Correspondence

Bites of the Brown Recluse Spider

N Engl J Med 2005; 352:2029-2030May 12, 2005

Article

To the Editor:

Swanson and Vetter discuss the bites of brown recluse spiders in their review article (Feb. 17 issue).1 We are infectious-disease specialists who practice or have practiced in Norwalk, Connecticut, where, according to the article, such venomous spiders are not present.

However, during the past 30 years, we have each seen six to eight cases that were typical of necrotic arachnidism. The spiders had generally not been seen, but in almost every instance the patient had disturbed a rarely entered area and had noted an abrupt stinging or itching sensation. This sensation was usually followed within hours by the appearance of an increasingly painful papule with surrounding erythema. During the ensuing 24 to 48 hours, the papule became black and necrotic and the painful erythema spread, often in association with the development of fever and myalgias. These cases were usually referred to us because of the absence of a response to antibiotics. Our management consisted of oral administration of corticosteroids, usually without antibiotics. This therapy appeared to be dramatically effective.

Although our experience is admittedly anecdotal, we suggest that it represents experience with true necrotic arachnidism and, furthermore, that early corticosteroid therapy is very effective.

Ernest Atlas, M.D.
2115B Vermont Rd., Vail, CO 81657
ernieatl@comcast.net

Arthur Yee, M.D.
Norwalk Hospital, Norwalk, CT 06856

1 References

1
Swanson DL, Vetter RS. Bites of brown recluse spiders and suspected necrotic arachnidism. N Engl J Med 2005;352:700-707
Full Text | Web of Science | Medline

To the Editor:

Swanson and Vetter do not adequately address the serious complications associated with envenomation by brown recluse spiders, such as life-threatening hemolysis, coagulopathy, and sepsis.1 These life-threatening reactions are of particular concern, given that the potency of venom from Loxosceles reclusa found in south central areas of the Midwest is greater than that of the venom of loxosceles species found in Arizona.

During my 31 years as a medical toxicologist, I have managed more than 50 cases of hemolysis (most associated with coagulopathy), including 2 involving the death of a child from presumptive loxoscelism and at least 4 other cases involving the death of a child (in Kansas, Oklahoma, Tennessee, and Kentucky).2 I readily agree with the authors that the best treatments for the multiple complications of envenomation by brown recluse spiders (among them cutaneous and systemic or visceral complications) are largely controversial, since evidence-based guidelines on the treatment of envenomation in humans cannot be determined.

Gary S. Wasserman, D.O.
Children's Mercy Hospitals and Clinics, Kansas City, MO 64108

2 References

1
Wasserman G, Lowry J. Loxosceles spiders. In: Brent J, Wallace K, Burkhart K, Phillips S, Donovan J, eds. Critical care toxicology. New York: Elsevier, 2005:1195-203.

2
Wasserman G, Garola R, Marshall J, et al. Death of a 7-year-old boy by presumptive brown recluse spider bite. J Toxicol Clin Toxicol 1999;37:614-615

Author/Editor Response

With respect, we do not believe that Drs. Atlas and Yee saw necrotic arachnidism in Norwalk. Connecticut's spider fauna has been exhaustively documented by the renowned American arachnologist B.J. Kaston1; of the 50 states, none has a more comprehensive local arachnologic database. No populations of brown recluse spiders have ever been verified in Connecticut, and it is highly unlikely that the attribution of any case of necrotic arachnidism to recluse spiders is accurate. The term “necrotic arachnidism” is best reserved for verified spider bites manifested as necrotic lesions; otherwise, another, more accurate term — for example, “idiopathic necrotic lesion” or “focal necrosis of the skin”2 — should be used.

There are several skin diseases that have a sudden onset, feature ulceration, and respond to systemic glucocorticosteroids; pyoderma gangrenosum is one example. The appearance of an ulcer and the subsequent coincidental healing with the use of any of the therapies reported to help spider bites do not validate the diagnosis of a spider bite. Furthermore, the unverified diagnosis of a spider bite in areas where loxosceles spiders are endemic is insufficient proof of the local existence of brown recluse spiders or other allegedly necrosis-inducing spiders, given the arachnologic evidence that resoundingly refutes that misconception. In such areas, unless a spider is caught in the act of biting and is subsequently identified as capable of producing an ulcer, ulcers should be attributed to other causes, many of which we listed in our article.

On the other hand, as compared with Connecticut, Missouri is a loxosceles hotbed. We appreciate and acknowledge Dr. Wasserman's comments about the occasional severe reaction in persons who receive a loxosceles bite. Fortunately, such reactions are rare, but unfortunately, there is no proven effective treatment for them. Our point is that even in areas where the spider is endemic, physicians need to keep an open mind and consider more likely diagnoses when faced with possible but undocumented necrotic arachnidism. Doing so helps to prevent diagnostic mistakes, such as a missed diagnosis of necrotizing fasciitis.3

David L. Swanson, M.D.
Mayo Clinic, Scottsdale, AZ 85259

Richard S. Vetter, M.S.
University of California, Riverside, CA 92521

3 References

1
Kaston BJ. Spiders of Connecticut: state geological and natural history survey of Connecticut. Bulletin 70. Hartford, Conn.: Department of Environmental Protection, 1981:1-1020.