The pathophysiology of glossal pain in patients with iron deficiency and anemia.

Background: It is well known that prolonged anemia causes atrophy of tongue papillae, glossal pain, and dysphagia, but it is uncertain whether iron (Fe) deficiency induces glossal pain without any objective manifestation. To resolve this matter, the relationship between Fe deficiency and glossal pain was examined.
Methods: Eighteen patients with Fe deficiency and 7 anemic patients manifesting spontaneous irritation or pain of the tongue without any objective abnormalities participated in this study. To ascertain the cause of glossal pain and the oral pathophysiology in Fe deficiency and anemia, peripheral blood was examined and the glossal pain threshold and salivary flow rates (SFRs) were estimated along with Candida albicans cell culture tests.
Results: Compared with patients with Fe deficiency, those with anemia had a longer history of tongue pain. In patients with anemia, painful areas of the tongue were more numerous than in patients with Fe deficiency. Pain thresholds were decreased in the painful portions, and both nonstimulated and stimulated SFRs were suppressed. Each patient was treated with oral Fe; within 2 months, most patients exhibited increased serum ferritin level (P< 0.02, paired t-test), pain threshold (P < 0.05) and salivation (P < 0.05) and glossal pain subsided.
Conclusions: Fe deficiency causes glossal pain and the degree of glossal pain increases as Fe deficiency advances to anemia, manifesting hyposalivation and abnormalities of glossal papillae.