[Cutaneous loxoscelism with edematous predominance].

Abstract

Loxoscelism is the clinical condition produced by the venom of spiders belonging to the genus Loxosceles. Human cases of loxoscelism have been observed in diverse countries of different continents in temperate and tropical regions. In Chile loxoscelism is caused by Loxosceles laeta, spider with domestic habits. Loxoscelism can be observed into two well definited clinical variants: cutaneous loxoscelism (CL) and systemic or viscerocutaneous loxoscelism (VCL) which occur in around 83.3 and 16.7% cases respectively. Within the universe of CL patients a clinical modality in which necrotic lesion is not present or is insignificant, but presenting a remarkable edema, particularly when the bite is on the face, which has received the name of CL with an edematous predominance (CLEP). In this paper the individual description and the assambled analysis of 10 cases, four males and six females, age ranging from 6 to 68 years, of CLEP are presented. Nine cases occurred in warm periods spring through fall and one in winter. In six cases the accident causing spider was seen and two of these were identified as L. laeta adult females. In all cases the patients went or were transported to emergency medical services 4-24 h after the bite. The predominant initial symptom was a burning stinging sensation at the site of the bite, followed by intensive pain which expanded the neighbour areas concomitantly with the emerging and progressive edema. In four of the nine patients in who the bite was on the face, the edema involved all of it, closed both eyelids and expanded to the neck and upper part of the thorax. In three cases the enormous edema was the only significant clinical manifestation, whereas in the remaining seven conjunctly with the edema, a small violaceous plaque or a blister of serous content gave place to a little livedoid plaque (diameter 0.3-0.8 cm) which evolved to desquamation without leaving any scarring. The edema was characterized by its brilliant rose color, painful and hard which is not accompanied by regional adenopathy. Treatment of the 10 patients depended on the moment in they were seen by us. It consisted on parenteral administration, according to age and weight, of 5-10 mg of chloroprofenpyridamine maleate every 8 hours for be continued every 12-24 hours until the patient was discharged. Parenteral route was preferred in order that it was going to be adequately absorbed. With the beginning of the antihistaminic treatment a clear diminution of pain and edema was obtained, being possible its total disappearance within 4-10 days. CLEP occurs in about 4% of loxoscelism cases, has a benign prognosis and an early response to adequate medical treatment. Without discarding the sensibility factor of the affected individual, there exist the impression that the edema may abort the necrotic process when it dilutes the enzymatic process produced by L.laeta venom. In Chile, the differential diagnosis must be planted with the following clinical entities: bites of hematophagous insects on the face, bee stings, Chagas' disease with facial port of entry and angioneurotic edema.