Comparison (lactose intolerance with cow's milk protein allergy (CMPA))

lactose intolerance - lactose intolerance results from a reduced capacity to digest lactose - a sugar

cow's milk protein allergy

Epidemiology

Congenital lactose intolerance is very rare

Primary lactose intolerance develops when levels of the enzyme lactase naturally reduce, which usually occurs after 3 years of age in some populations (for example, Africans and Asians)

Secondary lactose intolerance as a result of mucosal damage - most commonly following severe gastroenteritis. However secondary lactose intolerance may also occur secondary to epithelium damage caused by other gastroenterological diseases such as in coeliac disease and cow’s milk allergy

estimated that up to 4.9% of children suffer from cow’s milk protein allergy (CMPA) (5)

may be IgE mediated CMPA, non IgE mediated CMPA or mixed

General features

Lactose intolerance causes symptoms that only in the bowel, for example, abdominal pain, loating, flatus, and diarrhoea

Lactose intolerance does not cause vomiting or GORD (6)

Secondary lactose intolerance presents as a result of mucosal damage - usually following severe gastroenteritis.

Secondary lactose intolerance is temporary, as long as the gut damage can heal. When the cause of the damage to the gut is removed, the gut will heal, even if the baby is still fed breastmilk, or their usual formula.

Breastmilk contains lactose (as does any mammalian milk) and decreasing dairy intake in maternal diet does not alter the amount of lactose in breastmilk (6)

Estimated that fifty to sixty per cent of affected children have skin symptoms and/ or gastrointestinal symptoms and 20-30% have respiratory symptoms (4)

CMPA may be the underlying cause of gastro-oesophageal reflux disease (GORD) in up to 40% of infants and young children (4)

CMPA will resolve in 40-50% of infants by 1 year, 60-75% by 2 years and 85-90% by 3 years (4)

• however the natural history is actively changing, showing a definite trend to persist longer, especially the IgE-mediated clinical expression of CMPA (4)

Only about 10% of babies with CMPA will require an amino acid formula (AAF). The remainder should tolerate an extensively hydrolysed formula (EHF) (6)

10-14% of infant with CMPA will also react to soya proteins (and up to 50% of those with non-IgE mediated CMPA). But because of better palatability soya formula is worth considering in babies>6months (6)

lactose intolerance

IgE mediated cow's milk protein allergy

non-IgE mediated cow's milk protein allergy

Mechanism

Lactose intolerance results from a reduced capacity to digest lactose, a sugar

Congenital lactose intolerance

• very rare and presents only in isolated populations, for example, some families in Finland and Russia.

Primary lactose intolerance

• develops when levels of the enzyme lactase naturally reduce
• usually occurs after 3 years of age in some populations (for example, Africans and Asians)

Secondary lactose intolerance

• presents as a result of mucosal damage, usually following severe gastroenteritis but also when the epithelium is damaged such as in coeliac disease and cow’s milk allergy
  • usually reversible once the epithelial lining has repaired
  • children with suspected lactose intolerance do not usually require any testing and should improve within 48 hours on a low lactose diet
  • in secondary lactose intolerance, for example after severe gastroenteritis, lactose can usually be tolerated again by 6 weeks

Notes:

• except after a gastrointestinal infection, infants with gastrointestinal symptoms on exposure to cow’s milk are more likely to have cow’s milk allergy than lactose intolerance

IgE mediated allergic reaction to milk protein

• IgE-mediated reactions typically occur immediately after ingestion
• IgE-mediated reactions are immediate, requiring only a small quantity of food to be ingested, enabling rapid identification of the allergenic foods

Non-IgE mediated allergic reaction to milk protein

• non-IgE mediated are delayed and take up to 72 hours to develop, but still involve the immune system (4) - therefore the identification of suspect foods is often difficult. The mechanism is unclear, it is harder to diagnose and there are no validated tests to confirm such an allergic reaction
• symptoms of non-IgE mediated disease are commonly wrongly labelled as symptoms of intolerance, using either the terms 'lactose intolerance' or 'milk intolerance' (2)

Symptomatology

symptoms occur only in the bowel - for example, abdominal pain, bloating, flatus, and diarrhoea

lactose intolerance does not cause of rectal bleeding (which may occur in cow's milk allergy)

Possible dermatological features include:

• pruritus
• erythema
• acute urticaria (localised or generalised)
• acute angioedema (most commonly in the lips and
  face, and around the eye

Possible gastroenterological features incldue:

• agioedema of the lips, tongue, and palate
• oral pruritus
• nausea
• colicky abdominal pain
• vomiting
• diarrhoea

Respiratory system (usually in combination with one or more of the above symptoms and signs)

• upper respiratory tract symptoms (nasal itching,
  sneezing, rhinorrhoea, or congestion, with or without
  conjunctivitis)
• lower respiratory tract symptoms (cough, chest
  tightness, wheezing, or shortness of breath

Other

• sgns or symptoms of anaphylaxis or other systemic allergic reactions

Possible dermatological features include:

• pruritus
• erythema
• atopic eczema

Possible gastroenterological features include:

• gastro-oesophageal reflux disease
• loose or frequent stools
• bood and /or mucus in the stools
• abdominal pain
• infantile colic
• food refusal or aversion
• constipation
• perianal redness
• pallor and tiredness
• faltering growth plus one or more gastrointestinal symptoms above (with or without significant atopic eczema)

Tests

Exclusion diet (low lactose) (symptom improvement) and then reintroduction (symptom recurrence). Usually improve within 48 hours of exclusion

An infant with suspected IgE-mediated milk allergy will require testing for specific IgE to milk (skin prick test or blood tests) - iInfants with suspected non-IgE-mediated disease do not need these tests

Exclusion diet (No milk protein) (symptom improvement) and then reintroduction
(symptom recurrence). May take 4–6 weeks
for symptoms to improve (2)

Dietary advice
(including
formulas)

Low lactose diet - exclude cow’s milk and foods containing cow’s milk, although some with low lactose may be tolerated by some individuals If secondary, should resolve by 6 weeks

Managed via secondary care - a diet free from cow’s milk protein. Exclude all cow’s milk and products

Dietary management involves removing the allergenic protein from the diet

• all dairy products must be removed from the diet of a breastfeeding mother if milk allergy is suspected in the infant and calcium supplements given
• in a formula-fed infant, choice of formula is determined by the severity of the symptoms
  • most infants respond to extensively hydrolysed formulas, where the milk protein is broken down
  • amino acid formulas should be reserved for severe symptoms and those not responding to an extensively hydrolysed formula
    • should also be used first line if top-up feeds are required in an infant who is exclusively breast fed and shows symptoms suggestive of cow’s milk allergy
• acquisition of tolerance in cow’s milk allergy should be considered after at least 6 months on a diet free from milk protein
  • likely that tolerance to extensively baked milk products will occur before that to less well cooked milk

Refer to secondary care only if symptoms severe (4)