Onset of ME/CFS

The onset of ME/CFS can be sudden or gradual. There is debate as to whether sudden or gradual onset is more common, and even whether those with gradual onset can be considered to have 'true' ME. In cases of sudden onset, it is usually easy to identify the trigger of the illness, such as trauma or a viral infection.

Criteria

 * In the Holmes criteria, description of the main symptom complex as initially developing over a few hours to a few days is an optional criteria for diagnosis, under the section Minor Symptom Criteria.