A 34-year-old man presents to the office complaining of discomfort and itching in his perianal area that is more pronounced at night and has disturbed his sleep over the last two weeks. He denies any abdominal pain, diarrhea, pain on defection, or anal discharge. His other medical problems include severe gastroesophageal reflux disease and anxiety disorder. He was diagnosed with genital herpes two years ago and had taken daily valacyclovir for one year, but stopped 6 months ago. He has not had any recurrences over the last 18 months. He currently takes esomeprazole and alprazolam as needed. He lives with his wife and two children (ages 3 and 5) and claims to be monogamous.
His vital signs are within normal limits. Physical examination shows excoriations in the perianal region. The remainder of his examination is unremarkable.
Which of the following is the most likely cause of this patient's complaints?

Question

A 34-year-old man presents to the office complaining of discomfort and itching in his perianal area that is more pronounced at night and has disturbed his sleep over the last two weeks.  He denies any abdominal pain, diarrhea, pain on defection, or anal discharge.  His other medical problems include severe gastroesophageal reflux disease and anxiety disorder.  He was diagnosed with genital herpes two years ago and had taken daily valacyclovir for one year, but stopped 6 months ago.  He has not had any recurrences over the last 18 months.  He currently takes esomeprazole and alprazolam as needed.  He lives with his wife and two children (ages 3 and 5) and claims to be monogamous.
His vital signs are within normal limits.  Physical examination shows excoriations in the perianal region.  The remainder of his examination is unremarkable.
Which of the following is the most likely cause of this patient's complaints?

Quizplus · Accepted Answer

This patient's presentation is consistent with likely pinworm infection caused by Enterobius vermicularis. Pinworms typically lay their eggs on the perianal folds. Patients can spread eggs via autoinfection (anal scratching with hand contacting mouth), and to others by contaminating food or bed linens. The eggs hatch in the small intestine, and the larvae become adult worms within a month. The adult worm has a life span of 1-2 months, and can lay up to 10,000 eggs in the perianal skin folds (usually at night). Pinworm can be asymptomatic, but symptomatic patients present with nighttime anal pruritus. Significant infections can lead to secondary excoriations and bacterial superinfection. Diagnosis is made by placing clear cellophane tape on the anus ("scotch tape test") in the morning before defecation or bathing to retrieve the eggs, which are then detected by microscopic analysis. Pinworm commonly infects people living in close contact (e.g., entire household), and all dwelling members need treatment in addition to the symptomatic patient. Albendazole is the preferred treatment along with appropriate preventative measures (e.g., personal hygiene, washing linens). (Choice A) Anxiety disorder can present with GI symptoms including diarrhea, abdominal cramping, and excessive gas production. However, patients tend to have improved symptoms during sleep at night. (Choice B) Corynebacterium minutissimum is a gram positive bacillus that causes erythrasma, which can involve the genital area and cause chronic anal pruritus. However, erythrasma would likely also involve the interdigital (mainly between toes) and intertriginous areas (e.g., axilla, groin) and cause scaly skin. (Choice D) HSV presents more commonly with perianal ulcerations in immunocompromised patients and male patients with male sexual partners. Although this patient has had outbreaks of genital herpes in the past, he currently does not have any ulcerative anal lesions. In addition, HSV-associated pruritus does not correlate with a particular time of day. (Choice E) HPV can cause painless papular anal lesions that can become secondarily infected, but it usually does not cause pruritus. Educational objective: Enterobius vermicularis (pinworm) can present with anal pruritus and spreads easily through autoinfection or contaminated linens. Diagnosis is confirmed by microscopic analysis of perianally-placed clear cellophane tape. Albendazole is the preferred treatment along with preventative measures. __________ References: Prevalence of Enterobius vermicularis among preschool children in Gimhae-si, Gyeongsangnam-do, Korea (http://www.ncbi.nlm.nih.gov/pubmed/21738277) Characterization of Enterobius vermicularis in a human population, employing a molecular-based method from adhesive tape samples (http://www.ncbi.nlm.nih.gov/pubmed/21458560)

A 34-Year-Old Man Presents to the Office Complaining of Discomfort