Scabies

Scabies presents as an intensely pruritic rash that predominantly involves hairless and thin skin such as web spaces of the hands and skin creases. Sensitization to mite products is responsible for the itch and therefore symptom onset is usually delayed by weeks in the first infection. Secondary bacterial infection with Staphylococcus aureus and Streptococcus pyogenes is responsible for significant morbidity. Crusted scabies, the most severe form of scabies, presents as a hyperkeratotic rash. Lesions are loaded with mites and such patients are highly infectious. Direct skin-to-skin contact is the most important mode of transmission. Parasitological diagnosis is difficult and therefore clinical diagnosis is usually relied upon, although new diagnostic methods are under development. The most commonly used treatment of choice is topical permethrin cream applied to the whole body. Ivermectin, administered orally, is increasingly being used, including for mass drug administration.