Occasionally, an infant may suffer from one of the following feeding problems, which may require the use of a specialist formula milk:

Cow's milk intolerance

This is caused by an allergy to the proteins found in cow's milk. Symptoms may include nausea, vomiting, diarrhoea, asthma, eczema and urticaria (skin rashes). It is a condition that must be diagnosed by a doctor or allergy specialist.

The treatment is usually to avoid cow's milk and cow's milk products. This includes foods such as cheese, yoghurt, ice cream, chocolate, butter and cream. Milk constituents may also be found in biscuits, sweets and other processed foods.

Hypoallergenic hydrolysed protein formulas (example: Nutramigen 1 with LGG) are suitable for infants with cow's milk protein allergy, as are soya-based formulas (example: SMA Wysoy).

Lactose intolerance

Primary lactose intolerance is a rare, irreversible condition where children are born with the inability to produce lactase €“ the enzyme responsible for digesting lactose, the sugar in milk. Symptoms may include wind, bloating, abdominal pain, diarrhoea and crying.

Secondary lactose intolerance is a reversible condition in which the gastrointestinal tract stops producing lactase temporarily. It sometimes occurs after a bout of gastroenteritis.

Lactose-free formulas (examples: Enfamil O-Lac, SMA LF) can be used if a lactose intolerance has been diagnosed by a doctor.

Reflux

In reflux, the contents of the stomach return back into the oesophagus after feeding. Sometimes feed will come back up into the baby's mouth €“ this is known as regurgitation. This may occur because a baby's digestive system is immature and still developing.

It is a common concern and although it usually causes few clinical problems, it can be accompanied by crying and irritability and might make parents anxious.

New guidance from the National Institute for Health and Care Excellence (NICE) advises the following:

• If breastfeeding, a healthcare professional should review mum's technique
• If formula feeding, a healthcare professional should review the baby's feeding history and then reduce the volume of milk, if excessive for the infant's weight. A trial of smaller, frequent feeds can be offered if appropriate followed by a trial of thickened formula milk.

There are formula milks specifically designed to help milk settle in a baby's stomach, reducing the incidence and symptoms of reflux (example: SMA Staydown).