However, the high cost of treating skin lesions using this when grafting donor sites are scarce is perfectly justifiable because of the decreased treatment duration,23,24 and also the better survival rates and the quality of the end result.25 Clinical reactions to collagen are rare, but two cases of allergy to bovine collagen, mediated by immunoglobulin E (IgE), have been reported. This evidence concerns the gene IGHE and allergic disease.