The frontal and maxillary sinuses are extensions of the nasal cavity and are
lined by a mucous membrane similar to the one that lines the nose. Accordingly,
infections in the nasal cavity may spread to the sinuses, and vice versa. A
nasal infection is called rhinitis and a sinus infection is called sinusitis.
The signs of rhinitis and sinusitis are sneezing, nasal
gagging or retching from a postnasal drip. The discharge is thick, creamy,
and foul smelling.
The itchy skin diseases in this table are characterized by
constant scratching, biting at the skin, and rubbing up against objects to
relieve the itch.
Allergic contact dermatitis: Same as contact
dermatitis, but rash may spread beyond the area of contact. Requires
repeated or continuous exposure to allergen (such as wearing a flea
atopy: Severe itching that occurs in young dogs and begins in late
summer and fall. Caused by seasonal pollens. Occurs in mixed breeds...
In young dogs, bacterial rhinitis and
sinusitis usually do not occur unless the mucous membrane has been damaged by
an upper respiratory infection, foreign body in the nasal cavity, or trauma to
the nose. Respiratory infections caused by the herpesvirus, adenovirus, or parainfluenza
virus are the most common causes of acute rhinitis. These infections may be
followed by secondary bacterial involvement.
Canine distemper is a serious cause of secondary bacterial rhinitis. The
discharge is mucoid and purulent. Other signs of distemper will be present.
In older dogs, tumors and infected teeth are the most common
causes of rhinitis and sinusitis. Both are characterized by a chronic,
long-standing purulent discharge from one nostril, along with sneezing and
sniffling. Tumors and abscessed teeth may cause a blood-streaked discharge.
The diagnosis of rhinitis or sinusitis is based on X-rays, cultures, direct
visualization of the nasal cavity using a flexible endoscope, and, in some
cases, tissue biopsy.
Treatment: Bacterial rhinitis following upper respiratory infection is
treated with broad-spectrum antibiotics
that are continued for at least two weeks. Fungal infections usually respond to
one of the newer antifungal agents, such as itraconazole or fluconazole.
Antifungal drugs are given for six to eight weeks.
WebMD Veterinary Reference from "Dog Owner's Home Veterinary Handbook"