A 25-year-old reports bloating and watery diarrhea 30–60 minutes after drinking a glass of regular milk but no hives, respiratory symptoms, or systemic reactions. Which management plan is most appropriate to recommend initially?

Advise strict lifelong avoidance of all dairy proteins and prescribe epinephrine auto-injector since these GI symptoms indicate IgE-mediated milk allergy, which misinterprets intolerance symptoms as anaphylaxis risk without allergic features.

Recommend a high-lactose diet to desensitize the gut microbiome immediately without any graded approach or supplements, a strategy that may worsen symptoms and lacks evidence as first-line management.

Suggest immediate colonoscopy and biopsy to look for lactase-producing tumors in the colon before any dietary changes, an invasive and inappropriate first step for typical lactose intolerance symptoms.

Recommend trial of lactose-free dairy alternatives or over-the-counter lactase enzyme supplement taken with milk and monitor symptom improvement to distinguish lactose intolerance from other causes.