Spider bite-induced erythema multiforme

Abstract

Erythema multiforme (EM) is an immune-mediated mucocutaneous eruption characterized by symmetrically distributed, polymorphic targetoid lesions, mostly on the distal parts of the extremities. It occurs mostly in the setting of an infection in certain predisposed individuals. A 30-year-old pregnant woman was presented with a necrotic erythematous lesion on her right thigh following a spider bite. As she was pregnant for 16 weeks, no systemic medication was given. On the 8th day of the spider bite an erythematous vesicular and targetoid rash was seen on the distal parts of her extremities. Based on the clinical and histopathological findings, lesions were diagnosed as EM. She had not used any medication for 4 months and she gave no prior history of herpetic infection. So her EM lesions were thought to be an ID reaction most probably due to the spider bite. As far as we know, this is the first reported case of EM induced by a spider bite.

Erythema multiforme triggered by a spider bite in an adult female patient

“…EM usually appears in the setting of infection such as herpes simplex virus (HSV1 or HSV2) or Mycoplasma pneumoniae, but it may also be idiopathic [12]. Lesions mostly occur in a symmetric, acral distribution and may remain fixed at the same site for 7 days or more [2]. In our case, the clinical history combined with the typical skin lesions confirmed the diagnosis of EM.…”

“…Moderate lesions -as in this case-are the most common [7]. Apart from local lesions, the skin reaction to a spider bite may present as a maculopapular eruption over the entire body which has been reported in 5-32% of the published cases [2]. Acute generalized exanthematous pustulosis (AGEP) and pustular skin reactions have also been described [4,8].…”

“…Hence, we could implicate the spider bite in its occurrence. There is one case of EM triggered by a spider bite reported in the literature [2]. The diagnosis was also established based on the clinical history and laboratory findings.…”

“…Drug intake is implicated in fewer than 10% of cases [1]. EM may also be caused by fungal infections, neoplasms, connective tissue disorders, or it may be idiopathic [2]. Here we report a patient presenting with EM lesions following a spider bite.…”

“…Erythema multiforme (EM) is an immune-mediated condition characterized by erythematous plaques or papules that evolve into targetoid lesions distributed mostly on the distal parts of the extremities [1,2]. EM is due to an infection in more than 90% of cases particularly herpes and Mycoplasma infections.…”