A 69-year-old Spanish woman was admitted to our hospital due to sudden onset facial oedema after an arthropod bite. During the night, while she was asleep, an arthropod walking across her face was noted and she tried to remove it. She noted an acute pain over the upper lip. No flying or terrestrial arthropod was seen when the light was switched on. Nevertheless next day a partially “knocked out” spider was captured between the sheets of her bed. The patient lives in a single-family house in Talamanca del Jarama, a village located in a rural area of the Province of Madrid (3500 inhabitants).
On admission at the emergency room the burning pain was still present, and an asymmetrical left sided facial oedema was noted. The bite occurred at the left side of the upper lip approximately 2cm from philtrum and a double mark corresponding to the bite of the arthropod (the chelicerae or jaws of a spider bite marks) could be lightly noticed. Surrounding this bite mark a pale plaque of approximately 1.5cm of maximum diameter could be seen, surrounded by an erythematous halo of approximately 2.5cm. General symptoms such as general discomfort, fever, dyspnoea or rash were absent. No lymphadenopathies were noticed. Methylprednisolone and amoxiciline–clavulanate were started at the emergency room. Blood parameters were normal. A facial CT-scan was performed, showing mild subcutaneous oedema, with no other bone or soft-tissue lesions.
Antibiotics and steroids were stopped at hospitalisation (48h after those treatments were started). The patient had a very good self-limiting evolution and was discharged. At ambulatory follow-up, six days after the bite, necrosis signs started at the chelicerae bite marks and expanding approximately 1cm of diameter (where it was the white plaque). The pain was well relief with habitual analgesics. Drainage and chirurgic debridement were not required.
An entomological study categorised the spider as Loxosceles rufescens. Together with the typical clinical manifestations, this gave us a definitive diagnosis of Cutaneous Loxoscelism with an Oedematous Predominance (CLEP) (Fig. 1).
Spider of the genus Loxosceles are also called “brown spiders”. Their main characteristic is a brown violin-shape pattern located on the prosoma (cephalothorax).1 They habit in isolated places indoors, rather than outdoors. Bites occur when they feel endangered and have been reported mainly in spring and summer.2
L. rufescens is known to live in the Mediterranean Basin.1 However, not many cases of Loxosceles spider bite have been reported in the Iberian Peninsula. According to modified loxoscelism criteria settled by Rader et al.,3 the case presented should be considered as “documented”. Only few other documented cases have been reported in Spain,4,5 although there are some more presumptive and probable cases6–8 reported.
Two main subtypes of loxoscelism have been described: Cutaneous and systemic or visceral loxoscelism.1
Most common symptoms of cutaneous loxoscelism are oedema and erythema, burning pain and perilesional hyperesthesia. Few hours after the bite a pale-livedoid plaque appears surrounded by an erythematosus area. This pale patch is caused by vasoconstriction and can develop in necrosis in a period of 4–5 days.2 This is explained by the cytotoxic effect of the venom, which activates complement and induces neutrophil chemotaxis and apoptosis of keratinocytes, producing this dermonecrosis.1
Visceral loxoscelism occurs when venom is injected directly in the blood stream, triggering hemolysis, vasculitis and coagulation alterations. Patients develop fever, haematuria and jaundice in the first 6h, progressing to decreased level of consciousness and coma with a 25% of mortality.1
Oedema is not a common finding of loxoscelism, most of the bites occur at the limbs.2 A rare type of cutaneous loxoscelism is CLEP, described mainly when the spider bite takes place in the face, usually with a benign prognosis. CLEP is presented frequently with an important oedema, that causes difficulties in diagnosis, and necrotic eschar, is often absent or very small. It is postulated that oedema may abort the necrotic process as it dilutes the venom injected. CLEP occurs in about 4% of loxoscelism cases.9 To our knowledge, we present the first reported case of CLEP in Spain.
There is no consensus about the best treatment. As it is, in most cases, a self-limiting process, main treatment is supportive.2
Conflict of interestThe authors declare not to have any conflict of interest.
