An Approach to Disorders of Pigmentation

The document discussed disorders of pigmentation in veterinary dermatology, focusing on melanogenic pigmentation. It explained that melanin is synthesized in melanocytes, which are specialized cells in the hair follicle and epidermal basal layer. These cells form pigmentary functional units with keratinocytes, with each epidermal melanocyte associated with 36 keratinocytes, while bulbar melanocytes are linked to 4 cortical keratinocytes. Follicular melanocytes were noted for their cyclic activity, producing melanin during the anagen phase and undergoing apoptosis in the catagen phase. The chapter covered both hypopigmentation and hyperpigmentation disorders, providing diagnostic approaches and examples such as vitiligo, uveodermatological syndrome, Waardenburg syndrome, and lentigo simplex.