Perianal pseudoverrucous papules and nodules (PPPN) is an uncommon form of irritant contact dermatitis that can be easily confused with other conditions, leading to frequent misdiagnosis. The common inciting factor in all reported cases of PPPN is exposure to a persistent moist environment. A reactive epidermal hyperplasia resulting from moisture, heat, and chronic irritation is the most commonly proposed and likely pathogenic mechanism. Ammonia from urine may also play a contributing role.

PPPN has been described in patients with chronic urinary incontinence requiring diapers, encopresis, severe intractable diarrhea or chronic fecal incontinence secondary to spinal dysraphism, spina bifida, and spinal cord injury. PPPN typically occurs in infants or in patients with any of the above predisposing scenarios.

Related topic: pseudoverrucous irritant peristomal dermatitis