Feature Article

Insect bites and skin infestations

Ian D Hamann



Insect bite reactions and skin infestations are common presentations to primary care physicians. However, accurate diagnosis and appropriate management of these problems is not always straightforward.

Key Points

  • The effect of an insect bite on an individual is caused by a variety of factors, acting singly or together. Most clinically significant reactions are due to the host’s immune response to the injection of allergens or toxins.
  • Mite attacks should always be considered when there is an unusual exposure, particularly to materials or foods that have been stored for long periods.
  • Not treating all the close physical contacts of a patient with scabies is a common reason for treatment failure.
  • Management of head lice can be problematic. Maldison may be effective, and there have been reports of success with ivermectin treatment. A newer approach is to use oral sulfamethoxazole–trimethoprim.
  • A variant of Barmah Forest virus has been described that causes an uncomfortable, rosacea-like facial rash lasting several days before becoming more typically morbilliform. Resolution is rapid, with few, if any, systemic symptoms.
  • All Australian doctors should be alert to the possibility of ‘exotic’ diseases because immigration and world travel have increased the likelihood of these presentations.