ARTICLE
Scabies, unfortunately, is still a problem in Italy. Mass tourism and
immigration are the main causes of the diffusion of the parasite in our
country. Current topical treatments are impractical, not very efficient
and irritating. For such reasons, we considered the experimental use of
ivermectin, the only oral therapy presently available for this disease.
Ivermectin is similar in structure to a macrolide antibiotic, but without
antibiotic activity. It is extremely effective against nematodes and mites
[1]. Moreover the 10-year history of the use of oral ivermectin to control
endemic onchocerciasis indicates that it is an extremely safe drug. For
the aforementioned reasons, in 1992, it was proposed for the treatment
of human scabies [2-4].
Methods and results
Our study consisted of six patients, four males and two females, age
range: 35-58 years, all suffering from severe scabies, of exotic origin,
presenting nodular manifestations and secondary eczematisation. Most of
the cases were initially misdiagnosed and therefore mistreated. None of
the patients had received any topical antiscabietic treatment in the previous
month. The diagnosis was made by scraping for microscopic evidence of
mites, their eggs or their fecal pellets. Written consent was obtained
from all patients after they has been informed about the nature and details
of the study.
Each patient received 200 µg/kg of ivermectin
(two tablets of 6 mg taken as single dose). The therapy was repeated after
one week in the more serious cases. Patients were allowed to use only
emollient local treatment, as necessary.
Patients were seen every week after the first dose of ivermectin.
The drug was extremely effective, especially regarding pruritus. Five
patients out of six reported a significant reduction in pruritus and a
return to a "good night's sleep" within 48 hours after treatment (the
sixth patient's clinical history will be presented separately, with photo-documentation,
showing the severity of the disease). Complete recovery occurred in four
weeks. In particular a gradual improvement of the nodular manifestations
was noticed during the follow-up visits. No side effects were seen in
any patient.
Case 6 was the most serious and requires a more
detailed presentation. C.G. is a 58-year-old male, who has been suffering
from a psychologically debilitating pruritus for three months, despite
undergoing systemic corticosteroid therapy for a total of 45 days (Fig.
1). He immediately underwent scraping for microscopic evidence
of mites. Then he was asked to take 200 µg/kg of ivermectin in a
single dose and to discontinue his current systemic corticosteroid therapy
immediately.
He mentioned a reduction in his pruritus during his first follow-up
interview, although he complained of worsening erythema, which was attributed
to the suspension of the antinflammatory corticosteroid therapy. The patient
was discharged with a prescription for emollient moisturizing cream, to
be used as necessary and emollient soaks. He required a second dose one
week after the first treatment. During the following weeks there was a
progressive reduction in eczematization and an improvement of the nodular
lesions. After 15 days of therapy the patient continued complaining about
his insomnia, even though his pruritus was greatly reduced. An antihistamine
and benzodiazepine were added for his problem. After four weeks, microscopic
search for mites and their products was negative, so the patient was considered
cured.
Discussion
Every year we observe a large number of new cases of scabies. Among
these were mistreated cases, atypical features, unusual localisation,
like the scalp, induced by prolonged corticosteroid therapy. The infestation
can mimic: contact dermatitis, dermatitis herpetiformis, seborrhoeic dermatitis,
drug induced eczema, bullous pemphigoid, etc. [5]. Often the diagnosis
is not easy. Current topical treatments are irritating when used in patients
with secondary eczematization and escoriations and are not effective in
persistent irritable nodules. Ivermectin, taken in a single dose, represents
an interesting choice with respect to local therapy, that has to be carefully
applied to all the skin below the neck. In our experience ivermectin has
been shown to be an effective treatment in scabies, especially regarding
pruritus, without any side effects. Moreover no local therapy was needed
in our patients, not even in those with nodular lesions.
The dose of ivermectin is 200 µg/kg taken in a single dose. The
patients should be seen weekly and supervised for a period of a month,
because the infestation could resolve within 4 weeks. In our study all
members of the household were treated with a local scabiecide in order
to avoid reinfestation. Disinfestation of clothing by high temperature
laundering was required for all the patients. We excluded from the therapy
elderly, children and subjects affected from any other illness because
they did not meet the inclusion criteria. We think that ivermectin is
an effective therapy even though further study is required to confirm
our data.
REFERENCES
1. Goa KL, McTavish D, Glissold SP. Ivermectin: a review of its antifilarial
activity, pharmacological properties and clinical efficacy in onchocerciasis.
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2. Traitement de la gale par ivermectine. La sélection bibliographique
du mois. Ann Dermatol Venereol 1996; 123: 697-700.
3. Meinking TL, Taplin D, Hermida JL, Pardo R, Kerdel FAFA. The treatment
of scabies with ivermectin. N Engl J Med 1995; 333: 26-30.
4. Glaziou P, Cartel JL, Alzieu P, Briotel C, et al. Comparison
of ivermectin and benzyl benzoate for treatment of scabies. Trop Med
Parasitol 1933; 44: 331-2.
5. Pauluzzi P, Scarpa C. Atypical features of scabietic infestation.
G Ital Dermatol Venereol 1995; 130: 307-10.
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