When the body produces immunoglobulin E (IgE) antibodies, in response to one or more proteins in the milk, be it casein or whey, then this adverse reaction is termed as milk allergy. The immune system of the body presumes that casein and whey proteins are foreign bodies and produces antibodies against them. The immune system fails to recognize milk proteins as harmless and aims at destroying them by producing antibodies. The immune system releases toxin-filled granules, through specialized cells into the blood and these toxins are the reason milk-allergic individuals suffer the symptoms, they are affected with.
Those who are allergic to casein protein are unable to tolerate boiled cow’s milk (casein is heat stable), whereas, those allergic to whey protein can consume boiled milk (whey can be broken down by heat). However, in most cases, people are allergic to both casein and whey, which is why milk-allergic individuals, cannot tolerate boiled milk at all. Milk allergy is seen to affect about 3-5% of infants across the globe, however, the relieving factor is that most children grow out of this allergy, by the age of 6 years. This allergy is mostly seen in children, but even adults can get affected (though the number of affected adults are few).
On the other hand, lactose intolerance is a condition characterized by the absence of lactase, an enzyme in the gastrointestinal tract, that is essential for the metabolism of lactose sugar present in milk. This condition is seen in children above the age of 5, unlike milk-allergic children who are seen to outgrow the allergy by this age. The reason behind this is that lactose intolerant children are born with lactase enzyme functioning in the right manner. However, after the age of 5, they lose this enzyme partially or completely and the reason is still unknown.
Symptoms of Milk Allergy
Symptoms of milk allergy vary from person to person, and adverse reactions can occur immediately after the consumption of cow’s milk or even after several hours or days. There are some cases, wherein, an allergy is developed after prolonged ingestion of milk. Milk allergy is categorized into three types:
Type 1: This type features those individuals who show adverse reactions immediately after ingestion of small volumes of cow’s milk. Their symptoms encompass reactions pertaining to the skin such as hives, eczema and so on. Gastrointestinal and respiratory symptoms may or may not be present.
Type 2: This type encompasses those individuals who develop milk allergy symptoms several hours after the ingestion of moderate amounts of cow’s milk. Their symptoms comprise vomiting and diarrhea.
Type 3: The third type encompasses those individuals, who develop symptoms 20 hours, or even days after the ingestion of considerable amount of cow’s milk. The symptom exhibited is diarrhea, which may or may not be accompanied by respiratory symptoms or skin allergies.
Milk allergy is observed to affect the skin, gastrointestinal tract and the respiratory system. The various symptoms that indicate milk allergy are:
- Hives, eczema and skin rashes
- Vomiting, abdominal pain and bloating
- Excessive colic and abdominal cramps
- Recurrent diarrhea
- Loose stools (which may contain blood or mucus)
- Coughing, sneezing and chronic runny nose
- Nasal stuffiness
- Wheezing and shortness of breath
- Swelling of the mouth, tongue, lips, throat or face
- Allergic shiners (blackness around the eyes), watery and itchy eyes
- Ear infections and fluid retention behind the ears
- Recurrent bronchitis
- Failure to thrive
- Irritability and hyperactive behavior
The above-mentioned symptoms are not restricted to milk allergic individuals, and are found in people with food allergies as well. Besides food allergies, these symptoms can be even seen as a result of any other immune reaction, such as a drug reaction to penicillin or even a simple mosquito bite. Total avoidance of milk proteins is the only 100% successful treatment of this condition. It’s a good thing that children grow out of this as they reach 5 to 6 years of age!