Scabies is a widespread, contagious parasitic disease that affects all socioeconomic groups and was added to the list of WHO Neglected Tropical Diseases. Recent studies indicate misdiagnosis in 45% of patients with scabies. Crusted scabies is a rare, acute and highly contagious form of scabies infestation, mainly observed in patients with immunosuppression or mental illness. Standard therapy for crusted scabies is a combination of a topical scabicide and oral ivermectin. The aim of the study was to present the case of a 19-year-old male patient with Down syndrome and systemic disorders, who was diagnosed with crusted scabies and successfully treated with ivermectin. We suggest that ivermectin is an effective and safe therapy for crusted scabies treatment. The presented case shows the desirability of ivermectin registration for crusted scabies in Poland.