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Acute and recurrent skin ulceration after spider bite

Steven J Pincus, Kenneth D Winkel, Gabrielle M Hawdon and Struan K Sutherland
Med J Aust 1999; 171 (2): 99-102.
Notable Case

Acute and recurrent skin ulceration after spider bite

We reviewed the records of the Australian Venom Research Unit and The Alfred Hospital Department of Hyperbaric Medicine from January 1992 to July 1998 and found 15 cases of skin ulceration after spider bite that could be followed up with the patient and the treating physician. Fourteen patients had skin ulceration attributed to white-tailed spider bites but in only three was this confirmed. One patient had skin necrosis after a confirmed black house spider bite. Recurrent skin ulceration occurred in nine of the 15 patients.

Steven J Pincus, Kenneth D Winkel,
Gabrielle M Hawdon and Struan K Sutherland

MJA 1999; 171: 99-102
See also White

Introduction - Methods - Results - Discussion - Acknowledgements - References - Authors' details
- - More articles on Insects, bites and stings

Introduction Spider bite is the single commonest reason for inquiries to the Victorian Poisons Information Centre, with over 1300 calls recorded in 1997.1 Most people with spider bite require no specific treatment and suffer only minor symptoms, but a small number develop necrotic skin lesions associated with significant morbidity.2-4 One series reported no significant illnesses in 36 bites,5 and only seven definite cases of skin necrosis after spider bite have been published in Australia.3,4,6,7 This paucity of reports has led to debate as to the ability of Australian spiders to cause skin necrosis (necrotising arachnidism).

We performed a retrospective analysis of case records of suspected necrotising arachnidism in Australia to better define its clinical features and to compare it with loxoscelism, a well-recognised cause of skin ulceration in the Americas.

Methods Patients were identified from records of inquiries from clinicians between January 1992 and July 1998 held by the Australian Venom Research Unit and cases referred to the Hyperbaric Unit of the Alfred Hospital, Melbourne. Initial case-finding criteria were a history of spider bite with subsequent ulceration or necrosis at the bite site. Only cases in which both the patient and primary treating doctor were contactable by telephone were included (with the informed consent of both patient and doctor).

In the patient interview we asked for demographic details, the method of identification of the spider, details of ulcerative or necrotic lesions and any other related problems, treatment, outcome details and relevant past medical history. This information was confirmed with the patient's doctor, who was also asked about details of investigations, treatments and outcomes.

Results Fifteen cases were identified from more than 600 patients with skin lesions but without confirmed spider bite. In 14 cases (Box 1) the spider was said to be a white-tailed spider (Lampona species) but in only three cases was this identification confirmed. One case involved two black house or black window spiders (Badumna species; see Box 2).

All of the spider bites were to the limbs, and involved blistering, ulceration or necrosis of the skin. Thirteen were described as painful. Five patients experienced ongoing disability, and one required amputation of the hand and distal forearm. Four of the 15 patients experienced systemic symptoms (fever), and three had ulcers that were culture-positive for Staphylococcus species (one positive for Streptococcus species also). Nine patients had recurrent lesions, involving recurrent breakdown or blistering of the skin after healing, or breakdown of skin grafts used to treat non-healing ulcers.

Oral or intravenous antibiotics (including doxycycline, penicillin or flucloxacillin) were given to 14 patients. Other treatments included dressings, antihistamines, topical and oral corticosteroids, hyperbaric oxygen therapy and skin grafting.

Discussion A major difficulty in the clinical study of spider bite is accurately identifying the spiders involved. Our series included 11 cases in which a spider was witnessed to bite the patient but was not captured for identification, one case where the spider was captured and identified by a clinician, and three cases where the spider was captured and identified by an expert arachnologist. White-tailed spiders are distinctive, but in most of these cases absolute attribution to Lampona is not possible. Window spiders are relatively nondescript, and therefore less likely to be correctly identified unless captured and formally identified by an arachnologist.

Four cases of skin loss attributed to bites from Lampona have been previously reported.3,4,7 Two of these (Cases 54 and 137) are included in this study, as both patients were reported to the AustralianVenom Research Unit independently.

Several cases of bites from Badumna species have been published. These patients mostly experienced significant sickness, without skin loss.2,8 Some skin loss was reported in the case of a male black house spider bite.6 The case presented here (Box 2) is the first to link the female spider to skin necrosis.

It has been suggested that many cases of suspected necrotising arachnidism in Australia may be the result of bites from spiders of the genus Loxosceles, a group associated with necrotising arachnidism on several continents.9 While it is probable that some Australian cases of necrotising arachnidism might be attributed to this spider, it would be difficult to implicate Loxosceles in the cases reported here.

The lesions reported in this series show similarities but also significant differences from those caused by Loxosceles. As with Loxosceles, the initial bite appears to be relatively painless, with pain developing over the next 12-24 hours, accompanied by local erythema and oedema, then blister formation and ulceration.10 However, Loxosceles produces a deep ulcer, with a rolled edge and necrotic base, extending into and sometimes through subcutaneous fat to expose underlying muscle.10,11 By contrast, most ulcers reported here were superficial, being confined to the epidermis and dermis. Another important difference appears to be the site of bites that progress to significant ulceration. Significant Loxosceles lesions occur in areas of abundant subcutaneous fat, with involvement extending beyond the margins of the skin necrosis.11 The lesions reported here occurred in areas of little or no subcutaneous fat.

An infectious aetiology has been proposed for necrotising arachnidism in Australia,12 but the concept that Mycobacterium ulcerans might be such an agent13 was subsequently challenged.14Bacillus, Staphylococcus and Penicillium species have been cultured from several spider venoms, including that of a Lampona species.14 Only three of the 15 patients in our series had ulcers which grew any microorganisms, but, as 14 patients had been treated with antibiotics, infective organisms may have been cleared before cultures were prepared. However, the absence of cultured organisms and poor clinical response to antibiotic therapy seen in many patients suggests that this condition is more complex than simple skin infection.

Nine of the 15 patients in our case series had recurrent ulceration. This problem had not been reported in Australia until very recently.7 There are several American reports of lesions attributed to Loxosceles that have resulted in chronic non-healing ulcers and recurrent ulceration. These were felt to be secondary to induction of a pyoderma gangrenosum-like disease process.15 Pyoderma may follow a minor injury and may be aggravated by surgery.16 It is typically associated with systemic immune abnormalities, but up to 50% of cases are described as "idiopathic". Spider bite may act as a trigger to precipitate this condition in susceptible individuals.

Several patients in our case series had histological findings consistent with pyoderma, and surgical intervention may have been associated with a poorer outcome. Although no patient in this series received corticosteroids at the doses recommended for pyoderma, long term topical corticosteroids may have slowed progression of the lesion in case 14. Prospective study of the value of this treatment in cases of necrotising arachnidism should be considered.

Management of necrotising arachnidism remains an area of debate, and there is limited information upon which to make recommendations for the Australian situation.

At least for Loxosceles envenomations, conservative management appears to be the best primary treatment. This should include tetanus prophylaxis and routine wound care. Early ice water application to bites is recommended to counter inflammation. Initial studies proposed early excision and grafting of ulcers,11 but more recent experience suggests that this may worsen the lesion and delay healing.17

Hyperbaric oxygen therapy is gaining popularity in general wound management. Animal models have produced conflicting results on the value of this type of treatment for Loxosceles lesions.18,19 Treating ulcers attributed to Lampona bites with hyperbaric oxygen therapy appears to have a marked clinical benefit.4

We thank Mr Albert Ong, of the Pathology Department, Gladstone Base Hospital, for permission to reproduce his photograph of a patient, Dr Robert Raven and Mr Phil Lawless of the Arachnology Department of the Queensland Museum, and Ms Catriona McPhee and Dr Ken Walker of the Museum of Victoria for spider identification and photographs, and Dr Ian Miller, Director of the Hyperbaric Unit at the Alfred Hospital in Melbourne, for assistance in collecting patient information. This study would not have been possible without the assistance of the many other clinicians and patients involved. We thank the Victorian Department of Human Services, CSL Limited, BHP Community Trust and Snowy Nominees for financial support, and Dr Anna Young and Dr Tony Pennington for helpful discussion.


To address the paucity of clinical data on necrotising arachnidism the Australian Venom Research Unit, together with the Monash Medical Centre's Department of Emergency Medicine, is conducting a long term prospective study of the outcome of spider bite. Clinicians and the public are encouraged to report definite spider bites (with spider captured) immediately after the bite. The on-call investigator can be contacted via the Monash Medical Centre switch (telephone: 03 9550 1111) as the NASTY Study (Necrotising Arachnidism Study). Definitive identification of the spider involved by an arachnologist is essential to advance our understanding of this condition.

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  6. Macmillan DL. Envenomation by a window spider [letter]. Med J Aust 1989; 150: 16.
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  10. Atkins JA, Wingo CW, Sodeman WA, Flynn JE. Necrotic arachnidism. Am J Trop Med Hyg 1957; 7: 165-184.
  11. Auer AI, Hershey FB. Proceedings: Surgery for necrotic bites of the brown spider. Arch Surg 1974; 108: 612-618.
  12. Harvey MS, Raven RJ. Necrotising arachnidism in Australia: a simple case of misidentification [letter]. Med J Aust 1991; 154: 856.
  13. Oppenheim B, Taggart I. More in spider venom than venom? Lancet 1990; 335: 228.
  14. Atkinson RK, Farrell DJ, Leis AP. Evidence against the involvement of Mycobacterium ulcerans in most cases of necrotic arachnidism. Pathology 1995; 27: 53-57.
  15. Rees RS, Fields JP, King LE. Do brown recluse spider bites induce pyoderma gangrenosum? South Med J 1985; 78: 283-287.
  16. Callen JP. Pyoderma gangrenosum. Lancet 1998; 351: 581-585.
  17. Rees RS, Altenbern DP, Lynch JB, King LE, Jr. Brown recluse spider bites. A comparison of early surgical excision versus dapsone and delayed surgical excision. Ann Surg 1985; 202: 659-663.
  18. Strain GM, Snider TG, Tedford BL, Cohn GH. Hyperbaric oxygen effects on brown recluse spider (Loxosceles reclusa) envenomation in rabbits. Toxicon 1991; 29: 989-996.
  19. Maynor ML, Moon RE, Klitzman B, et al. Brown recluse spider envenomation: a prospective trial of hyperbaric oxygen therapy. Acad Emerg Med 1997; 4: 184-192.

(Received 19 Oct 1998, accepted 1 Jun 1999)

Authors' details Australian Venom Research Unit, Department of Pharmacology, The University of Melbourne, VIC.
Steven J Pincus, MB BS, BSc(Hons), Research Registrar.
Kenneth D Winkel, MB BS, FACTM, Director.
Gabrielle M Hawdon, MB BS, MPH, Deputy Director.
Struan K Sutherland, MD DSc, Honorary Principal Fellow.

Reprints: Dr K D Winkel, Australian Venom Research Unit, Department of Pharmacology, The University of Melbourne, Parkville, VIC 3052.
Email: k.winkelATpharmacology.unimelb.edu.au

1: Fourteen cases of acute and recurrent skin ulceration after suspected or confirmed white-tailed spider bite*

Spider identity confirmed
1. A 27-year-old woman in Queensland was bitten on the leg by a female white-tailed spider (positively identified by one of the authors, SKS). She developed a pimple-like lesion that blistered and broke down to form a 2x2cm ulcer. She was treated with doxycycline, and healed over 1 month.
2. A 38-year-old man in Victoria was bitten on the calf by a female white-tailed spider (positively identified by the Victorian Museum). The bite was painful, itchy, erythematous and blistered, and progressed to shallow ulcers, while he became feverish. He was treated with doxycycline and antihistamines, and the original lesion healed over 10 days. He has since had multiple episodes of similar lesions, with a gradual decrease in frequency.
3. A 33-year-old man in New South Wales was bitten on the leg by a white-tailed spider (also sighted by the local medical officer). Initially the bite produced a small, red, painful lesion. Culture produced a scant growth of S. aureus. The patient was treated with doxycycline, and the lesion healed, then broke down at one month into a 6x6cm ulcer that healed over four months. Spider identity not confirmed (patient reported white-tailed spider bite, but no formal identification)
4. A 39-year-old man in Queensland was bitten on the shin. The bite was painful and progressed rapidly to a 20x10cm ulcer. He presented at one week, febrile with secondary infection. Staphylococcus and Streptococcus were cultured from the wound. He was treated with intravenous and oral antibiotics, but presented again three weeks later requiring further antibiotic treatment. The ulcer healed over the next month. 5.·A 38-year-old man in Tasmania was bitten at the base of the little finger. The lesion developed initially as a reddened disc with central darkening, progressing to a painful ulcer (1x2cm). S. aureus was cultured from the lesion. He was treated with intravenous and oral antibiotics without response. Hyperbaric oxygen therapy was applied five times, until the lesion developed a granulating base.
6. A 46-year-old man in New South Wales was bitten on the back of the hand by a white-tailed spider. The bite resulted in a painful, erythematous 5x5cm area of blisters that progressed to a chronic ulcer. He was unsuccessfully treated with routine wound dressings, oral and intravenous antibiotics, developed a claw hand and underwent amputation at the wrist.
7. A 46-year-old man in New South Wales was bitten on the shin. The bite resulted in an itchy, painful swelling with a 1cm necrotic area, and the patient became febrile. He was treated with flucloxacillin and penicillin, but the ulcer slowly increased in size with central necrosis, before eventually healing over one month.
8. A 51-year-old man in Queensland was bitten on the back of the hand. Blisters at the bite site progressed to a painful ulcer that had not healed two months after the bite, when the wound was debrided and repaired with a split skin graft. Two weeks later there was blistering and loss of the graft. Regrafting was also unsuccessful, leaving a persistent 15x8cm ulcer that took six months to heal. The lesion recurred once three years later.
9. A 35-year-old man in Victoria was bitten on the palm of the hand. The bite resulted in a painful lesion with central blistering. He was treated with antibiotics. The blister broke down to a shallow ulcer that resolved slowly over a month. The patient experienced several episodes of superficial blisters over the next year.

White tailed SpiderA white-tailed spider (Lampona cylindrata, actual length 1-2 cm) -- the likely suspect in most of these cases of serious injury after spider bite. "Lampona group spiders are found throughout Australia; L. cylindrata is particularly common in disturbed and urban areas. These spiders live in crevices, under bark, rocks and leaf litter and often in houses. They attack and eat other spiders including black house spiders."

-- Australian Museum online
Accessed 11 June 1999.

10. A 33-year-old woman in Victoria was bitten on the medial malleolus. Initially a red spot, the bite site blistered on Day 1, progressing to increasing inflammation and spreading ulceration resulting in multiple ulcers on the lower leg. A biopsy showed perivascular infiltration with polymorphic neutrophils and lymphocytes. The patient was unsuccessfully treated with antibiotics and routine dressings for four months before being referred for hyperbaric oxygen therapy. Twelve sessions of hyperbaric oxygen therapy led to resolution of the ulcer, but the patient experienced several recurrences of ulcers (1-2cm self-healing) per year thereafter.
11. A 69-year-old woman in Victoria was bitten on the medial malleolus. The bite resulted in pain, erythema, oedema, multiple blisters, progressing to dry shallow ulcers, with fever. The patient was treated with intravenous antibiotics and routine wound dressings without response. Blisters and swelling increased for 10 days, then healed over three weeks. Three months after the bite the patient experienced multiple episodes of small blisters that healed in 5-7 days.
12. A 25-year-old woman in Victoria was bitten on the foot. The bite resulted in an ulcer and erythema in the first web space and swelling to the ankle. The patient was treated with oral antibiotics. The lesion healed over one month, but recurred four times in the next six months, after which the patient had 10 sessions of hyperbaric oxygen therapy. There was a minor recurrence one year after the bite.
13. A 35-year-old man in Victoria was bitten on the shin. The bite resulted in painful, erythematous, swollen, multiple superficial ulcers. A biopsy showed dermal necrosis and vasculitis infiltrated by polymorphic neutrophils. The patient was treated with intravenous flucloxacillin and penicillin, oral augmentin, immobilisation and (after two months) with a split skin graft. The graft healed over one month, but the patient presented again a year after the bite with rapid breakdown of the graft. A regraft gave a poor result and recovery was slow.7
14. A 40-year-old woman in New South Wales was bitten on the arm. The bite resulted in a red spot that grew to 2cm and developed a necrotic centre at seven days, progressing to shallow ulcers in the mid-forearm (6x3cm). Biopsy showed dermal necrosis and mixed perivascular infiltrate. Treatment with tetracycline was ineffective, but topical and oral prednisolone appeared to slow the progression of the ulcer. The patient underwent hyperbaric oxygen therapy, with resolution of the ulcer, but she has experienced subsequent recurrences.

*Identified from the Australian Venom Research Unit medical advisory service records and from the Alfred Hospital Department of Hyperbaric Medicine records.

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2: Skin necrosis following bites from two Badumna spiders

This is the first report of skin necrosis after the bite of a female black house spider. A previously well 55-year-old woman was bitten four times by two spiders that fell onto her forearm after she had sprayed them with insecticide. She felt an immediate stinging pain after the bite. The spiders were captured and later identified as female Badumna spiders (species indeterminate) (Dr Robert Raven, Museum Scientist, Arachnology, Queensland Museum, personal communication). She presented to hospital four days later with a painful, swollen forearm, was admitted and, although systemically well, was treated with intravenous flucloxacillin.
Over the next three days, several ragged ulcers with necrotic bases developed within the swollen area. Microscopy of a swab of the ulcer showed numerous leukocytes, but no organisms were seen on gram stain nor subsequently cultured. After debridement, the ulcers were allowed to heal by secondary intention. The wounds healed slowly over the next few months and have not recurred.
A black house window spiderA black house or black window spider (Badumna insignis, actual length 1-1.5 cm). "Black house spiders are widely distributed in southern and eastern Australia. They are common in urban areas. Other Badumna group spiders are found throughout Australia. Black house spider webs form untidy, lacy silk sheets with funnel-like entrances. They are found on tree trunks, logs, rock walls and buildings (in window frames, wall crevices, etc.). Badumna longinquus often builds webs on foliage."

-- Australian Museum online
Accessed 11 June 1999.

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Steven J Pincus
Kenneth D Winkel
Gabrielle M Hawdon
Struan K Sutherland