should be taken to correct the underlying cause of the hard-to-heal wound.