Colour Dilution Alopecia (CDA) in Ten yorkshire Terriers

The study investigated Colour Dilution Alopecia (CDA) in 10 Yorkshire Terriers through clinical laboratory tests, light and electron microscopy, and X-ray microanalysis of skin biopsies and hair. It found a significant reduction in melanin in affected hair, with melanin clumps primarily in the epidermal basal layer, hair bulb, and shaft. Ultrastructural analysis showed basal keratinocytes overloaded with melanized melanosomes, disrupting cytoplasmic structures, and free melanosomes present in all skin layers. Scanning electron microscopy revealed holes and bulges in the hair shaft, while X-ray microanalysis identified silicate particles in superficial cuticular holes and calcium in deeper layers. These findings led to a new hypothesis on the pathogenetic mechanisms of alopecia.