Spider Bite? Get it Right!
Brown recluse spider bites (loxoscelism) cause skin changes that are similar to about 40 medical conditions, resulting in false diagnoses. To prevent such mistakes, Missouri dermatologists have developed a mnemonic device based on their combined 50 years of experience observing bites. The letters NOT RECLUSE summarizes what to look for when evaluating a suspected bite. The mnemonic is aptly named for summarizing factors that are not typical of a brown recluse bite.
• N stands for numerous. Since bites usually occur when a person attempts to crush a spider, a brown recluse usually bites once or maybe twice. If a patient has many necrotic lesions think herpes zoster or bedbugs, not recluse.
• O stands for occurrence; brown recluse bites often happen when a person disturbs a hidden spider. A lesion that happens during gardening, for example, is probably not from a spider.
• T represents timing. If a bite happens outside of April through October, it’s unlikely a brown recluse.
• R is for a red center that can be observed. A brown recluse bite actually results in a lesion with a pale, blue-white or purple center due to immediate destruction of the capillary bed.
• E stands for elevated; recluse bites are flat or sunken.
• C equals chronic. Most recluse bites heal within 3 months, so a lesion that is older is more likely pyoderma gangrenosum or maybe nonmelanoma skin cancer.
• L refers to the expected size. Most recluse bites are not large, a wound that is bigger than 10cm is more suggestive of pyoderma gangrenosum.
• U suggests looking for when the ulceration occurred; recluse bites ulcerate one to two weeks after the bite occurs.
• S is for swollen. Do not expect a lot of swelling for a recluse bite except if a bite is on the face or feet.
• E equals exudate. A recluse bite will not be exudative, moist or purulent, so pus is a negative sign for a brown recluse bite diagnosis
The authors state that having two or more of these signs strongly suggest that the suspected bite is not from a brown recluse and that an infection is far more likely.
Byline: Martha L. Sikes, MS, RPh, PA-C
Posted: July 6, 2017
Adapted from the original article.