Secondary Adrenal Insufficiency Exacerbated by Switching Inhaled Corticosteroids: A Case of Steroid Withdrawal Syndrome.

A 73-year-old man with severe asthma developed secondary adrenal insufficiency after long-term high-dose inhaled fluticasone therapy. Switching to inhaled ciclesonide worsened the symptoms (fatigue, muscle pain, diarrhea, and eosinophilia), and oral hydrocortisone had little effect. Reintroducing fluticasone rapidly improved the symptoms and normalized eosinophilia, suggesting that fluticasone may exert a uniquely strong individualized effect on the hypothalamic-pituitary-adrenal axis. Tapering requires prolonged management, but treatment with Saireito, a Kampo medicine, may have facilitated adrenal recovery. This case highlights that inhaled corticosteroids can significantly affect the systemic corticosteroid physiology, suggesting the need for careful monitoring when changing the preparations.