Yellow Sac Spider in NH: ID, Bite & When to Worry

The yellow sac spider is likely the spider most responsible for the reported 'spider bites' that aren't from a recluse or widow — because it actually bites. Cheiracanthium mildei, the indoor species common across New Hampshire, is a nocturnal hunter that moves freely across walls and ceilings at night, occasionally dropping into bedding or crawling into clothing left on the floor, where it gets trapped and bites defensively. The bite is immediate, real, and painful — no dismissing it. But the medical picture is far milder than most online accounts suggest.

Studies that examined confirmed Cheiracanthium bites — cases where the spider was captured, identified, and the victim's outcome documented — found only local effects: pain, redness, a raised wheal similar to a bee sting, resolving within hours to roughly 48 hours. No case in the verified-bite literature produced necrosis. The necrosis myth attached to sac spiders arose because many 'recluse bites' later proved to be sac spider bites or had other causes entirely — and the dramatic descriptions stuck.

In New Hampshire, the brown recluse is not established. If you were bitten by an unidentified spider in NH, it was almost certainly not a recluse. The yellow sac spider is the most likely candidate. This page gives you the honest picture: a real bite that deserves real attention, calibrated to what verified evidence shows — and clear guidance on when the bite warrants a doctor.