What could i do to find out if i'm allergic to dairy or intolerant to it?

Dose & symptoms: With milk (lactose) intolerance, symptoms of gas, stomach pain, diarrhea occur 30 min to 2 hours after ingestion and symptoms worsen with higher amounts. With milk protein (casein, whey) allergy symptoms can be GI but frequently are hives, itching, swelling, occurring within minutes or worsening eczema. Symptoms can occur with tiny amounts. An allergy skin or blood test can confirm allergy.