September 9th, 2010 | 
Author: Say that symptoms for a disease lets say… "cwncqncenc" disease (i made that up) and symptoms were… headache, stomach ache, ulceration, fatigue, and if the patient had 3/4 of those symptoms and lives out the rest of their life with that disease and without that ONE symptom… what cause them to be immune to that certain symptom?
Posted in 
Tags:
It’s not really "immunity" if you don’t get a particular symptom but still have the disease.
"Symptoms" are often subjective, like tiredness/fatigue. They are described by the patient themselves. Others (more correctly called "signs") are more objective, and might be noticed by a doctor (eg, yellow skin).
Some symptoms are very broad-ranging and could be a consequence of a large number of conditions. Three of your examples fall into this category – headache, stomach ache, and fatigue. Ulceration is more specific.
Whether or not these symptoms appear in a particular person might depend on a number of things, including their individual tolerance to pain/discomfort (eg, a mild headache in one person might not even be noticed in another), their overall health, and the relative severity of the disease itself (eg, a minor infection by a virus, or a major infection by the same virus).
So which symptoms appear can vary from person to person, and it’s possible that a person might never get one or more of the possible disease symptoms, even if they have the condition for life. There will however normally be one or more symptoms/signs that everybody gets all the time, and it is these ones which really define the disease.