Thanks for posting your query.
Do you have recurrent watery diarrhea, abdominal pain
and bleeding per rectum?
There may be possibility of viral induced upper respiratory tract
infection with mouth ulcers.
presence of cold, cough along with mouth ulcers suggest the diagnosis.
You should consult with internal medicine specialist and should go for thorough check up.
You and your sister should take multivitamin
with zinc supplements, vitamin C, rebapimide and proton pump inhibitors.
You should also take cough suppressants along complete antibiotic course.
You should also go for colonoscopy
if above mentioned symptoms are also present.
Dr. Mayank Bhargava