Because canker sores are immune-mediated and stress is a recognized trigger: in genetically susceptible people (up to 46% have family history), a T-cell-driven attack on the mouth's soft lining produces the ulcer - and StatPearls lists stress alongside trauma and iron, folate, B12, and zinc deficiency as linked factors.
The mechanism is not fully mapped, but the stress-sore pattern is consistent enough to be clinical consensus. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper .
What to do
Common questions
Why do I get canker sores when stressed?
Because canker sores are an immune-mediated condition, and stress is one of its recognized triggers - your observation matches the clinical literature. Recurrent aphthous stomatitis works like this: in genetically susceptible people (up to 46% report family history), the immune system attacks the mouth's soft lining - a T-cell-driven inflammatory reaction, with TNF-alpha calling in the neutrophils, that ends in a punched-out painful ulcer on the non-keratinized tissue: inner lips, cheeks, tongue. StatPearls lists stress alongside local trauma, smoking cessation, and iron, folate, B12, or zinc deficiency as linked factors. The stress mechanism is not fully mapped, but the pattern is consistent enough that clinicians treat a stress-sore link as real. What helps: topical corticosteroids are first-line (prescription pastes like triamcinolone dental paste beat anything OTC), salt-water rinses for comfort, avoid acidic and abrasive foods during a flare, and most ulcers heal in 1 to 2 weeks on their own. The flags that change the meaning: sores lasting past 3 weeks, arriving with genital ulcers or eye inflammation, or constant recurrence - those patterns point toward B12/iron deficiency, celiac, or rarely Behcet's, and deserve a workup.