Control of human scabies by topical application of ivermectin

Scabies in healthcare settings

PURPOSE OF REVIEW

In industrialized countries, epidemics of scabies are mainly described within families or in institutions such as healthcare settings. Control of institutional scabies is associated with a considerable working and economic burden, but guidelines for the management are scarce.

RECENT FINDINGS

The prevalence of institutional scabies is probably underestimated. Identified risk factors for institutional scabies outbreaks include the institution type, extensive physical contact with patients and movement of patients, the existence of crusted scabies, a long diagnostic delay and failures in implementation of infection control or treatment plans.Atypical clinical features (hyperinfestation, scabies in the elderly or in children) may be misdiagnosed. Control of institutional scabies outbreaks relies on prompt recognition of the index case, constitution of an outbreak management team, determination of the extent of the outbreak and risk factors for spread, immediate implementation of infection control practices, adequate education of all involved persons, simultaneous treatment of cases and of all exposed individuals and concomitant environmental disinfection. Prolonged surveillance is imperative to eradicate scabies.

SUMMARY

The inclusion of institutionalized patients in randomized controlled trials would be beneficial as present data concerning scabicide effectiveness are obtained from trials that recruited individual participants and do not take into account a global strategy.

Interventions for treating scabies

BACKGROUND

Scabies is an intensely itchy parasitic infection of the skin caused by the Sarcoptes scabiei mite. It is a common public health problem with an estimated global prevalence of 300 million cases. Serious adverse effects have been reported for some drugs used to treat scabies.

OBJECTIVES

To evaluate topical and systemic drugs for treating scabies.

SEARCH STRATEGY

In February 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE, EMBASE, LILACS, and INDMED. In March 2007, we also searched the grey literature and sources for registered trials. We also checked the reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials of drug treatments for scabies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Results were presented as relative risks with 95% confidence intervals and data combined where appropriate.

MAIN RESULTS

Twenty small trials involving 2392 people were included. One trial was placebo controlled, 16 compared two or more drug treatments, two compared treatment regimens, and one compared different drug vehicles.Fewer treatment failures occurred by day seven with oral ivermectin in one small trial (55 participants). Topical permethrin appeared more effective than oral ivermectin (85 participants, 1 trial), topical crotamiton (194 participants, 2 trials), and topical lindane (753 participants, 5 trials). Permethrin also appeared more effective in reducing itch persistence than either crotamiton (94 participants, 1 trial) or lindane (490 participants, 2 trials). One small trial did not detect a difference between permethrin (a synthetic pyrethroid) and a natural pyrethrin-based topical treatment (40 participants). No significant difference was detected in the number of treatment failures between crotamiton and lindane (100 participants, 1 trial), lindane and sulfur (68 participants, 1 trial), benzyl benzoate and sulfur (158 participants, 1 trial), and benzyl benzoate and natural synergized pyrethrins (240 participants, 1 trial); all were topical treatments. No trials of malathion were identified. No serious adverse events were reported. A number of trials reported skin reactions in participants randomized to topical treatments. There were occasional reports of headache, abdominal pain, diarrhoea, vomiting, and hypotension.

AUTHORS' CONCLUSIONS

Topical permethrin appears to be the most effective treatment for scabies. Ivermectin appears to be an effective oral treatment. More research is needed on the effectiveness of malathion, particularly when compared to permethrin, and on the management of scabies in an institutional setting and at a community level.

Scabies and Pediculosis Pubis: An Update of Treatment Regimens and General Review

Ectoparasites continue to be a common cause of skin disease throughout the world. The present article dissects the epidemiological profile and treatment of both Sarcoptes scabiei variant hominis and pediculosis pubis.