There are approximately 40 – 46,000 described species of spiders in the world. They are capable of crawling in luggage, boxes, duffel bags, fruit crates, etc. and can be dispersed around the world. This does not mean they are necessarily indigenous to an area when found. For example, in Michigan a few years ago, a contractor was bit by a confirmed Brown Recluse. In exploring the history and tracking the materials used for shipping, it was noted lumber was shipped to the building site from Texas. Brown recluse spiders and NOT indigenous in Michigan.
For Survive Outdoors, we are going to stay within North America and focus on the most common spider interactions. It should be noted – There is a large psychological component to spiders and the fear that they generate. Spiders are incredibly beneficial and with more education we can only hope others will not be so quick to resort to the shoe or flyswatter when spotting these amazing creatures.
The vast majority of spiders are carnivorous. They usually have to ensnare their prey and then immobilize before consuming. Venoms of spiders are primarily neurotic and proteolytic peptides with biologic amines. Proteolytic enzymes are also found in some snake venoms. Their primary role is to breakdown protein.
Out of approximately 45,000 spiders, only about a couple dozen are dangerous to humans. Of those couple dozen, only two in the United States are concerning.
The most common diagnosis for me, personally, and the patients I have treated over the last forty years are Staph infections or skin abscesses. This also includes MRSA Methicillin Resistant Staph Aureus. These are all too frequently confused with the Brown Recluse bite and at times there is no explanation I can give to convince a patient it is not a spider bite. I mean, saying one has a spider bite is much more exotic and interesting than saying one has a staph infection. Humans cling to this diagnosis and wear it like a badge of courage.
Among the most common differential are: skin abscess, insect bite, herpes, shingles or heroes zoster, allergic dermatitis and plant dermatitis – specifically Hogweed or Cow Parsnip.
The patient’s medical history is crucial and can help when formulating a diagnosis.
Specific treatment of spider bites will be addressed for each individual spider we discuss. Please go to specific species: Brown Recluse, Black Widow or Tarantula.