The cellar spider (family Pholcidae) is a common household arachnid frequently encountered in quiet, dark spaces. Often mistakenly called a “daddy long legs,” this confusion, coupled with persistent urban myths, has led to unnecessary anxiety about its bite. This article clarifies the cellar spider’s identity and details the actual effects that occur if a bite were to penetrate human skin.
Identifying the Cellar Spider
Cellar spiders are easily recognizable by their pale yellow, light brown, or gray coloration and extremely long, delicate legs relative to a small, oval body, typically about one-quarter inch long. They are frequently found in basements, cellars, crawlspaces, and garages, which offer the cool, damp, and undisturbed environments they prefer. These spiders construct loose, messy, three-dimensional webs often seen in the corners of rooms or hanging from ceilings, where they frequently suspend themselves upside down.
The Reality of the Bite
Cellar spiders are non-aggressive and highly reluctant to bite humans, preferring to use their defensive “vibrating” behavior when disturbed. The common myth asserts that this spider has the world’s most potent venom but cannot bite due to fangs that are too short. While their fangs are short and fragile, they can potentially pierce thin layers of human skin under duress, but this is exceedingly rare. The belief that their venom is highly potent is a misconception, perhaps arising from their ability to prey on dangerous spiders like black widows. The venom is specifically adapted for immobilizing small insect prey, not mammals. Studies show that while it contains various proteins, its effect on humans is inconsequential. The spider’s physical limitations and its mild venom both contribute to its lack of medical significance.
Immediate Effects and Symptoms
If a cellar spider manages to bite and inject venom, the symptoms are typically negligible or extremely mild, akin to a pinprick or a mosquito bite. The initial sensation is usually a brief, localized sting that quickly subsides. Any reaction is limited to the immediate bite site. The area may show slight, temporary redness or minor irritation, possibly accompanied by minimal localized swelling. These mild symptoms usually resolve on their own, often within a few minutes or hours, without any lasting effect. Systemic reactions, such as nausea, fever, or muscle pain, are virtually unheard of with this species.
Action Steps Following a Bite
Given the mild nature of a cellar spider bite, management focuses on basic wound care to prevent secondary infection. First, clean the bite site thoroughly with mild soap and running water. Applying a clean, cold compress or an ice pack wrapped in a cloth can help reduce minor swelling or localized discomfort. Over-the-counter pain relievers or antihistamines can be used for mild, persistent irritation or itchiness. Medical attention is generally not required unless the bite area develops signs of a secondary bacterial infection, such as increasing warmth, spreading redness, or pus formation. Immediate medical help should only be sought in the extremely rare event of a severe allergic reaction, such as difficulty breathing or swelling of the face or throat.