Is there a really resistance to scabies treatment with permethrin? In vitro killing activity of permethrin on Sarcoptes scabiei from patients with resistant scabies

Recently, there have been increased scabies infestations but many patients do not respond to treatment. Clinicians are hesitant to use permethrin despite the fact that treatment failure may be due to noncompliance with the treatment rather than permethrin resistance. We aimed to investigate the permethrin resistance of mites collected from patients who have endured scabies for at least 3 months despite permethrin treatment. Parasites in patients who had scabies for at least 3 months despite permethrin treatment were collected. Only parasites that were not damaged during sampling, not fragmented and had full motion were included. Parasites were divided into four groups, each with 15 parasites. Immersion oil was dripped on the control group and 5%, 7%, and 10% permethrin was added to the study groups. The responses of the parasites to the applied agents were examined using a digital microscope. All solutions, except the control group, killed the scabies mite. The mean survival time (ST) in the 5%, 7%, and 10% permethrin groups was 360 ± 33.2, 340 ± 31.4, and 320 ± 30.2 min, respectively. There was no statistically significant difference in the mean ST in the permethrin groups. The mean ST in the control group was 46 ± 1.5 h. The mean ST difference between the control and permethrin-treated groups was significant (p = 0.03). There was no resistance to permethrin, which should maintain its place as first line treatment of scabies. Treatment noncompliance, rather than permethrin resistance, seems to be the underlying factor in the chronicity of scabies.