Milk allergy

Approximately 20% of children in Switzerland who have a food allergy have a reaction to milk. In adults the allergy is relatively rare. Cow’s milk protein allergy (CMPA), which involves the immune system, is completely different from lactose intolerance.

Triggers

The milk proteins responsible for the allergy can be roughly divided into two groups. Approximately 80% of the proteins in cow’s milk are caseins. The remaining 20% are the whey proteins alpha-lactalbumin and beta-lactoglobulin. Caseins are present in all animal milk, including that of goats, sheep and mares. Alpha-lactalbumin and beta-lactoglobulin can be found only in cow’s milk. Moreover, neither of the whey proteins are heat stable, which means that they break down at high temperatures.

Most sufferers do not have a reaction to just one specific milk protein. They usually cannot tolerate several allergens and must therefore avoid almost all types of animal milk. A few, however, only have a reaction to the alpha-lactalbumin and/or the beta-lactoglobulin and can therefore tolerate cooked or baked cow’s milk such as in cheese and yogurt as well as in a braid.

Presence

Cow’s milk is present not only in dairy products such as yogurt, cheese or curds but also in processed products such as biscuits and ice cream and is a hidden ingredient in salad sauces and sausage. With a cow’s milk allergy, sufferers may also have a reaction to the milk of other mammals such as sheep, goats and mares. Purchasing guide in German «Einkaufshilfe Milchallergie».

Course of the allergy

It is possible to outgrow cow’s milk allergy. Infants may thus be able to tolerate milk as they get older. An annual check with the treating specialist is therefore recommended.

Symptoms

With cow’s milk allergy, symptoms appear within minutes and to an hour after consumption and typically include itching in the mucous membranes of the mouth and on the skin with redness, wheals and swelling. Like other food allergies, respiratory symptoms may also occur. Isolated gastrointestinal symptoms are rare. They usually occur in combination with other allergy symptoms, such as difficulty swallowing, nausea, vomiting, diarrhoea and bloating. In rare cases, the allergy may result in anaphylactic shock with breathing difficulties and circulatory collapse.

Diagnosis

Self-monitoring – ideally recorded in a symptom diary – and a consultation with an allergy specialist, together with the results of skin and blood tests, are the essential basis for the diagnosis of cow’s milk allergy. To confirm the diagnosis and to determine the tolerance level, provocation (or challenge) tests may also be required.

Treatment

Strict avoidance of the food causing the allergy is essential. It is also essential to watch for concealed sources in bakery products, sausage, spice blends and semi-cooked and ready meals. If there is a risk of an anaphylactic reaction, it is essential to strictly avoid even the tiniest amounts (traces / contaminants). Whether traces can be tolerated should be decided by an allergy specialist. They may use a provocation or challenge test to determine the level of tolerance to the allergen.

A specialist dietician can provide helpful support in implementing treatment in daily life. For example, to discuss the use of milk substitutes, to learn how to read ingredient lists, to receive practical advice and to discuss possible changes to one’s personal daily life. The supply of essential nutrients (protein, vitamins and minerals) should be assessed by a specialist dietician and monitored by the treating paediatrician/doctor.

Anyone who has already suffered a severe allergic reaction should always carry an emergency medical ID card and an emergency kit to ensure prompt treatment of any further severe allergic reaction. In any event, once first aid has been administered, they should then seek medical attention from an emergency doctor or hospital.

Oral immunotherapy

Allergen-specific immunotherapy to cow’s milk allergy has been investigated in a number of studies. This involves participants regularly taking gradually increasing tiny amounts of milk under medical supervision so that the immune system gradually becomes accustomed to it. Some initial success has been achieved, but with a high number of undesirable effects, such as allergic reactions. The treatment is not yet generally available to sufferers in clinical practice. We strongly advise against attempting such treatment independently at home.

Labelling of food

The presence of milk in food must be declared in Switzerland and the EU. This means that the ingredient and any products produced from it are clearly labelled and highlighted on the packaging – for example, in bold type, italics or in capital letters. Allergy sufferers should look out for the following terms when buying food items: milk powder, whey, whey powder, milk protein, whey protein, casein, caseinate, lactalbumin, lacto…, skimmed milk, sweet whey and animal protein. Unintentional mixtures/combinations must also be mentioned at the end of the list as follows: “may contain …” or “may contain traces of …”. Sales staff in shops selling food (e.g. bakeries, butcher’s etc) and in restaurants, takeaway kiosks etc must also provide information. By law, information supplied verbally by a professional is adequate.

Tips and tricks

• Write the allergy-causing foods on a “visiting card” and hand to restaurant staff when ordering.
• Before holidays, have these cards translated into the local language and take them with you.
• When invited round to friends and family, either tell the hosts exactly about your allergy or offer to take something allergen-free with you.
• Check lists of ingredients of familiar foods before buying. The recipes can be changed at any time. If you are not sure, the manufacturers or wholesalers will be glad to provide information. Their contact details can be found on the packaging.
• When shopping, look out for products with the Allergy Seal of Quality, these are particularly suitable for people with allergies and intolerances and are recommended by aha! Swiss Allergy Centre.

Facts and figures

• Milk is one of the most common triggers of food allergy in children, especially between the ages of two and three.
• Milk is one of the primary triggers of anaphylactic reactions in children under the age of six.
• In adults, cow’s milk is the trigger in 8% of food allergy sufferers.

Milk allergy: FAQs

How can I ensure I have enough calcium in my diet if I have a milk allergy?

Some milk substitutes are fortified with calcium. Calcium rich mineral water can also substantially help cover the daily requirement. Following a consultation with a medical professional, a calcium supplement may also be beneficial.

Is heated mild better tolerated than raw milk?

Milk contains both heat sensitive and heat stable allergens. Depending on the allergen that triggers the allergic reaction, sufferers can tolerate milk when heated or baked to a high temperature. This should be tested only under medical supervision.

Is it safe for me to consume vegan products?

Products labelled as vegan may contain traces of milk. Whether they can be tolerated depends on the individual level of tolerance of the person concerned.

Must I give up milk for the rest of my life?

Milk protein allergies typically first occur in infancy and childhood and in most cases are outgrown by school age. An annual check with an allergy specialist is therefore recommended. In rare cases, adults may also develop a milk protein allergy. These adults must then give up milk completely and choose milk substitutes.

Can I use lactose free milk instead of cow’s milk?

No. Lactose free milk still contains the milk proteins that trigger a milk protein allergy.

Is it possible to become desensitised to milk protein?

Much research is currently being conducted on oral desensitisation to milk protein. The aim of the treatment is to gradually accustom the immune system to the protein, so that milk can be consumed without any allergy symptoms. The treatment is not yet generally available to sufferers in clinical practice. Under no circumstances should such a treatment be attempted independently at home.

Is there any link between lactic acid and milk?

None at all. Lactic acid is produced using lactic acid bacteria in starch – usually maize or potato starch – and contains no milk components. It is approved for use in the food industry as additive E270.

Editors: aha! Swiss Allergy Centre in co-operation with the Scientific Advisory Board. For prevalence figures, see source references.