Why Cats Sneeze

Check out this answer from Consensus:

Sneezing in cats is a multifaceted reflex that can be triggered by infections, allergies, and neural mechanisms. Understanding the underlying causes and mechanisms is essential for effective diagnosis and treatment. Veterinarians and pet owners should be aware of the potential health risks associated with sneezing, especially in cases of infectious diseases like sporotrichosis, to prevent transmission and ensure proper care.

Sneezing in cats is a common reflex that serves as a protective mechanism for the respiratory tract. It can be triggered by various factors, including infections, irritants, and underlying health conditions. Understanding the causes and mechanisms of sneezing in cats is crucial for veterinarians and pet owners to ensure proper diagnosis and treatment.

Causes of Sneezing in Cats

Infections

One of the primary causes of sneezing in cats is respiratory infections. These can be viral, bacterial, or fungal in nature. For instance, chronic nasal discharge and sneezing are often associated with respiratory virus infections, which can lead to long-term issues such as squamous metaplasia of the nasal mucosa, making complete resolution unlikely2. Additionally, fungal infections like cat-transmitted sporotrichosis (CTS) caused by Sporothrix brasiliensis can also lead to sneezing. This infection can be transmitted through respiratory droplets expelled during sneezing, posing a risk to humans and other animals1.

Allergies and Irritants

Allergic reactions to environmental factors such as pollen, dust, or chemicals can also cause sneezing in cats. These allergens can irritate the nasal passages, leading to frequent sneezing as the body attempts to expel the irritants.

Neurological Pathways

The sneeze reflex in cats involves complex neural circuits. The trigeminal nerve plays a significant role in triggering sneezing. Electrical stimulation of different branches of the trigeminal nerve, such as the anterior ethmoidal, posterior nasal, and infraorbital nerves, can induce sneezing5. Moreover, a peptidergic pathway involving neuromedin B (NMB) has been identified as essential for signaling sneezing. NMB-sensitive neurons in the brainstem project to the caudal ventral respiratory group (cVRG), which is involved in the sneezing reflex6.

Mechanisms of Sneezing

Motor Patterns

Sneezing and coughing share similar respiratory and laryngeal motor patterns, including an inspiration phase, compression phase, and expulsion phase. However, the main difference lies in the activity of the styloglossus (SG) muscle, which is explosively activated during the expulsion phase of sneezing, leading to greater nasal airflow compared to coughing3.

Neural Activity

The sneeze reflex involves significant changes in the activity of respiratory-related neurons in the medulla and brainstem. For example, stimulation of the ethmoidal nerve can lead to the inhibition of inspiratory neurons and activation of expiratory neurons, resulting in the sneeze reflex7 8. Additionally, c-Fos-like immunoreactivity studies have shown that sneezing activates specific areas in the brainstem, including the solitary complex and the nucleus retroambiguus, which are involved in respiratory control4.