My 20 year old son woke up the other day with what looked like a spider or bug bite on the back of his leg near his butt. It was bright red about 1/2" in diameter. My wife told him to put some anti bacterial cream on it and watch it for a day or so. Yesterday it was well over an inch in diameter, bright red, tender, with a black dot and white puss in the center. She took him to an urgent care center, which immediately said it wass mercers infection and it was a type of staph infection and gave him 2 antibiotic prescriptions. Today it is so tender, he can't touch it and has a hard time sitting down and it is much larger and turning reddish purple. They never took into consideration it could be a bug or spider bite. I have seen several bites from brown recluse spiders and this looks very similar.
What is mercers- I have never heard of it- and what should I do?
Are you in an area where the recluse typically is found?
I just did some reading up on the bites of these spiders, and it seems the only sure way to determin if that is the cause is to actually have the spider. That being said, the article also said it was common for physicians to treat for staphylococcus and "flesh-eating" streptococcus and a myriad of other possibilities before thinking brown recluse bite.
Here's the symptons from the article i'm referring to:
the physical reaction to a brown recluse spider bite depends on the amount of venom injected and an individual's sensitivity to it. Some people are unaffected by a bite, whereas others experience immediate or delayed effects as the venom kills the tissues (necrosis) at the site of the bite. Many brown recluse bites cause just a little red mark that heals without event. The vast majority of brown recluse bites heal without severe scarring (http://spiders.Ucr.Edu/avoidbites.Html).
Initially, the bite may feel like a pinprick or go unnoticed. Some may not be aware of the bite for 2 to 8 hours. Others feel a stinging sensation followed by intense pain. Infrequently, some victims experience general systemic reactions that may include restlessness, generalized itching, fever, chills, nausea, vomiting, or shock. A small white blister usually initially rises at the bite site surrounded by a swollen area. The affected area enlarges and becomes red, and the tissue is hard to the touch for some time. The lesion from a brown recluse spider bite is a dry, blue-gray or blue-white, irregular sinking patch with ragged edges and surrounding redness--termed the "red, white, and blue sign." the lesion usually is 1Â½ inches by 2Â¾ inches or smaller. Characteristics of a bite are further discussed at http://www.Amednews.Com/free/hlsa0805.
The bite of the brown recluse spider can result in a painful, deep wound that takes a long time to heal. Fatalities are extremely rare, but bites are most dangerous to young children, the elderly, and those in poor physical condition. When there is a severe reaction to the bite, the site can erupt into a "volcano lesion" (a hole in the flesh due to damaged, gangrenous tissue). The open wound may range from the size of an adult's thumbnail to the span of a hand. The dead tissue gradually sloughs away, exposing underlying tissues. The sunken, ulcerating sore may heal slowly up to 6 to 8 weeks. Full recovery may take several months and scarring may remain.
It is difficult for a physician to accurately diagnose a "brown recluse bite" based simply on wound characteristics. It is absolutely necessary to have the spider for a positive identification. Necrotic wounds can result from a variety of agents such as bacteria (staphylococcus, "flesh-eating" streptococcus, etc.), viruses, fungi, and arthropods (non-recluse spiders, centipedes, mites, ticks, wasps, bedbugs, kissing bugs, biting flies, etc.). Necrotic conditions also can be caused by vascular and lymphatic disorders, drug reactions, underlying diseases states, and a variety of other agents. An annotated list of conditions that could be mistaken for a brown recluse spider bite is available at http://www.Ama-assn.Org/amednews/2002/08/0
5/hlsa0805.Htm. Misdiagnosis of lesions as brown recluse bites can delay appropriate care.