Risk factors for treatment failure in scabies: a cohort study. (4th March 2019)

• Record Type: Journal Article
• Authors: Aussy, A.; Houivet, E.; Hébert, V.; Colas‐Cailleux, H.; Laaengh, N.; Richard, C.; Ouvry, M.; Boulard, C.; Léger, S.; Litrowski, N.; Benichou, J.; Joly, P.
• Other Names: Bechu S. investigator.; Mion‐Mouton N. investigator.; Lafaurie O. investigator.; Barrel A. investigator.; Pulluard M. investigator.; Hamel V. investigator.; Dore M.X. investigator.; Duflo E. investigator.; Lardans‐Cassius S. investigator.; Rzeznik J.C. investigator.; Baricault S. investigator.
• Is Part Of: British journal of dermatology. Volume 180:Number 4(2019)
• Page Start: 888
• Page End: 893
• Publication Date: 2019-03-04
• Subjects: Dermatology -- Periodicals; Skin -- Diseases -- Periodicals; 616.5
• DOI: 10.1111/bjd.17348
• Languages: English
• ISSNs: 0007-0963

Abstract

Summary: Background: Treatment failure, which occurs in about one‐third of cases, is considered as a major factor in the increasing incidence of scabies in developed countries. Objectives: To identify predictors of treatment failure of scabies in ambulatory populations. Methods: This multicentre study compared the clinical characteristics and treatment modalities between a group of patients with scabies treated successfully and another group who were not cured 3 months after antiscabies treatment. Results: In total 210 patients with a diagnosis of scabies were included, comprising 98 patients in the treatment success group and 112 in the treatment failure group. The main risk factors for treatment failure were (i) the use of only one type of treatment, topical benzyl benzoate (BB) or oral ivermectin, vs. the combination of both treatments [odds ratio (OR) 2·15, 95% confidence interval (CI) 1·22–3·77]; (ii) the use of a single intake (vs. two) of oral ivermectin (OR 10·2. 95% CI 4·49–23·2); (iii) intake of ivermectin during a meal vs. on an empty stomach (OR 4·31, 95% CI 1·89–9·84); (iv) absence of decontamination of furnishings (OR 8·72, 95% CI 3·50–21·8), in particular sofa and cushions (OR 5·90, 95% CI 2·34–14·9), mattresses (OR 4·16, 95% CI 1·35–12·8) or car seats (OR 6·57, 95% CI 3·27–13·2) and (v) absence of written documents explaining treatment modalities (OR 5·18, 95% CI 2·57–10·4). In multivariate analysis, treatment failure was mainly associated with (i) use of a single intake (vs. two) of ivermectin (OR 6·62, 95% CI 2·71–16·2); (ii) use of BB alone vs. two intakes of ivermectin (OR 3·51, 95% CI 1·55–7·95) and (iii) absence of decontamination of furniture with acaricides (OR 5·81, 95% CI 1·96–16·7). Conclusions: Use of topical BB alone and a single intake (vs. two) of ivermectin are predictors of treatment failure. Abstract : What's already known about this topic? Scabies is a major public health problem worldwide. Developing countries account for the majority of cases, but an increasing incidence of scabies has been reported in developed countries. Treatment failure is considered a major factor in the increasing incidence of scabies in developed countries. Risk factors for antiscabies treatment failure, such as dementia and bedridden status, have been identified in hospitalized populations and are not relevant in ambulatory patients. What does this study add? This study, which was conducted in a large cohort of ambulatory patients, highlights several risk factors. A single intake of ivermectin is the major cause of treatment failure in scabies. The combination of one topical application of benzyl benzoate and two intakes of oral ivermectin results in the lowest rate of treatment failure. Not disinfecting fomites increases the risk of treatment failure. Linked Comment: Williams and Fuller. Br J Dermatol 2019; 180 :710–711 . Respond to this article Plain language summary available online