Necrotic ulcers caused by Loxosceles rufescens bites: a report of seven patients and scanning electron microscopy of the spider.

Loxosceles rufescens is a spider that may bite humans. To describe the clinical manifestations and treatment of patients with bites caused by L. rufescens, and present scanning electron microscopy of the spider. Twelve patients are described, seven with a confirmed aetiological diagnosis as a sample of the spider was captured. In one case, scanning electron microscopy of the spider was performed. Seven patients presented with a single necrotic ulcer of varying morphology, with a purulent-necrotic bed, located on the neck (one patient), buttock (one patient), thigh (one patient), legs (three patients) and foot (one patient). All patients complained of burning and pain. No systemic symptoms were observed. All patients were treated with sodium hypochlorite solution packs, an equine catalase gel, and polyhexamethylene biguanide cream. Oral analgesics were added. In one patient, oral prednisone was prescribed. Two patients with bacterial superinfections were treated with i.v. piperacillin/tazobactam or i.m. ceftriaxone. All patients recovered within eight weeks, however, a scar developed in five of six patients. The sequence of cutaneous manifestations due to L. rufescens bites is typical. At first, erythema and oedema forms, followed by a vesicle, blister or pustule and, finally, an eschar and scar. Systemic symptoms and signs are rare. To consider this spider as an aetiological agent of necrotic ulcers, it is necessary to capture a sample of the spider, dead or alive, which should then be identified by an expert. Corticosteroids, antibiotics and analgesics are frequently used. Surgery is often necessary.

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

DECLARATION OF INTEREST: The authors have no conflicts of interest.

Systemic loxoscelism leading to autoimmune haemolytic anaemia in a healthy young adult.

The brown recluse spider (Loxosceles reclusa) is endemic to the southcentral Midwest and the Southern United States. A bite from a brown recluse spider may result in symptoms that range from local skin necrosis to systemic complications such as acute haemolytic anaemia, disseminated intravascular coagulopathy, rhabdomyolysis and death. Although rare, systemic loxoscelism is a clinical diagnosis of exclusion that should be considered in a patient with acute autoimmune haemolytic anaemia. We describe a case of a young man with autoimmune haemolytic anaemia secondary to systemic loxoscelism successfully treated with intravenous immunoglobulin and steroids.

Discovery of broadly-neutralizing antibodies against brown recluse spider and Gadim scorpion sphingomyelinases using consensus toxins as antigens.

Broadly-neutralizing monoclonal antibodies are becoming increasingly important tools for treating infectious diseases and animal envenomings. However, designing and developing broadly-neutralizing antibodies can be cumbersome using traditional low-throughput iterative protein engineering methods. Here, we present a new high-throughput approach for the standardized discovery of broadly-neutralizing monoclonal antibodies relying on phage display technology and consensus antigens representing average sequences of related proteins. We showcase the utility of this approach by applying it to toxic sphingomyelinases from the venoms of species from very distant orders of the animal kingdom, the recluse spider and Gadim scorpion. First, we designed a consensus sphingomyelinase and performed three rounds of phage display selection, followed by DELFIA-based screening and ranking, and benchmarked this to a similar campaign involving cross-panning against recombinant versions of the native toxins. Second, we identified two scFvs that not only bind the consensus toxins, but which can also neutralize sphingomyelinase activity of native whole venom in vitro. Finally, we conclude that the phage display campaign involving the use of the consensus toxin was more successful in yielding cross-neutralizing scFvs than the phage display campaign involving cross-panning.

Aranhas de interesse médico no Brasil / Spiders of medical interest in Brazil

O documento apresenta informações sobre aranhas de importância médica no Brasil. Descreve a estrutura externa das aranhas e destaca três gêneros de importância em saúde pública: aranha-marrom (Loxosceles), aranha-armadeira ou macaca (Phoneutria) e viúva-negra (Latrodectus). Traz imagens dessas espécies e lista sinais, sintomas e tratamento para acidentes com elas. Apresenta dados de série histórica de acidentes por aranhas no Brasil e Tocantins entre 2000-2022. Por fim, traz recomendações sobre prevenção e primeiro atendimento para acidentes com aranhas.

The document provides information on medically significant spiders in Brazil. It describes the external structure of spiders and highlights three genera of public health importance: brown recluse spider (Loxosceles), wandering spider or macaque spider (Phoneutria), and black widow spider (Latrodectus). It includes images of these species and lists signs, symptoms, and treatment for accidents involving them. It presents historical data on spider-related accidents in Brazil and Tocantins between 2000-2022. Finally, it provides recommendations for prevention and initial first aid for spider bites.

El documento proporciona información sobre arañas de importancia médica en Brasil. Describe la estructura externa de las arañas y destaca tres géneros de importancia para la salud pública: la araña de rincón (Loxosceles), la araña errante o araña mono (Phoneutria) y la viuda negra (Latrodectus). Incluye imágenes de estas especies y enumera los signos, síntomas y tratamiento para accidentes con ellas. Presenta datos históricos sobre accidentes relacionados con arañas en Brasil y Tocantins entre 2000 y 2022. Por último, proporciona recomendaciones para la prevención y la atención de primeros auxilios en caso de picaduras de araña.

Massive dermal ulcerative lesions due to brown recluse spider bite: a rare case report and review of literature.

A brown recluse spider (BRS) bite is challenging to confirm, but may be clinically diagnosed by considering the location, the season of the year, and the clinical manifestations. Here, the case of a 26-year-old male who presented after an insect bite with a skin lesion, bruising, severe swelling, and diffuse blisters on the right lower extremity after three days, is described. Following clinical examination, patient history assessment, and consideration of other relevant factors, the patient received a differential diagnosis of necrotizing fasciitis caused by BRS bite. Although spider bite poisoning is rare, proper diagnosis and management are important because, in some cases, the outcomes may be devastating.

Severe complications in a 25-year-old male after brown recluse spider bite treated by therapeutic plasma exchange: A case report and review of other case studies.

Although in the majority of patients (90%), the bite wound of brown recluse spider resolves spontaneously, some patients may experience a severe reaction requiring hospitalization. A 25-year-old male developed severe hemolytic anemia, jaundice, and other complications following a brown recluse spider bite on his posterior right thigh. He was treated with methylprednisolone, antibiotics, and red blood cells (RBCs) transfusion without response. Therapeutic plasma exchange (TPE) was added to the treatment regimen, and his hemoglobin (Hb) was eventually stabilized, leading to significant clinical improvement. The beneficial effect of TPE in the current case was compared to three other reported cases. We recommend close monitoring of Hb levels in patients with systemic loxoscelism during the first week after brown recluse spider bite and early implementation of TPE in the management of severe acute hemolysis when patients do not respond to usual treatment modalities and RBC transfusion.

Enxerto em ilha para tratamento de lesão dermonecrótica em um cão atribuída a aracnidismo por Loxosceles / Island graft for the treatment of a dermonecrotic lesion in a dog attributed to loxosceles arachnidism

A picada da aranha do gênero Loxosceles, popularmente conhecidas como "aranha marrom", pode levar a uma extensa lesão dermonecrótica de difícil cicatrização e fechamento, sendo um desafio o seu tratamento. Os enxertos cutâneos são segmentos livres e independentes de pele e epiderme transferidos para um local receptor distante, normalmente utilizados para perda tecidual extensa de membros e grandes falhas dermatológicas no tronco. No presente trabalho relata-se o caso de um canino, sem raça definida, macho, 4 anos de idade, com 13,3 kg, apresentando uma lesão extensa de pele com evolução para necrose dérmica e perda substancial de tecido cutâneo, sendo associada a picada por Loxosceles spp, com base em dados da anamnese, sinais clínicos e evolução da lesão, além de ser descartado outras causas de dermonecrose como aplicação de medicamentos no subcutâneo, lesão térmica ou química. O diagnóstico de loxoscelismo raramente é baseado na identificação da aranha, tendo em vista que os tutores normalmente não observam o momento do acidente uma vez que a picada é indolor. Foi utilizado técnica de cirurgia reconstrutiva por meio de enxertos em ilha devido à extensa lesão tecidual sem possibilidade de fechamento primário com justaposição de bordas. A evolução clínica foi positiva e o animal apresentou recuperação completa após 66 dias de tratamento, sendo necessários dois procedimentos cirúrgicos de desbridamento de tecido necrótico e aproximação de bordas, associado a curativos frequentes utilizando membrana de alginato e hidrocoloide em momentos diferentes das fases de cicatrização, a fim de estimular a granulação do tecido e evitar a infecção do local. Esses cuidados foram tomados para assegurar que a região estivesse apta a receber a enxertia de pele como procedimento cirúrgico final e que a cicatrização ocorresse de forma mais rápida do que por segunda intenção, reconhecidamente lenta quando ocorre de forma espontânea, levando o paciente a maior tempo de desconforto, com alto risco de tração tecidual e contaminação local. No presente relato a cirurgia reconstrutiva se mostrou uma boa alternativa no tratamento de ferida extensa e com isso espera-se contribuir para a divulgação do uso das diversas técnicas reconstrutivas visando acelerar o processo de cicatrização e possibilitar um bom resultado final para os pacientes.

The bite of the spider of the genus Loxosceles, popularly known as the "brown spider", can lead to an extensive dermonecrotic lesion that is difficult to heal and close, making its treatment a challenge. Skin grafts are free, independent segments of skin and epidermis transferred to a distant recipient site, typically used for extensive tissue loss from limbs and large dermatological defects on the trunk. This paper reports the case of a canine, mixed breed, male, 4 years old, weighing 13.3 kg, presenting with an extensive skin lesion that progressed to dermal necrosis and substantial loss of skin tissue, associated with bite by Loxosceles spp, based on data from the anamnesis, clinical signs and evolution of the lesion, in addition to ruling out other causes of dermonecrosis such as application of subcutaneous drugs, thermal or chemical injury. The diagnosis of loxoscelism is rarely based on the identification of the spider, considering that owners usually do not observe the moment of the accident, since the bite is painless. A reconstructive surgery technique was used using island grafts due to extensive tissue damage without the possibility of primary closure with juxtaposition of edges. The clinical evolution was positive and the animal presented complete recovery after 66 days of treatment, requiring two surgical procedures for debridement of necrotic tissue and approximation of edges, associated with frequent dressings using alginate membrane and hydrocolloid at different times of the healing phases, in order to stimulate tissue granulation and avoid local infection to be able to receive skin grafting as a final surgical procedure, favoring faster healing of the lesion, since healing by second intention takes longer to occur than spontaneously, leading the patient to greater discomfort with a high risk of tissue traction and local contamination when care is not performed properly. In this case, reconstructive surgery proved to be a good alternative in the treatment of extensive wounds.

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.

Primer registro de un caso de loxoscelismo cutáneo ocasionado por mordedura de araña violinista (Loxosceles yucatana) en Yucatán, México / First record of a case of cutaneous loxoscelism caused by violin spider (Loxosceles yucatana) bite in Yucatan, Mexico

El loxoscelismo es ocasionado cuando el veneno dermonecrótico producido por las arañas del género Loxosceles, conocidas como «arañas violinistas», ingresa al organismo de una persona a través de su mordida. En México ocurre un subregistro de los casos de loxoscelismo por la ausencia de pruebas de laboratorio para su diagnóstico y la dificultad del cuadro clínico. El objetivo de este trabajo es describir un caso de loxoscelismo cutáneo ocasionado por mordedura de Loxosceles yucatana en un residente de Yucatán, México. El loxoscelismo cutáneo es el tipo más frecuente y menos severo. El presente caso se diagnosticó por medio de la sintomatología registrada en la historia clínica, la lesión inicial y la identificación de arañas L. yucatana. Este trabajo representa la primera descripción de un caso de loxoscelismo cutáneo con resolución favorable en Yucatán.

Loxoscelism occurs when the dermonecrotic venom produced by spiders of the genus Loxosceles, known as "violin spiders," enters a person's organism through their bite. In Mexico there is an underreporting of loxoscelism cases due to the absence of laboratory tests for its diagnosis and the complexity of the clinical picture. The aim of this paper is to describe a case of cutaneous loxoscelism caused by the bite of Loxosceles yucatana in a resident of Yucatan, Mexico. Cutaneous loxoscelism is the most frequent and less severe type. This case was diagnosed by means of the symptomatology registered in the medical records, the initial lesion, and the identification of L. yucatana spiders. This study represents the first description of a case of cutaneous loxoscelism with favorable outcome in Yucatan.

Brown spider (Loxosceles sp.) bite and COVID-19: A case report.

We present the case of a 32-year-old male patient hospitalized during the COVID-19 pandemic because of a Brown spider bite on his lower lip. The Brown spider accident occurred in southern Brazil; at hospital admission, the patient presented on his lip: edema, pustules, necrotic regions, and ulcerations. The patient complained of lower back pain, fever and dyspnea. Laboratory tests showed monocytosis, leukocytosis, neutrophilia, increased D-dimer levels, C-reactive protein, glutamate-pyruvate transaminase, delta bilirubin, creatine phosphokinase, procalcitonin, and fibrinogen. The patient was hospitalized and a multi-professional team carried out the treatment. The medical team diagnosed loxoscelism with moderate changes. The dentist treated the oral cavity. The patient began to develop nausea, vomiting, and desaturation episodes during hospitalization. A computed tomography of the chest was performed, which showed signs of viral infection. The RT-PCR test for COVID-19 was positive. The systemic conditions worsened (renal dysfunction, systemic inflammatory response, pulmonary complications). This condition may have resulted from the association of the two diseases (loxoscelism and COVID-19), leading to the patient's death. This case illustrates the difficulties and risks in treating patients with venomous animal accidents during the pandemic, and the importance of a multi-professional team in treating such cases.

Diethyl Azelate for the Treatment of Brown Recluse Spider Bite, a Neglected Orphan Indication.

BACKGROUND/AIM: Brown recluse spider bite releases hemolytic and cytotoxic phospholipase D to the wound that may cause necrosis or even death. We examined diethyl azelate (DEA), a plasma membrane fluidizer with a broad range of immunomodulatory activities, as a potential treatment for the brown recluse spider bite. MATERIALS AND METHODS: Topical DEA was used in emergency to treat brown recluse spider bites in a human subject. We subsequently evaluated the effects of DEA on hemolysis induced by the brown recluse spider venom, recluse recombinant phospholipase D (rPLD), and venoms from honey bee and moccasin snake, and on phospholipase A2 activity in the bee and snake venoms and in human urine. RESULTS: Topical DEA resolved the consequences of human brown recluse spider envenomation in two weeks. In vitro, DEA inhibited hemolysis caused by the brown recluse spider venom and rPLD and suppressed phospholipase A2 activity in a dose-dependent manner. CONCLUSION: DEA is a promising novel therapy for the brown recluse spider bite and perhaps even unrelated envenomations involving PLDs.

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.

First record of a case of cutaneous loxoscelism caused by violin spider (Loxosceles yucatana) bite in Yucatan, Mexico. / Primer registro de un caso de loxoscelismo cutáneo ocasionado por mordedura de araña violinista (Loxosceles yucatana) en Yucatán, México.

Loxoscelism occurs when the dermonecrotic venom produced by spiders of the genus Loxosceles, known as "violin spiders," enters a person's organism through their bite. In Mexico there is an underreporting of loxoscelism cases due to the absence of laboratory tests for its diagnosis and the complexity of the clinical picture. The aim of this paper is to describe a case of cutaneous loxoscelism caused by the bite of Loxosceles yucatana in a resident of Yucatan, Mexico. Cutaneous loxoscelism is the most frequent and less severe type. This case was diagnosed by means of the symptomatology registered in the medical records, the initial lesion, and the identification of L. yucatana spiders. This study represents the first description of a case of cutaneous loxoscelism with favorable outcome in Yucatan.

El loxoscelismo es ocasionado cuando el veneno dermonecrótico producido por las arañas del género Loxosceles, conocidas como «arañas violinistas¼, ingresa al organismo de una persona a través de su mordida. En México ocurre un subregistro de los casos de loxoscelismo por la ausencia de pruebas de laboratorio para su diagnóstico y la dificultad del cuadro clínico. El objetivo de este trabajo es describir un caso de loxoscelismo cutáneo ocasionado por mordedura de Loxosceles yucatana en un residente de Yucatán, México. El loxoscelismo cutáneo es el tipo más frecuente y menos severo. El presente caso se diagnosticó por medio de la sintomatología registrada en la historia clínica, la lesión inicial y la identificación de arañas L. yucatana. Este trabajo representa la primera descripción de un caso de loxoscelismo cutáneo con resolución favorable en Yucatán.

A protective vaccine against the toxic activities following Brown spider accidents based on recombinant mutated phospholipases D as antigens.

Accidents involving Brown spiders are reported throughout the world. In the venom, the major toxins involved in the deleterious effects are phospholipases D (PLDs). In this work, recombinant mutated phospholipases D from three endemic species medically relevant in South America (Loxosceles intermedia, L. laeta and L. gaucho) were tested as antigens in a vaccination protocol. In such isoforms, key amino acid residues involved in catalysis, magnesium-ion coordination, and binding to substrates were replaced by Alanine (H12A-H47A, E32A-D34A and W230A). These mutations eliminated the phospholipase activity and reduced the generation of skin necrosis and edema to residual levels. Molecular modeling of mutated isoforms indicated that the three-dimensional structures, topologies, and surface charges did not undergo significant changes. Mutated isoforms were recognized by sera against the crude venoms. Vaccination protocols in rabbits using mutated isoforms generated a serum that recognized the native PLDs of crude venoms and neutralized dermonecrosis and edema induced by L. intermedia venom. Vaccination of mice prevented the lethal effects of L. intermedia crude venom. Furthermore, vaccination of rabbits prevented the cutaneous lesion triggered by the three venoms. These results indicate a great potential for mutated recombinant PLDs to be employed as antigens in developing protective vaccines for Loxoscelism.

Picadura de la araña reclusa / Bite of recluse spider

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