Beyond the Follicle: A Narrative Review on How Systemic Diseases and Drugs Affect Alopecia.

Alopecia is a multifactorial condition resulting from the convergence of systemic pathologies, pharmacologic exposures, genetic predispositions, and environmental factors. Among these, systemic diseases and medications play a prominent role by initiating biological cascades that disrupt follicular integrity. Systemic diseases and medications disrupt follicular homeostasis via mechanisms such as inflammation, oxidative stress, hormonal imbalance, and immune dysregulation. Endocrine disorders, metabolic syndromes, and nutritional deficiencies impair follicular function, while chemotherapeutics, antifungals, anticoagulants, and hormonal agents further compromise follicular cycling and stem cell viability. Understanding these mechanistic pathways is essential for predicting and mitigating drug-associated alopecia and informing targeted interventions. Precision medicine approaches that address systemic drivers while optimizing pharmacologic regimens are critical to preserving follicular integrity. Current treatments like minoxidil, platelet-rich plasma, and surgical restoration provide symptomatic relief but often fail to achieve lasting results. In contrast, emerging molecular therapies, including bioengineered exosomes, stem cell applications, and peptide-based formulations that target key signalling pathways and growth factors, hold promise for more regenerative and sustained hair restoration outcomes. Given the condition's complexity, a multidisciplinary framework integrating dermatology, endocrinology, immunology, and pharmacology is essential. Cross-specialty collaboration will be pivotal for advancing individualised, mechanism-driven care. Ultimately, accurate etiologic diagnosis remains the cornerstone of effective, tailored treatment strategies.