a6e96f85__Infections____Their_Treatment__Allergies
[Symptom] Sudden Symptoms [Cold] Cold symptoms tend to develop over a few days. [Flu] The flu has a rapid onset within 3-6 hours. The flu hits hard and includes sudden symptoms like high fever, aches and pains. [Allergies] 
Rapid onset.
Flu versus Cold (Upper Respiratory Infections) & Their Treatment
Allergies