Laboratory Testing in Telogen Effluvium

The document from December 2020, "Laboratory Testing in Telogen Effluvium", discussed the limited evidence supporting the use of five common serum laboratory tests in managing Telogen effluvium (TE), a common cause of non-scarring hair loss. The tests examined were for ferritin, iron deficiency anemia, vitamin D, thyroid stimulating hormone, and zinc. The document highlighted that while iron deficiency and low ferritin levels have been associated with TE, controlled studies have not shown a significant difference in ferritin values or that iron supplementation leads to hair regrowth. Similarly, while some small, uncontrolled studies showed high rates of anemia among TE patients, a major controlled study found no difference in hemoglobin levels. The role of vitamin D in TE was unclear, with contrasting studies on the impact of supplementation. The document also noted that thyroid disease is often listed as a cause of hair loss, but treatment for hypothyroidism did not stop hair shedding in a study of chronic TE patients. Lastly, a small case series suggested that zinc supplementation could increase hair growth in TE patients, but the sample size was too small for definitive conclusions. The document concluded by emphasizing the need for more controlled studies and clinical trials to provide evidence-based care for TE.