The spider biting apparatus is short and bites are only possible in experimental animals with pressure on the spider's back. Thus many bites occur when a spider is trapped in a shirt or pant sleeve. There is no commercial chemical test to determine if the venom is from a brown recluse. The bite itself is not usually painful. Many necrotic lesions are erroneously attributed to the bite of the brown recluse. (See Note). Skin wounds are common and infections will lead to necrotic wounds, thus many severe skin infections are attributed falsely to the brown recluse. Many suspected bites occurred in areas outside of its natural habitat. A wound found one week later may be misattributed to the spider. The diagnosis is further complicated by the fact that no attempt is made to positively identify the suspected spider. Because of this, other, non-necrotic species are frequently mistakenly identified as a brown recluse. Several certified arachnologists are able to positively identify a brown recluse specimen on request. Reports of presumptive brown recluse spider bites reinforce improbable diagnoses in regions of North America where the spider is not endemic such as Florida, Pennsylvania, and California. The mnemonic "NOT RECLUSE" has been suggested as a tool to help professionals more objectively exclude skin lesions that were suspected to be loxosceles. Numerous (should be solitary), Occurrence (wrong geography) Timing (wrong season), Red Center (center should be black), Elevated (should be shallow depression), Chronic, Large (more than 10 cm), Ulcerates too quickly (less than a week), Swollen, Exudative (there should be no pus, it should be dry)
Loxoscelism
Adiposogenital dystrophy
Phocomelia
Dolichostenomelia
Micrognathism
Rhizomelia
Sirenomelia
Microorchidism