The patient is a 46,XY male infant born with marked undervirilization and mild transient glucocorticoid and mineralocorticoid abnormalities, to a mother treated with prolonged high dose vaginal nystatin. The nystatin use began at 8 weeks of gestation and continued until delivery at 31 weeks; the cumulative dose was much higher than the recommended safe dose. While the standard dose of nystatin for vaginal candidiasis is one application of 100,000 IU daily for 7–14 days, the patient’s mother used a total dose of over 6 million IU .
The degree of undervirilization noted in our patient suggested a defect in androgen production and/or action during fetal life. The cortisol level on cosyntropin testing although not robust, could be considered appropriate for the patient’s prematurity, size and antenatal steroid treatment prior to delivery. Although the elevated baseline and stimulated 17-OHP can be explained by prematurity, we have no explanation for the elevated DHEAS and 11-Deoxycortisol noted at birth which raised the possibility of mild, transient abnormalities in cytochrome P450 and CYP11B1 activities; genetic testing done at 5 months of life was however negative for all adrenal defects. Moreover, in 46,XY patients these enzymatic abnormalities do not cause undervirilization.
The initial 17-OHP level of 516 ng/dl (normal < 360 ng/dl) on DOL 1 may have been attenuated by the betamethasone administration 11 h prior to delivery. Due to restrictions with blood drawing, DHEA/Androstenedione ratio was not determined but the normal testosterone and DHT at birth made 3β-HSD deficiency unlikely; more so genetic testing was normal. The possibility of Cytochrome P450 Oxidoreductase (POR) deficiency was considered but the lack of associated skeletal abnormalities made it unlikely. Although microarray testing did not show any defects in the genes associated with adrenal or gonadal development, certain rare genetic abnormalities cannot be fully excluded. The possibility of a post zygotic mutation leading to mild androgen insensitivity cannot be 100% excluded. The evidence of normal mini puberty with interval phallic growth and the normal androgen receptor (AR) gene testing argue against androgen insensitivity as the cause of our patient’s severe undervirilization. The possibility of 5-alpha reductase (SRD5A2) deficiency was considered but was ruled out by the normal baseline and hCG stimulated testosterone / DHT ratio. Although no testing was done for a SF-1 mutation, the transient adrenal abnormalities, normal gonadotropins and testosterone levels, and appearance of the genitalia argue against this genetic mutation. The transient nature of P450 steroidogenesis disruption in adrenals and gonads as well as the normal T/DHT ratio strongly suggest that our patient’s undervirilization was due to factors other than genetic causes. We realize that although the patient’s initial adrenal steroid results were somewhat abnormal, they were not consistent with any type of congenital adrenal hyperplasia. Although congenital anatomic genital abnormalities are usually associated with other anatomic developmental defects (abdominal wall defect, cloacal exstrophy, renal anomaly) the possibility of an isolated genital abnormality cannot be completely ruled out. The normal response to cortrosyn after discontinuation of all medications support the transient nature of adrenal steroid abnormalities. Having received the baby on treatment and given his prematurity and size, we were not aggressive in weaning the medications and only completely discontinued them at 8 months.
We postulate that prolonged maternal treatment with high dose nystatin may have led to fetal exposure and interfered with the fetal production and/or action of testosterone and DHT only during the critical period of sexual differentiation along with mild disruption in some adrenal corticosteroid pathways still present at birth.
The abnormalities in our patient are similar to those reported after ketoconazole use; while ketoconazole inhibits fungal P450 14α-lanosterol demethylase preventing ergosterol synthesis, nystatin binds directly to ergosterol creating fungal cell wall pores leading to cell death [4, 5]. In humans, ketoconazole inhibits multiple adrenal and gonadal P450 enzymes and binds to the androgen receptor interfering with DHT action [1, 6]. Cholesterol is the essential precursor of steroidogenesis in adrenals and gonads. Evidence of adrenal insufficiency and genital ambiguity in Smith-Lemli-Opitz syndrome, an inborn error of cholesterol synthesis, underscores the importance of cholesterol in steroidogenesis . Nystatin was shown to bind to cholesterol in in vitro studies . The clinical abnormalities seen in our patient are similar but not identical to those caused by ketoconazole. It is possible that nystatin interferes with adrenal or gonadal steroidogenesis by an as yet unknown mechanism.
Population based case control studies indicated that the use of nystatin at 1.5–3 million IU orally for 3–6 days during the 3rd and 4th months of gestation was associated with hypospadias [2, 9].
While in most of these reports, infants were exposed to a single course of nystatin only during the first trimester; our patient was exposed to more than four times the recommended dose throughout pregnancy. Administration of nystatin in animals has been shown to cause oligospermia .
In addition to nystatin, Polygynax contains neomycin sulphate and polymyxin B. To our knowledge neomycin was not reported to cause any untoward effects on adrenal/gonadal steroidogenesis or to be associated with hypospadias. An in vitro study reported that polymyxin B acts as a partial ACTH agonist; this however does not explain the findings in our patient . Thus, it is possible that the prolonged and excessive maternal use of nystatin and subsequent fetal exposure may have caused the abnormalities in our patient.
We report severe fetal undervirilization and multiple steroidogenenic abnormalities in a 46,XY infant. All hormonal abnormalities were transient. It is of note that the androgen pathway, although severely affected in utero, had completely recovered at birth, while the corticoid pathway required a longer time to normalize. Based on the findings in our patient, literature reports of hypospadias in infants exposed in utero to nystatin and the known untoward effects of antifungals on steroidogenesis, we suggest that nystatin should be evaluated further for possible adrenal and androgen synthesis disruption.