Pelodera Dermatitis (Damp Hay Itch) in dogs

This disease is caused by the larvae of a threadlike worm found in decaying rice hulls, straw, marsh hay, and other grasses that are in contact with damp soil. The larvae burrow into the skin of the dog’s chest, abdomen, and feet, causing intense itching and pimplelike bumps. Later, you may see raw, crusted, inflamed areas where the dog has scratched and chewed the skin.

The condition is found in dogs who are bedded on damp hay and straw. The diagnosis is made by finding the worm larvae on microscopic examination of skin scrapings.

Treatment: Bathe the dog with a benzoyl peroxide shampoo such as OxyDex or Pyoben to remove scales and crusts. Follow with an organophosphate insecticide dip such as Paramite (see Using Insecticides). Repeat the dip in one week if the dog continues to itch. Apply topical antibiotic ointment to inflamed skin areas three times a day.

Clean out old hay and straw. Wash the dog’s bedding and spray the sleeping area with an organophosphate insecticide containing malathion or diazinon. Change the bedding from hay to cedar shavings or shredded paper, or provide the dog with a fabric-covered sleeping pad that is washed frequently.