Hi & Welcome to HCM. I appreciate your concern for the recurring pinworm infestation. The following treatment and the prevention is recommended for pinworm infestation. A single oral dose of Mebendazole 100 mg (regardless of age) or Albendazole 400 mg, repeated in 2 weeks, is effective in eradication of pinworms. Carbolated petrolatum or other antipruritic creams or ointments applied to the perianal region may relieve itching. Reinfection can occur easily so; 1. All family members or classmates of your children must be treated simultaneously. 2. Personal and group hygiene must be improved: individuals must wash their hands before eating, and children should be discouraged from activities such as scratching the perianal area), finger-sucking, nail biting and their nails should be trimmed. 3. To reduce your risk of getting or spreading an infection, wash your hands thoroughly after having a bowel movement or changing a diaper and before eating. 4. Daily morning bathing and daily changing of underwear helps removes a large proportion of eggs. Showering is preferred to avoid possible contamination of bath water. 5. Careful handling and frequent changing of underclothing, night clothes, towels, and bedding can help reduce infection, reinfection, and environmental contamination with pinworm eggs. These items should be laundered in hot water, especially after each treatment of the infected person and after each usage of washcloths until infection is cleared. If you follow the preventive measures as described above the chances of reinfection will almost be zero. Hope to have answered your query. A feed back is appreciated.