Korean J Dermatol.  2023 Jan;61(1):43-51.

The Prognosis of Post-Scabetic Itch

• Kim JC
• Chung BY
• Lee SY
• Park JS
• Kang SY
• Cho SI
• Park CW
• Kim HO

Abstract

Background
The primary goal of scabies treatment is to eliminate mites; however, but post-scabetic itch persists in many patients. Since long-standing itching can lead to the development of other comorbidities, appropriate interventions are necessary.
Objective
This study aimed to investigate the effects of inappropriate (continuous or prolonged) scabicide use and oral steroids on the duration of pruritus in patients with scabies.
Methods
The duration of pruritus, use of oral corticosteroids, total immunoglobulin E (IgE) levels, specific IgE levels for house dust mites, and eosinophil counts were evaluated. Post-scabetic itch was defined as itching that persisted for more than 3 weeks, although scabies was no longer detected; 208 participants with post-scabetic itch were included.
Results
We recruited 265 participants with confirmatory diagnosis of scabies and 116 with clinical diagnosis. We treated 124 participants with scabicides based on the guidelines, whereas 257 participants were not. The type of scabicide did not affect the duration of pruritus. Scabicide overuse did not shorten the duration of pruritus; however, its prolonged use lengthened the treatment period. Although oral corticosteroids did not shorten the duration of pruritus in the patients, they were effective when the patient had post-scabetic itch. In addition, a positive correlation between the total IgE level and duration of pruritus was observed.
Conclusion
This study investigated the effect of treatment modality on the clinical course of scabies. Our findings suggest that overuse of scabicides might be associated with post-scabetic itch, and short-term use of oral corticosteroids may be effective in reducing its duration.

Keyword

Prognosis; Pruritus; Scabies; Steroids; Therapeutics