International Journal of Academic Medicine

IMAGES IN ACADEMIC MEDICINE
Year
: 2016  |  Volume : 2  |  Issue : 2  |  Page : 256--259

Classic brown recluse spider bite


Mark William Fegley1, Rodrigo Duarte-Chavez2, Lauren E Stone3, Sudip Nanda2,  
1 Department of Family Medicine, St. Luke's University Health Network, PA, USA
2 Department of Internal Medicine, St. Luke's University Health Network, PA, USA
3 Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA

Correspondence Address:
Sudip Nanda
Department of Internal Medicine, St. Luke's University Hospital Network, 801 Ostrum Street, Bethlehem, PA 18015
USA

Abstract

A 58-year-old female presented with leg paresthesia and rash. On presentation, the rash was most consistent with cellulitis and cephalexin was started. The next day vesicles appeared which were presumed to be shingles and acyclovir was started. They evolved into a fully necrotic lesion on day 4 and had the classic presentation of a brown recluse spider bite. Bite marks were missed at presentation. Brown recluse spider bites are commonly misdiagnosed 80% of the time. Brown recluse venom contains a variety of toxins which can lead to skin necrosis (37% of patients) that occurs via an unknown mechanism dependent on host neutrophils. Skin changes progress over 12–36 h and necrosis develops within several days. Treatment recommendations call for exclusion of other diagnoses and conservative management with local wound care, tetanus prophylaxis, and debridement. Other forms of treatment should be avoided. Our patient was treated with a skin graft with good results. The following core competencies are addressed in this article: Patient care and medical knowledge.



How to cite this article:
Fegley MW, Duarte-Chavez R, Stone LE, Nanda S. Classic brown recluse spider bite.Int J Acad Med 2016;2:256-259


How to cite this URL:
Fegley MW, Duarte-Chavez R, Stone LE, Nanda S. Classic brown recluse spider bite. Int J Acad Med [serial online] 2016 [cited 2021 Jan 23 ];2:256-259
Available from: https://www.ijam-web.org/text.asp?2016/2/2/256/196867


Full Text



 Introduction



A 58-year-old female presented with leg paresthesia and rash. Suspecting shingles, she was started on acyclovir. The lesion quickly evolved into a fully necrotic lesion on day 4 and had the classic presentation of a brown recluse spider bite. Brown recluse spider bites are misdiagnosed 80% of the time. Initial treatment for brown recluse spider bites remains controversial.

 Case Report



A 58-year-old female presented to our emergency department (ED) with sudden leg pain and rash starting 12 h ago [Figure 1]a. The rash at this time was most consistent with cellulitis and treated with cephalexin. She returned to the ED 36 h later with raised vesicular lesions and was treated with acyclovir for presumed shingles [Figure 1]b. Skin necrosis developed on the day 4, and patient was diagnosed with a brown recluse spider bite and tetanus prophylaxis was updated [Figure 1]c. The patient underwent debridement of necrotic skin and no further pharmacologic treatment was given [Figure 1]d. She had a skin graft 4 weeks after the bite and had a good result at follow-up 5 weeks after procedure [Figure 1]e and [Figure 1]f.{Figure 1}

 Discussion



Brown recluse (Loxosceles reclusa) spiders are known to cause necrotic skin lesions. The spiders are native to the South-Central and the Southeastern United States. Brown recluse bites outside of the native region are rare, often with <1 bite per year in a given state, but do exists.[1] Cases outside of the native region are proposed to occur via transport of household goods.[2] Because the spiders can live for up to 6 months without food and water, bites are often reported during holidays when items such as decorations are uncovered from storage.[3]

The exact pathogenesis of the brown recluse spider has been elusive. There are nine different proteins associated with the brown recluse spider venom, the most important of which is thought to be the enzyme, sphingomyelinase D.[4] The enzyme is toxic to many cells including endothelial cells, platelets, and erythrocytes, but the most important interaction occurs with inappropriate host-dependent neutrophil activation and cytokine release, specifically interleukin 8.[4] Interestingly, direct toxin interaction with neutrophil causes inhibition.[4]

The activation of the neutrophils occurs via a downstream effect of the toxin.[4] A subsequent study, in support of the original neutrophil hypothesis, reveals that spider venom causes endothelial cells to release alpha- and beta-chemokines which activate host neutrophils.[5] Another more recent study has investigated cytokines as part of the injury and pain process further providing support for the host-dependent neutrophil response hypothesis.[6] Most spider bites are relatively minor and do not evolve into tissue necrosis. The incidence of skin necrosis is estimated to be 37% and only 14% of patients become systemically ill.[7] The variable patient outcomes could be explained by variability of the host neutrophil response.

A brown recluse spider bite is a difficult diagnosis to make, leading to misdiagnosis 80% of the time.[1] The spider bites have an evolving appearance over time and a wide differential diagnosis [Table 1].[1],[3],[8],[9] These spider bites are rare and will often be missed until skin necrosis appears. Because of the rarity of the bites, the best initial treatment of a suspected bite is to treat other more common conditions in the differential diagnosis along with good follow up instructions should further skin changes occur.[1] Definitive diagnosis for brown recluse spider bite is challenging; only capture of the spider and confirmation by an expert can confirm the diagnosis.[10] There are proposed positive and negative features by Rader et al. [Table 2], helpful to confirm suspicion of the diagnosis.[10] An enzyme-linked immunosorbent assay test for spider venom exists but is not readily commercially available, and skin biopsy is unable to confirm diagnosis.[6] We arrived at our diagnosis based on the obvious bite marks in photographs, and the characteristic skin changes over several days leading to skin necrosis. Positive Rader criteria included red lesion with pale clearing, surrounding purpura in a gravity-dependent spread and no pus. Negative Rader criteria included no drainage before 1 week, no ulcer before 1 week, ulcer size, no tender lymph nodes, <2 lesions, and present for <3 months.{Table 1}{Table 2}

Proposed initial treatments include local wound care, tetanus prophylaxis, wound debridement, corticosteroids, topical nitroglycerin, antihistamines, dapsone, antivenom, hyperbaric oxygen, and electric shock [Table 3]. Local wound care, addressing tetanus prophylaxis, and debridement of necrotic tissue have a well-defined role in the treatment of brown recluse spider bites and are the standard of care. Other forms of treatment are controversial and may be harmful [Table 3].[1],8,[11],[12],[13] After the initial phase of local tissue necrosis, skin grafting can be used to assist in healing several weeks later.{Table 3}

 Conclusion



Brown recluse spider bites are rare and difficult to diagnose. Proper medical care should emphasize treating conditions that are more common than brown recluse bites such as cellulitis and shingles with close follow-up instructions. When a definitive diagnosis of the spider bite is made, typically after skin necrosis occurs, treatment should emphasize local wound care, tetanus prophylaxis, and debridement of necrotic skin tissue.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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