Exposure to specific medication and abuse of some substances is another possible cause (tetracycline, minocycline, doxycycline, nalidixic acid, vitamin A excess and retinoids, isotretinoin, lithium, chlordecone), but also some endocrine dysfunction (related to human growth hormone, thyroxine—in children, Addison disease, hypoparathyroidism, anabolic steroids, but also withdrawal from chronic steroid treatment). This evidence concerns the gene GH1 and primary adrenal insufficiency.