To the Editor.
—The prevalence of silent thyroiditis (lymphocytic thyroiditis with spontaneously resolving hyperthyroidism) may become a controversy in clinical thyroidology. Nikolai et al1 found the disorder in 10% to 20% of their cases of hyperthyroidism. In a review of the subject, Woolf2 agreed that silent thyroiditis was relatively common, occurring in 3.6% to 23% of all cases of hyperthyroidism. However, Vitug and Goldman3 in a recent report in the Archives found only one case that fulfilled the criteria for diagnosis in a three-year review of 86 patients with hyperthyroidism encountered in their hospital.In 1983, I reported in a letter in the Archives that the disorder was very rare in my endocrine practice.4 I conducted a random poll of endocrinologists in Philadelphia and in several medical centers in the United States, and the universal opinion was that silent thyroiditis was indeed quite rare. The key