Effects of potassium iodide in concentrations of TSH,tT3 and tT4 in serum of subjects with sporotrichosis

The saturated potassium iodide solution (SSKI) as treatment for sporotrichosis may cause hypothyroidism by suppressing the synthesis of thyroid hormones (tT₃ and tT₄) and the iodine excess could lead to thyrotoxicosis. Evaluating the changes in serum levels of TSH, tT3 and tT4 in euthyroid patients with sporotrichosis treated with SSKI. For the selection of euthyroid patients, TSH, tT₃ and tT₄ concentrations were measured for those adults and children diagnosed with sporotrichosis. Each paediatric patient was administered SSKI orally in increasing doses of 2–20 drops/3 times/day and 4–40 drops/3 times/day in adults. Serum concentrations of TSH, tT₃ and tT₄ were measured 20 days after started the treatment and 15 days posttreatment. Eight euthyroid patients aged between 2 to 65 years old were included. After 20 days of treatment, two suffered subclinical hypothyroidism, one developed subclinical hyperthyroidism, and one hyperthyroxinaemia euthyroid. At 15 days posttreatment only four patients were evaluated and all serum levels of TSH, tT₃ and tT₄ were normal. Some euthyroid patients with sporotrichosis can develop hyperthyroidism or subclinical iodine‐induced hypothyroidism, during the administration of 3 or 6 g SSKI/day.