Canine Congenital Hypotrichosis and Alopecia Study Guide

Overview and Clinical Importance

Congenital hypotrichosis and alopecia represent a group of hereditary skin disorders characterized by partial or complete absence of hair from birth or shortly thereafter. These conditions result from abnormal development, absence, or dysfunction of hair follicles during embryogenesis. While typically cosmetic conditions that do not affect overall health, they are clinically important for differential diagnosis, genetic counseling, and understanding of developmental dermatopathology.

The terminology is important: alopecia refers to complete absence of hair, while hypotrichosis describes a reduction in hair density compared to normal. These conditions can be generalized or patterned, and may involve structures beyond hair follicles when associated with ectodermal dysplasia syndromes.

Classification of Congenital Hypotrichosis and Alopecia

Congenital hair loss disorders in dogs can be classified based on their genetic basis, clinical presentation, and whether they involve only hair follicles or multiple ectodermal structures.