Can cat allergies cause an asthma attack?

Yes: Cat allergy seems to be particularly potent for triggering asthma symptoms in patients with cat allergy + asthma.

Yes...: Exposure to cats in an allergic patient can result in bronchospasm resulting in an asthma exacerbation. In a patient without an asthma history, this can be their first episode of bronchospasm. Once the bronchospasm recurs, a diagnosis of asthma is made. The best prevention is to avoid the cat if possible.