Sounds like it could be a yeast, bacterial or combined infection or an underlying allergy causing the skin to become infected.

Speak with the vet about using a medicated shampoo such as Malaseb® or Malaseb® Lite to treat the infection and also Barazone® which is formulated for the symptomatic treatment of certain allergic conditions.

Dermcare Barazone® Leave-on Conditioner is only available under veterinary authorisation. Registered pursuant to the ACVM Act 1997, No. A011938. Dermcare Malaseb® Medicated Shampoo is registered pursuant to the ACVM Act 1997, No. A7641. See www.foodsafety.govt.nz for registration conditions.