Blue sclera: An overlooked finding of iron deficiency

A 46-year-old woman presented with a 3-month history of progressive fatigue and shortness of breath. She had a history of uterine fibroids with heavy menstrual bleeding but had missed her gynecologic follow-up examination 2 years earlier. Physical examination revealed facial and conjunctival rim pallor, blue sclera (Figure 1A) with conjunctival rim pallor, and koilonychia. Laboratory tests were hemoglobin 4.0 g/dL (reference range 12–16), hematocrit 16.7% (37–47), mean corpuscular volume 54.8 fL (80–98), serum ferritin 0.8 ng/mL (24–307), and transferrin saturation 2.8% (20%–50%). Iron deficiency anemia was diagnosed.

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Figure 1

(A) Bluish sclera with peculiar brilliancy and pale skin at presentation. (B) Normalized sclera color 3 months after iron supplementation therapy.

The patient received a blood transfusion and began taking iron supplements. Her uterine fibroids were treated with oral gonadotropin-releasing hormone antagonists. Three months later, her symptoms and physical findings, including the blue sclera (Figure 1B), had resolved, and her hemoglobin and ferritin levels had normalized.

Blue sclera is a common and useful finding of iron deficiency but is often overlooked. In 1908, Sir William Osler first described a blue discoloration of the sclera as a symptom of anemia in young girls and wrote that the eyes “have a peculiar brilliancy and the sclerotics are of a bluish color”.¹ Kalra et al² subsequently found that blue sclera is more common in patients with iron deficiency anemia (87%) than in those with other types of anemia (7%). In adult patients, blue sclera reportedly has 87% to 89% sensitivity and 64% to 94% specificity for iron deficiency anemia and iron deficiency (ie, anemia need not always be present).^2,3 Blue sclera has been reported in other conditions, albeit rarely, including rheumatoid arthritis, myasthenia gravis, and long-term steroid therapy.² Its pathogenesis is thought to involve thinning of the collagen fibers of the sclera due to iron deficiency, which allows the bluish color of the underlying uvea to become visible.

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