As a doctor their are several illnesses that happen suddenly, but in this what are sudden illnesses post i will tell you only four illenesses, kindly read this careerfully.

Sudden illnesses are medical conditions that develop quickly and unexpectedly. These types of illnesses can occur suddenly without any warning signs or symptoms. Examples of sudden illnesses include:

1) Heart attack.
2) Stroke.
3) Seizures.
4) Asthma attack.
5) Allergic reactions.

It's important to seek immediate medical attention if you experience any sudden illnesses or symptoms.