A 3-year-old female was brought to the emergency centre by her father with fever and a ‘rash’ on her buttocks. The rash began a few days earlier as a bruise-like spot and was spreading. She had not had diarrhoea or any other symptoms. She had been in good health and was taking no medications. When asked ‘what happened’ the child replied ‘a skeeter bit me’. Grandmother, who cared for the child, stated that there had been ongoing restoration work performed in the crawl space beneath the child’s bedroom and they had seen many spiders in the house. On physical examination the child had a temperature of 39.8°C rectally. There was a 10 × 10 cm oval area on the left buttock which was warm to touch and erythematous with a darker centre. There was a 4 × 5 cm round, erythematous lesion on the right buttock. Both areas felt thickened and indurated with a rough surface (peau d’orange). There were no vesicles, blisters or bullae, as shown in Image 81. https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9780429170423/236ca68c-f283-4df8-88b2-3b8ff49bccc9/content/fig81.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>

What common form of inflicted injury was this mistaken for?

How can these conditions be differentiated?

The initial impression was that this child has been intentionally burned. Clinical laboratory testing for spider venom was not available but a presumptive diagnosis of spider bite was made. A complete blood count, blood and wound cultures and all other laboratory tests were normal.

The lesion was undergoing the typical colour transition seen in venomous bites – ‘red, white, blue’ – as the cutaneous reaction to toxin progressed through vasodilatation, vasoconstriction and thrombosis. Fever, as noted in this child, results from systemic reaction to toxin. Other serious systemic reactions may occur such as haemolysis, rhabdomyolysis, methemoglobinemia, haemoglobinuria, platelet aggregation and renal failure. The child was monitored for several days. 1 Extensive skin necrosis resulted and the child underwent skin grafting of the affected sites. 2