Malaseb Medicated Shampoo for Dogs Cats PetsMalaseb Medicated Shampoo for Dogs Malaseb is registered to treat Seborrhoeic Dermatitis (Skin Infection involving bacteria and yeast) and Dermatophytosis (Ringworm Fungal Infection). How often should I apply Malaseb? In the case of seborrhoeic dermatitis, Malaseb should be used twice weekly when the infection is active. You may be able to reduce the frequency of bathing to once weekly or fortnightly once the infection is under control. In most