From the Guidelines
No, promethazine is not sufficient to treat scabies. Scabies requires specific anti-parasitic medications such as permethrin 5% cream (first-line treatment), ivermectin (oral medication), or other scabicides like crotamiton or sulfur ointment, as recommended by the 2015 sexually transmitted diseases treatment guidelines 1. The standard treatment for scabies involves applying permethrin cream to the entire body from the neck down, leaving it on for 8-14 hours, then washing it off, and repeating the application after 7-10 days to kill newly hatched mites. Promethazine, being an antihistamine, can only help relieve itching associated with scabies but cannot kill the Sarcoptes scabiei mites that cause the infestation.
Some key considerations for managing scabies include:
- Treating all household members and close contacts simultaneously, even if asymptomatic, to prevent reinfestation
- Washing bedding, clothing, and towels in hot water and drying them on high heat to eliminate any mites, as outlined in the guidelines for managing scabies outbreaks 1
- Keeping fingernails closely trimmed to reduce injury from excessive scratching
- Considering ivermectin as an alternative treatment option in certain settings, such as institutional outbreaks, where topical scabicides may be less effective 1
Overall, while promethazine may provide some relief from itching, it is not a substitute for the specific anti-parasitic treatments required to effectively manage scabies.
From the Research
Treatment of Scabies
- Scabies is an ectoparasitic, highly contagious skin disease caused by a mite called Sarcoptes scabiei 2.
- The insecticides ivermectin and permethrin are commonly used for treatment of scabies 2, 3.
Efficacy of Permethrin and Ivermectin
- Twice application of permethrin with a 1-week interval is effective in 92.5% of patients, which increased to 94.2% after crossing over to the ivermectin group at a 4-week interval 2.
- A single dose of ivermectin provided a cure rate of 85.9% at a 2-week interval, which increased to 100% after crossing over to the permethrin group at a 4-week interval 2.
- Treatment with two applications of permethrin with a one week interval was effective in 96.9% of patients 4.
- Permethrin-treated patients recovered earlier than ivermectin-treated patients 2, 4.
Comparison of Topical Permethrin and Benzyl Benzoate
- Topical permethrin 5% demonstrated a lack of efficacy in the majority of scabies cases, whereas benzyl benzoate 25% demonstrated an excellent cure rate and reasonable tolerability 5.
- Treatment resulted in a dermoscopy-verified cure rate of 27% in the permethrin group and 87% in the benzyl benzoate group 5.
Use of Promethazine for Scabies
- There is no evidence to suggest that promethazine, an antihistamine, is sufficient to treat scabies 2, 3, 4, 5, 6.
- Promethazine may be used to relieve itching and other allergic symptoms associated with scabies, but it is not a primary treatment for the disease.