i have six lhasa apso. We do not want them to have this problem. #1 vet is the right choice. Our vet gave them Butler GentaSpray Topical Spray. We use Vet Kem to keep critters off and they were vaccinated for Lime Disease.
The vet also told us to shampoo them with Selsun Blue dandruff shampoo. They seem happy now. The Vet is the correct answer, but do ask about these products.