National Study on the Epidemiology and Effectiveness of Therapies in the Treatment of Scabies

Scabies is an infectious skin condition caused by the mite Sarcoptes scabiei var. hominis. This mite can only parasitise and reproduce in the outermost layer of human skin (the stratum corneum). The disease is typically transmitted through human-to-human contact, though it can also be transmitted through fomites. It affects between 200 and 300 million people worldwide each year, with considerable variation in prevalence ranging from 0.2% to 71.4% in different regions. Over the past 10-20 years, the frequency of epidemics appears to be increasing, not only in countries where scabies is prevalent, but also in states that have historically experienced low rates of infection.The increase in cases across Europe, coupled with the rapid epidemic spread of the disease and the emergence of resistance to topical treatments, underscores the imperative for a comprehensive and systematic study involving multiple centres.

The primary guidelines for managing scabies involve performing environmental hygiene measures, such as washing and changing clothing daily and cleaning all surfaces that come into contact with the skin.

In terms of treatment, the European Society of Dermatology and Venereology guidelines recommend topical permethrin or benzyl benzoate and oral ivermectin as first-line treatments.

Apply topical permethrin 5% cream in the evening to cool, dry skin all over your body, including the folds, navel, limbs, genitals, the area behind your ears and under your nails. If there are any suspicious lesions, the scalp and face should also be treated, avoiding the areas around the eyes and lips. Leave the cream in place for 8-12 hours and apply a second dose after 7-14 days.

Oral ivermectin should be taken as a single dose at a dosage of 200 μg/kg, repeated in the same manner after seven days. Although European guidelines recommend taking it on a full stomach, the manufacturer and other guidelines recommend taking it on an empty stomach.

Benzyl benzoate lotion at a concentration of 10-25% is applied for two evenings and left in place for 8-12 hours. A third application should be made after seven days.

The treatment should be carried out not only by the patient, but also by their close contacts - usually members of their household - and should be extended to anyone who has had prolonged and continuous contact with individuals who are ill.

Topical permethrin cream at 5% is the first-line treatment for scabies in Italy. However, there has recently been an increase in reports of treatment failure. This phenomenon has also become increasingly prevalent in many other European countries. Therapy failure is likely to be due to a combination of factors, including drug resistance. Incorrect use of the treatment in terms of the amount of active ingredient, the method of application and/or the timing could be the cause of treatment failure.

The increase in cases in Europe, the rapid spread of the disease and the growing phenomenon of treatment resistance highlight the need for a large, systematic study involving several centres. Therefore, we propose a national multicentre retrospective and prospective observational study that aims to evaluate epidemiological data (prevalence, incidence, affected ethnicities and population groups), the most frequently used treatments, and treatment failures.

This study aims to evaluate the success rate of first-line therapies according to European guidelines in patients diagnosed with scabies and their close contacts (family members/caregivers). This will be achieved by observing patients with scabies who attend outpatient clinics for diagnosis, treatment and/or follow-up.