A dairy allergy is different than lactose intolerance, but is commonly confused with it because the symptoms are similar. If you experience nausea after you ingest dairy products, seek medical advice. A dairy allergy that causes nausea will be accompanied by other food allergy symptoms.
Cow’s milk is made of two main proteins: curd and whey. Whey protein makes up about 20 percent of cow's milk and curd is the remaining 80 percent. A person with a dairy allergy is allergic to one or both of the proteins in the milk, according to KidsHealth.org. The immune system overreacts to these proteins and attempts to fight them off by creating specific IgE antibodies that cause increased levels of histamine in the body. Histamine leads to the inflammation of soft tissue in the body, including the intestines, sinuses and lungs.
Nausea is the result of inflammation in the gastrointestinal tract. Nausea is accompanied by bloating, abdominal pain, gas, diarrhea and vomiting, according to MayoClinic.com. Nausea makes a patient feel queasy, leading to loss of appetite and food aversions.
According to the Kids Health website, other common symptoms of a milk allergy include skin reactions and respiratory tract complications. Skin reactions include bumpy rashes that are red and inflamed, such as hives or eczema. Skin reactions can lead to complications if the rash develops in the mouth, throat or inner ear. Respiratory tract symptoms include irritated eyes, sneezing, nasal congestion, a runny nose, postnasal drip, sinus headaches and asthma.
Most digestive issues caused by a milk allergy cannot be treated with medication. Once milk proteins are expelled from the body, digestive symptoms such as nausea will subside. Other minor symptoms can be treated with over-the-counter antihistamines. A severe allergic reaction may require immediate medical intervention with an epinephrine injection.
Nausea is also a common symptom of lactose intolerance. Lactose is a sugar found in cow’s milk. Lactose intolerance symptoms also include bloating, cramping and diarrhea.