Retinoids Putting the 'A' in Alopecia

The document discusses the role of vitamin A (vitA) in hair loss conditions such as alopecia areata (AA) and cicatricial alopecia (CA). It highlights that vitA and vitamin D are important for immune responses and the growth of skin and hair. Retinoids, which are vitA-related compounds, have been used to treat various skin disorders and function by binding to nuclear receptors to regulate gene expression. The studies featured in the document show that genes involved in retinoid metabolism are upregulated in AA and that dietary vitA levels may influence the development of AA and CA. Mice with altered vitA diets showed varying effects on hair loss, immune cell infiltration, and follicle dystrophy. The findings suggest that nutritional factors, particularly vitA, may play a role in the pathogenesis of AA and CA, but the exact mechanisms are not fully understood and require further research. The interplay between genetics and environmental factors, such as nutrition, may affect the threshold for initiating and propagating these hair loss diseases. The document underscores the importance of considering the impact of retinoids and controlling for nutritional intake in research related to skin, hair, and epithelial disorders.