Hi..Thanks for the query. I assume the diagnosis was made for Scabies infection for your son.Scabies is an itchy skin condition caused by a mite called Sarcoptes scabiei. The presence of the mite leads to intense itching in the area of its burrows. The urge to scratch may be especially strong at night.Although any part can be affected, scabies is most commonly often found between fingers,armpit, waist,insides of wrists,inner elbow, buttocks,male genitalia. The confirmation of diagnosis is had by take a scraping from that area of affected skin to examine under a microscope. The microscopic examination can determine the presence of mites or their eggs.Medications commonly prescribed for scabies include: -Permethrin 5% cream /lotion: recommended applying twice, with a week or so between each application.Although these medications kill the mites promptly, you may find that the itching doesn t stop entirely for several weeks. - sometimes oral medication ivermectin is also prescribed alongwith. Because scabies spreads easily doctors recommend treatment for all family members and other close contacts, even if they show no signs of scabies infestation. Although 4 years is not very consistent with the diagnosis, I suggest you follow the above to eliminate scabies first and then review if still persistent. Hope this is helpful..Take care!