Acute allergic reaction following contact with a spider.

Allergic reactions following contact or injury from arachnids are uncommon. There have previously only been reports of urticarial reactions following contact with large spiders from the family Theraphosidae. A 55-year-old male presented to hospital with a generalised urticarial rash following contact with a spider, identified by the person as a huntsman spider (Family: Sparassidae). The spider had crawled over both his arms for a period of minutes. About 30 min later, he developed a rash on the arms which spread to the trunk. He then developed bradycardia and hypotension that required treatment with atropine, adrenaline and histamine antagonists. He recovered within 6 h and had no further problems. The early allergic reaction in this case was most likely the result of contact with the spider.