Cushing’s syndrome (CS) affects children in 10% of cases and is occasionally associated with the abuse of health-related products causing exogenous glucocorticoid (GC) excess. A 15-year-old girl presented with suspected CS: endogenous hypercortisolism and exposure to GC containing drugs were ruled out. She reported using an anti-lice foam for one year. After discontinuation, her clinical condition gradually and completely reversed. This study aims to investigate whether compounds, such as pyrethrins and piperonyl butoxide (PBO), contained in the anti-lice product have GC-like activity. Serum levels of pyrethrins and PBO in the patient and controls were measured by LC-MS/MS. To test whether PBO has GC-like effects, the GloResponse 9XGAL4UAS-luc2P HEK293 (GloHEK) cell line was incubated with PBO and luminescence (LUM) was measured. During anti-lice product exposure patient’s PBO serum levels were ~ 25-fold higher than control samples. Six months after product discontinuation, PBO levels in patient’s serum decreased to levels comparable to controls. PBO did not affect the viability of GloHEK cells at the concentration employed in the luciferase assay (10 µM). Baseline GloHEK cell LUM was significantly increased by PBO (> 7-fold; p < 0.01), an effect reversed by a GC antagonist. PBO contained in the anti-lice product has a GC-like transcriptional activity. These results support the hypothesis that CS signs and symptoms were related to anti-lice product exposure, causing a foam-induced Cushing. The use of pharmaceutical and non-pharmaceutical products should always be investigated in patients with CS.
Rossi et al. (2026) studied this question.