Enterobiasis household treatment — DTM&H MCQ

Correct answer: D — Treat all household members simultaneously

The correct answer is D, treat all household members simultaneously. Enterobius vermicularis (threadworm) has an autoinfection cycle and eggs remain viable on fomites, bedding, and under fingernails for days, so asymptomatic carriers in the same household continuously re-seed the index case if left untreated. NICE CKS on threadworm management advises that all household contacts be treated at the same time as the symptomatic patient, alongside strict hygiene measures for two weeks (handwashing, wearing pants at night, morning showering, and washing bedding and nightwear) to break the cycle of reinfection. The classic short history (perianal and vulval itch worse at night, visible thread-like worm at the anal verge) is diagnostic of enterobiasis and does not require further confirmatory testing before initiating this standard household-based approach. Why the other options are wrong: A. Treat the patient only and recheck in 2 weeks: this ignores asymptomatic household carriers who will simply reinfect the child, meaning the itch will recur regardless of a follow-up review. C. Perform stool culture to confirm the diagnosis: stool culture is not used for helminth diagnosis and threadworm eggs are rarely seen on routine stool microscopy; the sellotape (adhesive tape) test of the perianal skin is the correct confirmatory test if needed, but here the visible worm already makes diagnosis clinical. E. Prescribe long-term prophylactic anthelminthics: there is no guideline support for indefinite prophylaxis; standard treatment is a single dose (repeated at two weeks if needed) combined with hygiene, not ongoing prophylactic dosing. B. Screen the entire school with stool microscopy: mass school-based stool microscopy is impractical, low yield, and not the recommended public health response; the relevant transmission unit for simultaneous treatment is the household, not the whole school. Key point: Because threadworm eggs spread readily among close contacts, effective cure requires simultaneous treatment of the whole household plus two weeks of hygiene measures, not isolated treatment of the index patient.

Reference: NICE CKS, Threadworm: Management, https://cks.nice.org.uk/topics/threadworm/management/management/