lactose intolerance(late onset)

Last edited 03/2020

The onset of this condition is several years after birth.

This condition is more common in some races than others, for example 10% of white Americans but 70% of black Americans develop moderate symptoms of lactose intolerance in adulthood when challenged with oral lactose

  • usually occurs after 3 years of age in some populations (for example, Africans and Asians) (2)

Clinical features may vary widely but in the most severe instances include chronic diarrhoea, abdominal pain, and distension after ingestion of lactose.

Adults and children may learn to adjust their diets so that the amount of dietary lactose is not greater than they can tolerate.


  • 1. Wilson J. Milk Intolerance: Lactose Intolerance and Cow's Milk Protein Allergy. Newborn and Infant Nursing Reviews 2005; 5 (4): 203-207.
  • 2. Walsh J et al. Differentiating milk allergy (IgE and non-IgE mediated) from lactose intolerance: understanding the underlying mechanisms and presentations. Br J Gen Pract 2016; DOI: 10.3399/bjgp16X686521