ARTICLE
Auteur(s) : Ebtisam
Elghblawi
BUM Hospital, Tripoli-Libya
A 36-year-old Libyan lady, who was 20 weeks pregnant, presented
to the Dermatology clinic with a necrotic brown lesion. The lesion
was noticed on waking in the morning two days prior to
presentation. It was painful and associated with swelling and
severe itching. The lesion was located on the dorsal aspect of the
right foot (figure
1) about 5 × 7 cm, with a central bluish-purple
discolouration, and three-yellow oozing necrotic ulcerations at the
base. The lesion was surrounded by a ragged erythematous
border.
There was no evidence of systemic upset and baseline
investigations were normal. Community-acquired
Methicillin-Resistant Staphylococcus Aureus (MRSA) was excluded by
negative pus culture. Based on the history and the typical
appearance of the lesion, the diagnosis was thought to be brown
recluse spider bite. She was treated with oral antibiotics as the
wound appeared infected. She also received simple analgesics,
non-sedative antihistamine, and prednisone 30 mg for 5 days to
resolve the swelling and surrounding inflammation [7]. She was
advised to rest and to keep her foot elevated to reduce the local
oedema. The lesion improved significantly and pain and swelling
subsided by day ten, when she attended the follow up clinic.
Discussion
The brown recluse (Loxosceles) is one of 100,000 species of spider
present worldwide. Its bite can cause skin necrosis. Typically, the
area affected becomes intensely painful, with localised erythema
and oedema within 2-3 hours of the bite. A central bulla
develops in 12-24 hours, followed by an area of central necrosis.
Presentations can vary [1] and systemic symptoms are unusual [2,
3]. Our patient was unaware of being bitten; however the diagnosis
was made on the basis of the history and the typical appearance of
the lesion [4, 5]. She did not exhibit bulla formation; which may
have been masked by the scratching due to severe itching. The
ulcerative lesion over her right foot developed within the first
two days, and could be the site of the spider bite (figure, double
fang mark).
There was no impact on her pregnancy and she was closely
monitored by her obstetrician. The diagnosis of spider bite is a
speculative diagnosis [4, 5], but other causes should be considered
and excluded, mostly MRSA. Spider bites usually occur when the
victim accidentally comes into physical contact with the spider
while sleeping, or getting dressed [6]. The nature and severity of
the lesion varies from case to case. Predictors of a rapid healing
involve mild oedema and erythema and minimum necrosis at
presentation. Younger ages without chronic illnesses, such as
diabetes, and early medical intervention have a better prognosis
[6].
Necrotic arachnidism is a common health problem in Libya. This
could be accredited to the year round warm climate. It is
especially common in summer and in rural areas. However, there are
no reports in the literature about the spider species population in
Libya, as classification and recognition requires an
arachnologist.
A review of the medical literature reveals that most current
concepts regarding brown recluse spider envenomation are based on
assumption and supposition. There is no laboratory test available
to confirm the diagnosis, which remains based on history and
typical presentation [7]. Attempts are ongoing to construct a
strategy for a definitive diagnosis of the brown recluse spider
bite, but none is yet available.
Acknowledgements
Author disclosure: Nothing to disclose.
Références
1 Nunnelee JD. Brown recluse spider bites: a case report. J
Perianesth Nurs 2006; 21: 12-5.
2 Rhoads J. Epidemiology of the brown recluse spider bite.
J Am Acad Nurse Pract 2006; 19: 79-85.
3 Diaz JH, Leblanc KE. Common Spider Bites. Am Fam
Phys 2007; 75: 869-73.
4 Furbee RB, Kao LW, Ibrahim D. Brown recluse
spider envenomation. Clin Lab Med 2006; 26: 211-26; (IX-X).
5 Leach J, Bassichis B, Itani K. Brown recluse
spider bites to the head: three cases and a review. Ear Nose Throat
J 2004; 83: 465-70.
6 James W, Mold JW, David M. Management of Brown
Recluse Spider Bites in Primary Care. The J Am Board Family Pract
2004; 17: 347-52.
7 Anderson PC. Loxoscelism threatening pregnancy: five
cases. Am J Obstet Gynecol 1991; 165 (5 Pt 1): 1454-6.
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