If you suspect that milk or a certain food is making your baby feel unwell or react suddenly, it can be quite unsettling to begin with. But there’s a helpful way to tell the difference between a food allergy and a food intolerance and that’s how quickly the reaction takes place.

With an allergy, the signs are usually there within minutes or seconds. An allergy is when the immune system gets a bit confused by reacting to an allergen in the food and builds up antibodies to attack it. The body releases defence chemicals, which cause an allergic reaction such as sneezing, swelling or a rash. It’s important you get your doctor to diagnose an allergy if you suspect one.

With an intolerance, the symptoms might be similar but the reaction usually takes longer and doesn’t involve the immune system. Upset tummies are often the main complaint.

Milk and food allergies are increasingly common, so you’re not on your own. Keeping a diary of what you give your baby can help you spot where the problem lies and only offering a new food every four days during weaning will help you spot any new reaction. An intolerance can be harder to diagnose. In either case, the best thing is to contact your doctor for an appointment, who will help to diagnose the problem and give you advice on how to manage it. If your baby is less than a year old, why not try our Baby Symptom Checker? It will give you useful advice and practical tips, and gives you a summary of your baby's symptoms to discuss with your healthcare professional.