Medical Disclaimer
This guide is for informational purposes about pest identification and home management. Any suspected venomous spider bite should be evaluated by a medical professional. If symptoms are severe or progressing, seek emergency care immediately.
Brown Recluse (Loxosceles reclusa)
Missouri is within the core range of the brown recluse — the species is genuinely common here in a way it is not across most of the US. Brown recluse bites are rare despite the species' abundance because recluses are not aggressive and bites occur almost exclusively when the spider is compressed against skin — in a shoe, a clothing item from storage, or bedding disturbed during sleep.
Brown Recluse Bite Progression
Most brown recluse bites produce mild local reactions that resolve without medical treatment. A small minority of bites cause necrotic skin lesions — the tissue death that is the species' most serious medical concern. A significant bite initially presents as a mild red mark that may develop a pale center ring, followed over 24–72 hours by a developing blister and, in serious cases, an expanding necrotic zone. The key diagnostic feature is that progression is slow — days, not hours. Any rapidly expanding skin lesion is more likely MRSA or another bacterial infection than a spider bite, and MRSA is far more commonly the cause of suspected recluse bites than the spider itself.
Southern Black Widow (Latrodectus mactans)
The southern black widow is present throughout Missouri, most commonly in sheltered outdoor locations — under decking, in woodpiles, in outbuildings, and in undisturbed areas of basements and crawlspaces. Black widow bites cause systemic symptoms (latrodectism) rather than local tissue damage: muscle cramping, particularly abdominal cramping, sweating, nausea, and elevated blood pressure. The bite site itself may show minimal local reaction — two small puncture marks. Symptoms begin within 30–60 minutes and peak over several hours. Antivenom is available and effective; medical evaluation is warranted for any confirmed or suspected black widow bite. D&D Pest Control manages spider populations in Franklin County and rural Missouri — visit ddpestcontrolmo.com.