The brown recluse spider, known for its potentially medically significant bite, often raises questions about its geographic distribution. This article clarifies the brown recluse’s established presence and addresses common misconceptions about its habitat.
Brown Recluse Presence in Washington
The brown recluse spider (Loxosceles reclusa) is not native or established in Washington State. Its natural habitat is primarily concentrated in the central and south-central United States, extending from Nebraska south to Texas and east to Ohio, Kentucky, and Georgia. While rare, isolated instances have occurred in Washington, these are typically due to accidental transport, often via moving boxes or personal belongings from its native range. Such occurrences do not indicate an established population. Therefore, encountering a brown recluse spider in Washington is highly unlikely, and reported bites are almost always misdiagnosed.
Identifying the Brown Recluse
Accurate identification of the brown recluse spider requires attention to distinct physical characteristics. One recognized feature is the “violin” or “fiddle” shape on its cephalothorax, the fused head and thorax region. This dark marking has the neck of the violin pointing towards the abdomen. The spider is uniformly brown, without stripes, bands, or other patterns on its abdomen or legs.
A distinguishing feature of the brown recluse is its unique eye arrangement. Unlike most spiders with eight eyes, the brown recluse has six eyes arranged in three pairs, forming a semicircle. These spiders are relatively small, with a body length typically ranging from 6 to 20 millimeters. Identifying a brown recluse based solely on a “violin” mark can be misleading, as other spiders may have similar markings; observing the eye pattern is essential for positive identification.
Commonly Confused Spiders in Washington
Several spider species in Washington State are frequently mistaken for the brown recluse due to their brown coloration or general appearance. The hobo spider (Eratigena agrestis) is identified by its funnel web and a chevron pattern on its abdomen, differing from the brown recluse’s uniform abdomen and violin mark. The giant house spider (Eratigena atrica) is much larger than the brown recluse and lacks the violin marking.
The yellow sac spider (Cheiracanthium inclusum or mildei) is also sometimes confused, but it is typically pale yellow or green and lacks the violin shape and distinctive eye pattern. Unlike the brown recluse, hobo spiders, giant house spiders, and yellow sac spiders all have eight eyes arranged in different patterns. These Washington spiders are not considered medically significant like the brown recluse.
Responding to a Spider Bite
If a spider bite is suspected, general first aid measures can help manage symptoms. Cleaning the bite area thoroughly with soap and water helps prevent infection. Applying a cold compress or ice pack to the affected area can reduce swelling and discomfort. Elevating the bitten limb can also minimize swelling.
Most spider bites are harmless, causing minor, localized reactions such as redness, itching, or mild pain. However, seek medical attention if symptoms worsen, if there are signs of infection (increasing pain, pus, or fever), or if the bite causes a severe allergic reaction. Medical consultation is also recommended if the bite appears to be spreading or if the affected individual has underlying health conditions.