A 1.5 year male child presented with recurrent lesions for last 4 months. Lesions are nodular and itchy. No other family members are affected. Trial of anti scabies and anti allergic therapy has been given.

Local antibiotic cream has been also prescribed. General measures like through washing of all bedsheets and linens has been done. For brief period lesions did disappeared but have come up again. What could be the cause?