by Antony Ham Pong, MBBS
Dr. Ham-Pong is lecturer, Department of Pediatrics, University of Ottawa; consultant, Children's Hospital of Eastern Ontario; private practitioner.
Cow's milk allergy is very common and usually disappears by age two to three years, but may occasionally be lifelong. Children who are milk allergic will often refuse to take milk when given to them. Rashes, hives, vomiting or diarrhea are the most likely symptoms. Milk allergic people react to the milk protein, and not the milk sugar (lactose). There are many hidden sources of cow's milk protein. Three quarters of children with food allergies and eczema develop asthma and environmental allergies. This is called the 'allergic march'. First eczema beginning at age 6 weeks to 3 months, then food allergies, then asthma usually before age 5 years, then environmental allergies. The most common food allergies in young children are milk, eggs and peanut.
What can happen during an allergic reaction?
An allergic reaction to a food usually begins within minutes but may be delayed for 2-4 hours and usually lasts less than one day. The more severe the allergy, the smaller the amount required to cause a reaction. Typical immediate allergic reactions to foods include rash, hives or redness around the mouth, which may spread to the rest of the body, immediate runny nose, sneezing and itchy watery eyes, coughing, choking or gagging, wheezing and trouble breathing, and cramps, vomiting and diarrhea. The allergic reaction can stop at any stage, or may cause anaphylaxis. Anaphylaxis is a severe allergic reaction which involves several parts of the body and can lead to death.
Does milk or dairy have to be eaten to cause a reaction?
No. A food does not have to be eaten to cause an allergic reaction but eating it does cause greater amounts to get into the body and usually causes the most severe reactions. Hives can occur on skin contact with an allergenic food. If the food goes into the wet surfaces e.g., through a cut in the skin, or at the lips (e.g., being kissed by someone who has had milk), or in the eye (e.g., milk squirted in the eye) severe reactions can occur. The smell of a food can cause allergic reactions but not usually severe reactions unless there is an extremely high concentration. These lesser degrees of exposure by smell usually cause only minor allergic symptoms and discomfort e.g., itchy eyes or runny nose. High concentrations should be avoided e.g., being in the same room where milk sauces are cooking.
How cautious do we have to be about avoiding milk and dairy?
Many cow's milk allergic children tolerate small amounts of milk proteins in cooked or processed foods and do not need to restrict their diet severely. A child with a mild milk allergy or one who is outgrowing the allergy may tolerate small amounts of cheese, yogurt or milk formula but not plain milk. Children with severe milk allergy should avoid it strictly as even traces in cooked goods can cause allergic reactions and anaphylaxis (see Table 2). Milk allergic children have reacted to milk spilled on toys, bed sheets, etc.
Is milk/dairy always labelled?
No. There are many hidden sources of milk, dairy (see Table 1, 3). Milk and egg may be used as binders or fillers in foods e.g., bread, meat, fish, chicken. If these foods are then used to make another food or meal, the fillers do not have to be labelled even though that food may contain milk or egg. Natural flavours and seasonings are also terms to watch for as they can include milk proteins, soy, egg, even fish, and may be labelled only as natural flavourings or seasonings e.g., in tortilla or potato chips, canned and processed meats e.g., weiners & sausages, and fish. Beef allergy can sometimes occur with milk allergy, but usually with poorly cooked beef. Retail poultry may sometimes be treated with milk derivatives to enhance the texture. Hydrolyzed milk protein may also be added occasionally to hydrolysed vegetable plant protein and not be labelled.
How do you treat a milk allergy?
Avoidance of the milk is the best treatment. Degree of avoidance depends on the individual and the severity of the food allergy. Mild milk allergy may be treated by avoiding milk and dairy but being able to take trace amounts in cooked goods. For example, people with mild milk allergy can continue to take bread or cakes cooked with these foods in small amounts and do not have to be extremely strict about reading labels. However, even a mild food allergy can cause anaphylaxis if enough is eaten. Antihistamines such as Benadryl are usually sufficient to treat an allergy to milk. If you have breathing difficulties or anaphylaxis has been diagnosed, then an EpiPen® is required (this is an autoinjectable medication, epinephrine or adrenaline, which treats a severe allergy). Any person with potential anaphylaxis to a food should use their EpiPen® immediately when any reaction happens on eating that food, in order to prevent anaphylaxis. Cow's milk does not cause mucus in people not allergic to it and avoiding milk during asthma flare-ups, respiratory infections and in children prone to colds is of no value if you are not allergic to milk.
What can be used instead of milk?
Soy formula are often used for milk allergic children. If this is not tolerated, then special casein hydrolysate formulas e.g., Nutramigen, Pregestmil and Alimentum can be used (very few milk-allergic children react to these). Do not use goat's milk or lactose free cow's milk which will cause allergies as well. Lactose intolerant people are not milk allergic and can often take small amounts of milk without problems since their problem is digestive, not allergic. Note that soya milk is not soy formula and does not contain enough calories or calcium for an infant although it may be used as a drink for older children. However, there are some calcium enriched Soya milk and orange juices which provide extra calcium. Calcium supplements should be given to a young child who is not taking dairy or any other formula. All formulas including Soya formula contain sufficient calcium. Juices can be used if the child is on table foods, but too much fruit juice, especially apple juice, can cause bloating, cramps and diarrhea.
- Severe milk allergy: Can develop anaphylaxis with even small amounts: Strict avoidance of all traces of milk or dairy proteins and lactose. Consider keeping milk out of house. Use EpiPen® immediately with any reaction to eating of milk or dairy.
- Mild to moderate milk allergy:Small traces of dairy in cooked goods can be eaten unless it aggravates eczema; if so, avoid it. Lactose is OK. Avoid eating cream, cheese, yogurt, ice cream, milk.
- Very mild milk allergy: Will be outgrown soon. Can take small amounts of processed dairy e.g.,. cheese, yogurt.
What is cow's milk intolerance?
Cow's milk intolerance often causes delayed gastrointestinal symptoms, such as vomiting, diarrhea, colic and poor growth if untreated. Gastrointestinal reacting children can develop symptoms hours or days after ingestion of a modest amount of cow's milk (over 120 ml or 4 oz). Delayed gastrointestinal responses to cow's milk also can produce severe symptoms resembling anaphylactic shock although this is rare. Allergy tests in this type of intolerance are negative to milk, and these milk reactions usually do not cause eczema, hives, or breathing difficulties. Antihistamines do not work for these reactions. Milk intolerance often goes away by age 3 years. Strict milk avoidance is not necessary, and traces in baking can be eaten safely.
Lactose intolerance is not an allergy to milk or lactose. Lactose intolerance is an inherited deficiency of intestinal lactase enzyme which results in the milk sugar (lactose) remaining undigested in the gut, and then being fermented by gut bacteria to produce lactic acid. This causes bloating, gas, cramps and diarrhea, which often occurs several hours after ingestion of lactose. This is treated by substituting a lactose reduced milk (e.g., Lactaid milk) or taking lactase enzyme (Lactaid tablets) with milk products. Lactose intolerant people can often take small amounts of milk and lactose with no symptoms (usually up to 100 ml or 3 oz. cow's milk) and strict milk avoidance is unnecessary. Strict avoidance of lactose worsens the problem. Continued ingestion of lactose helps the gut continue to be able to digest some lactose.
EXAMPLE OF AN UNSAFE FOOD LABEL (but correct by current Canadian regulatory standards)
Corn, Vegetable oil, Colour, Cool Ranch seasoning, Salt, MSG
Actual food components
Corn, Vegetable oil, Tartrazine, Salt, MSG, Milk products, Cheese, Onion powder, Garlic powder, Tomato powder, Imitation Parsley, May contain caramel, annatto
* This product caused a severe allergic reaction in a milk allergic child.
TERMS INDICATING THE PRESENCE OF COW'S MILK PROTEINS
- Butter/ butter fat / buttermilk
- Lactaid milk / Lacteeze milk (tablets or drops are ok)
- cow's milk / dairy / pasteurized milk
- Lactalbumin / lactoglobulin / bovine scrum albumin
- milk formula/ whey / yogurt / ghee
- casein / sodium & calcium caseinate
- evaporated milk / skim milk
- hydrolysed casein / Rennet casein
- lactose free milk formula/ delactosed milk
- reduced allergenicity milk formula e.g., Goodstart
- Recaldent (milk casein derivative used in some Trident gum)
- cream / cheese / curds / sour cream / sour milk
- ice cream / milk solid / milk fat / ice milk
EXAMPLES OF FOODS TO BE CAUTIOUS ABOUT FOR MILK ALLERGY (I.E., MAY CONTAIN DAIRY)
|| cocoa, chocolate milk, milk shakes, malted milk, Orange Julius®, milkshakes, some calcium fortified orange drinks
|Bread & pastry with milk
||cake, cookies, pancakes, rolls, waffles, bread
||soy margarine usually has milk proteins; artificial butter flavour
||milk chocolate and caramels
|Cream sauces or cereals
||some processed meats, frankfurters, hot dogs, Vienna sausages, some poultry.
|"Non dairy" substitutes
||coffee whiteners e.g., Coffee-Mate® & Coffee-Rich®
||butter in crust or cream filling
||macaroni, spaghetti, custard, milk pudding, pet foods especially dog food
|Seasonings, natural flavours, binding agents, fillers
||some seasonings and natural flavours for meat & poultry; natural egg flavour, canned fish, seasoned & ranch style potato & tortilla chips, seasoned French fries
|Pareve (parve) foods & Kosher symbol "D. E."
||these may be contaminated with milk proteins due to shared manufacturing equipment
PRODUCTS WHICH MAY CONTAIN MILK PROTEINS
- tablets e.g., Claritin, Allegro, Reaction, Benadryl (use liquid preparation which are usually lactose free)
- indictable medications e.g., glucagon
- some dry powder asthma inhalers e.g., Ventodisk, Serevent diskhaler & diskus, Flovent diskus, Ventalin rotacaps, Foradil aerolizer capsules and Oxeze. Metered dose inhalers do not contain lactose.
MoRu-Viraten Berna Measles-Rubella vaccine - contains gelatin, lactalbumin & lactose but the standard measles, mumps & Rubella (MMR) vaccine do not.
Some diaper ointment, cow's milk & goat's milk shampoo, lactobacillus acidophilus capsules
Milk paint (used for country-look furniture)
(1) Lactose is purified from cow's milk and may contain trace impurities, including milk proteins. Pharmaceutical grade lactose is purer than food grade lactose. Individuals with cow's milk anaphylaxis may be prudent to avoid lactose in any form but those less severe allergy may be able to tolerate small amounts of milk protein in lactose.
FOODS OR TERMS WHICH ARE SAFE FOR COW'S MILK ALLERGY (1)
- lactic acid / lactulose / stearyl lactulate
- lactose (2, 3)
- beef (3) / gelatin (3) / oleo
- casein hydrolysate formula (3) (e.g., Nutramigen, Pregestimil, Alimentum)
- Corn or canola oil margarine (1) (e.g., Fleishmann's salt free, Lactantia light diet, Becel RSF calorie reduced, Canola Harvest low fat)
- nut butters
- peanut butter
- coconut milk
- soy milk / soy formula / cream of wheat/ rice milk
- cocoa butter
(1) Always read the label for hidden ingredients however.
(2) See discussion in Table 4.
(3) Usually safe but occasionally can cause allergic reactions in milk allergic individuals.
SUBSTITUTES FOR COW'S MILK ALLERGIC CHILDREN
- Soy formula (1)
- Casein hydrolysate formula e.g., Alimentum, Pregestimil, Nutramigen
- Amino acid derived formula e.g., Neocate
- Soy milk (2) / Rice milk (2)
- Meat based formula (not commercially available and not validated clinically)
(1) Soy allergy may coexist with cow's milk allergies in 8-14% of children and 25% of infants with cow's milk intolerance sensitive to soy.
(2) Not nutritionally complete, and not a substitute for formula, but useful for cooking and as a drink. Choose calcium fortified varieties.
|Age 1-3 years needs:
||500 mg elemental Calcium / day
e.g., 4 tsp Calcium Sandoz or 2-1/2 Turns antacids or
1 Calcium Sandoz Forte effervescent tablet ( 500 mg ) per day
|Age 4-6 years needs:
||600 mg elemental Calcium / day
e.g., 5 tsp Calcium Sandoz or 3 Turns antacid or
just over 1 Calcium Sandoz Forte effervescent tablets
( 500mg ).
or 1/2 tab Sandoz Gramcal (1000 mg tab)
Some calcium supplements are derived from cow's milk e.g., calcium lactobionate, and may contain trace impurities with milk proteins. This should be safe for cow's milk allergy except in the case of anaphylaxis when it should be avoided as a precaution.
Dolomite, bone meal or some other natural source calcium e.g., fossilized oyster shells may contain significant amounts of lead which exceed tolerable daily intakes for children, and should be avoided.
Calcium Sandoz, and some other liquid calcium supplements containing sorbitol as a sweetener, can cause osmotic diarrhea and abdominal cramps.