My daughter has swollen tonsils & a stuffy nose. it causes her to snore & occasionally stop breathing. could it be caused by a milk allergy?

Swollen tonsils: She is likely suffering from tonsillitis (viral in nature as she also has stuffy nose). I would recommend getting her swabbed for strep as it is easily treatable with antibiotics. Now her snoring and breathing definitely needs to be evaluated by her pediatrician - it may be due to large adenoids or tonsils and resulting in osa (obstructive sleep apnea).

Cold/Allergy: Common condition for a 3 yr. When get cold, there is nasal blockage due to swelling; sectetion make passage narrow, rubbing make worse. Child starts mouth breathing which causes dry mouth, tonsil involvement, snoring, sleep problem. Put saline nasal spray, blow nose gently, drink enough fluid. If too much runny nose: Benadryl (diphenhydramine) 1 teaspoonful x2/d. Milk can make more mucous, avoid for a week.

Nasal congestion: You do not mention how long this condition has been going on, does it come and go or is it constant? Milk allergy may not cause such issues on a chronic basis, and is associated with other symptoms such as abdominal pain, diarhhea, cramping and maybe hives or eczema. If this is chronic, she should see an ENT as her sleep apnea is concerning.