Avermectin exerts anti-inflammatory effect by downregulating the nuclear transcription factor kappa-B and mitogen-activated protein kinase activation pathway

Acute morbidity associated with scabies and other ectoparasitoses rapidly improves after treatment with ivermectin

In resource-poor settings, scabies is associated with considerable morbidity. Which factors determine morbidity and how rapidly it recedes after specific treatment is not known. Patients with scabies were recruited in three urban slums in Fortaleza, Northeast Brazil. Diagnosis was established according to dermatoscopy, skin scraping, or adhesive film test. Severity of scabies-associated morbidity was assessed semiquantitatively. Patients and close contacts were treated with oral ivermectin (200 μg/kg, repeated after 7 days) and followed up for 2 weeks. Ninety-five patients were included in the study. Papules were the most common lesion type (98.9%). Excoriations due to scratching were observed in 43.2% and bacterial superinfection in 24.2%. Predilection sites were the arms (82.1%) and the abdomen (81.1%). At baseline, 36.3% of patients complained about intense or severe itching. Intense or severe itch decreased to 6.3% 2 weeks after treatment (p=0.02). Whereas 37.5% of the patients complained about intense or severe itch-related sleep disturbances at baseline, only 8.8% reported the symptom 2 weeks after treatment (p=0.35). At baseline, the degree of itching was correlated with the degree of sleep disturbance (ρ=0.64; p<0.001). One week after the first dose of ivermectin, the intensity of itching and of sleep disturbance decreased significantly (p<0.001). In patients living in resource-poor setting, scabies was associated with considerable morbidity. Treatment with ivermectin rapidly reconstituted health in almost all cases.