Serum Ferritin Levels: A Clinical Guide in Patients With Hair Loss

Although cutaneous manifestations of iron overload can be seen as skin hyperpigmentation due to increased iron deposits and increased melanin production,²² the effects of elevated ferritin on the skin and hair are not well known. Iron overload is a known trigger of porphyria cutanea tarda (PCT),⁵⁹ a condition in which reduced or absent enzymatic activity of uroporphyrinogen decarboxylase (UROD) leads to build up of toxic porphyrins in various organs.⁶⁰ In the skin, PCT manifests as a blistering photosensitive eruption that may resolve as dyspigmentation, scarring, and milia.⁶¹ Phlebotomy is first-line therapy in PCT to reduce serum iron and subsequent formation of UROD inhibitors, with guidelines suggesting discontinuation of phlebotomy when serum ferritin levels reach 20 ng/mL or lower.⁶⁰ Hyperferritinemia (serum ferritin >500 μg/L) is a common finding in several inflammatory disorders often accompanied by clinically apparent cutaneous symptoms such as adult-onset Still disease,⁶² hemophagocytic lymphohistiocytosis,^63,64 and anti-melanoma differentiation-associated gene 5 dermatomyositis.⁶⁵ Among these conditions, serum ferritin levels have been reported to correlate with disease activity, raising the question of whether ferritin is a bystander or a driver of the underlying pathology.^62,66,67 However, rapid decline of serum ferritin levels with treatment and control of inflammatory cytokines suggest that ferritin is unlikely to contribute to pathology.^62,67

Final Thoughts

Many clinical studies have examined the association between hair health and body iron status, the collective findings of which suggest that iron deficiency may be associated with TE. Among commonly measured serum iron parameters, low ferritin is a highly specific and sensitive marker for diagnosing iron deficiency. Serum ferritin may be a clinically useful tool for ruling out underlying iron deficiency in patients presenting with hair loss. Despite advances in our understanding of the molecular mechanisms of ferritin synthesis and regulation, whether ferritin itself contributes to cutaneous pathology is poorly understood.^35,36,68-74 For patients who are otherwise healthy with low suspicion for inflammatory disorders, chronic systemic illnesses, or malignancy, serum ferritin can be used as an indicator of body iron status. The workup for slightly elevated serum ferritin should be interpreted in the context of other laboratory findings and should be reassessed over time. Serum ferritin levels above 1000 μg/L warrant further investigation into causes such as iron overload conditions and underlying inflammatory conditions or malignancy.