Cutaneous Loxoscelism Caused by Loxosceles Anomala

IMAGESLCLT Cutaneous loxoscelism caused by Loxosceles anomala

FÁBIOCutaneous loxoscelism caused by Loxosceles BUCARETCHI anomala 1, EDUARDO MELLO DE CAPITANI1, STEPHEN HYSLOP1, RAFAEL SUTTI1, THOMAZ A.A. ROCHA-E-SILVA2, and ROGERIO BERTANI3 1Faculty of Medical Sciences, State University of Campinas, Campinas Poison Control Center, Campinas, Brazil 2Department of Physiological Sciences, Faculty of Medical Sciences, Santa Casa de Sao Paulo, Sao Paulo, Brazil 3Butantan Institute, Sao Paulo, Brazil

A previously healthy 35-year-old female was bitten on the anterior right thigh by a brown spider while dressing her trousers; the spider was stored and later identified as an adult female Loxosceles anomala. Clinical evolution involved a relatively painless bite with mild itching, followed by local, indurated swelling and a transient, generalized erythrodermic rash at 24 h post-bite. The local discomfort was progressive, and involved changes in the lesion pattern, with pain of increasing intensity. The patient was admitted 60 h post-bite, showing an irregular blue plaque surrounded by an erythematous halo lesion, located over an area of indurated swelling. Considering the presumptive diagnosis of cutaneous loxoscelism, she was treated with five vials of anti-arachnidic antivenom i.v. without adverse effects. There was progressive improvement, with no dermonecrosis or hemolysis; complete lesion healing was observed by Day 55. The clinical features and outcome were compatible with cutaneous loxoscelism and similar to those reported for other Loxosceles species.

Keywords Brown spider; Cutaneous loxoscelism; Loxosceles anomala

F(ab´)2 antibodies against Loxosceles gaucho, Phoneutria A previously healthy 35-year-old female was bitten on the nigriventer, and Tityus serrulatus venoms] without adverse

For personal use only. anterior right thigh by a brown spider while dressing her trou- effects. Approximately 18 h after AV infusion there was a sers (1 p.m., time zero); the spider was killed and stored at the reduction in the pain and a qualitative clinical assessment that time of the bite for identification. Clinical evolution involved the lesion progression had been stopped; at this point, the a relatively painless bite with mild itching. At 24 h post-bite patient was discharged. Sequential hemograms revealed no the patient noted progressive local swelling with induration, indication of hemolysis. associated with a transient, generalized erythrodermic rash The patient did not develop dermonecrosis and complete that was most intense on the face and trunk. By 48 h post-bite, lesion healing was observed by Day 55 post-bite. Fig. 1(A) there was progressive local discomfort with pain of increasing and (B) shows the lesion aspect 6 and 55 days post-bite, intensity (stinging burning sensation) and changes in the respectively. On the fifth day post-bite, the patient brought

Clinical Toxicology Downloaded from informahealthcare.com by UNICAMP on 09/20/10 lesion pattern. Photos of the lesion e-mailed by the patient to the dead spider that had caused the bite, subsequently identi- the Campinas Poison Control Center 57 h post-bite revealed fied by an expert arachnologist (co-author RB) as a female an irregular blue plaque surrounded by an erythematous halo. adult of Loxosceles anomala.1 There was no complaint of fever, pallor, jaundice, or change The genus Loxosceles (Heineken and Lowe, 1832) has a in urine color; a presumptive diagnosis of cutaneous worldwide distribution in temperate and tropical regions and loxoscelism was then made. The patient was admitted to the comprises at least 100 species.2–4 Envenoming by these spiders university hospital 3 h later and had an irregular lesion (6 cm generally results in local dermonecrosis with gravitational × 4 cm) with the characteristics described above, located over spreading, whereas severe systemic complications, such as an area (20 cm × 12 cm) of indurated swelling. intravascular hemolysis and acute renal failure, are unusual.3,4 In view of the progressive signs of local envenoming, the The diagnosis of loxoscelism is difficult and rarely based on patient was treated with five vials of anti-arachnidic antivenom the identification of the spider, but on epidemiological data, i.v. [AV, Instituto Butantan, Brazil; 5 mL/vial containing historical findings, and clinical signs and symptoms.3,4 In general, less than 15% of bitten patients bring the spider for identification3; in addition, as the clinical signs and symp- Received 6 May 2010; accepted 15 June 2010. toms are not particularly pronounced during the first few Address correspondence to Fábio Bucaretchi, Centro de Controle de hours after a bite, the patients usually present for evaluation Intoxicacoes HC/UNICAMP, Campinas, CEP 13081-970, Brazil. 3,4 E-mail: [email protected] only 24–48 h after being bitten. Clinical Toxicology vol. 48 no. 7 2010 Cutaneous loxoscelism caused by Loxosceles anomala 765

(A) (B)

Fig. 1. Aspect of the local lesion 6 (A) and 55 (B) days post-bite, respectively. (A) Irregular blue plaque surrounded by an erythematous halo, resembling local vasculitis. (B) Complete lesion healing 55 days post-bite.

Most bites of Loxosceles in Brazil are caused by L. inter- Declaration of interest media, L. laeta, and L. gaucho.3,4 Loxosceles anomala is an uncommon species,1 and no confirmed cases of bites by this The authors report no conflicts of interest. The authors alone species have previously been reported. However, the circum- are responsible for the content and writing of this paper. stance, clinical features, and outcome described here were compatible with cutaneous loxoscelism, and were similar to those reported for other Loxosceles species.3,4 AV has been used to treat clinical loxoscelism in Brazil References since the 1960s and shows good cross-reactivity in neutral- izing the dermonecrotic and lethal activities of several 1. Álvares ESS, Rodrigues T, De Maria M. On Loxosceles anomala (Mello 5 Leitão) (Araneae: Sicariidae). Rev Ibérica Aracnol 2004; 10:293–295. Loxosceles venoms in rabbits. Those who advocate the use 2. Platnick NI. The World Spider Catalog, Version 10.5. American of AV based on anecdotal and extensive clinical experience Museum of Natural History. http://research.amnh.org/iz/spiders/catalog/

For personal use only. stress that AV therapy can be beneficial in decreasing the SICARIIDAE.html. Accessed 30 March 2010. lesion size and cure time, and in attenuating the systemic 3. Hogan CJ, Barbaro KC, Winkel K. Loxoscelism: old obstacles, new effects.5 directions. Ann Emerg Med 2004; 44:608–624. 4. Da Silva PH, da Silveira RB, Appel MH, Mangili OC, Gremski W, In conclusion, the clinical findings described here indicate Veiga SS. Brown spiders and loxoscelism. Toxicon 2004; 44:693–709. that L. anomala venom probably shares similar activities with 5. Pauli I, Puka J, Gubert IC, Minozzo JC. The efficacy of antivenom in those of other Loxosceles species. loxoscelism treatment. Toxicon 2006; 48:123–137. Clinical Toxicology Downloaded from informahealthcare.com by UNICAMP on 09/20/10