The majority of infants with cow's milk allergy can tolerate lactose, except when an enteropathy with secondary lactase deficiency is present.
Link to Publication: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726035/pdf/40413_2017_Article_173.pdf
Heine RG, et al. Lactose intolerance and gastrointestinal cow’s milk allergy in infants and children – common misconceptions revisited. World Allergy Organ J. 2017;10:41.