A painless spider bite that becomes a hemorrhagic blister is likely from which spider?

The brown recluse spider is known for its distinctive bite that often goes unnoticed initially, leading to a subsequent reaction that can include a hemorrhagic blister. This spider produces a venom that contains various enzymes and proteins, which can cause necrosis and other tissue damage. As a result, the bite may evolve from an asymptomatic state to one featuring significant local necrosis, blistering, and even ulceration.

The characteristic signs of a brown recluse bite include a necrotic center surrounded by erythema, and it tends to be painless or have minimal pain initially, which aligns with the situation described in the question. The potential severity of the bite can vary but often requires medical attention, especially if necrosis or significant systemic symptoms develop.

In contrast, other spider bites, like those from the black widow, typically present with painful muscle cramps and systemic symptoms rather than a blister. Jumping spiders and wolf spiders may cause localized pain or swelling but are not associated with the development of hemorrhagic blisters. Thus, the symptoms and progression outlined in the question are most consistent with the effects of a brown recluse spider bite.