Initially, the flu may be shrugged off as just a common cold due to similar symptoms—such as a seem runny nose, sinus congestion, sneezing, and sore muscles and throat.
However, a prime differentiator between cold vs. flu is that similar symptoms will come on and worsen gradually with a cold, compared to a flu which hits suddenly and hard with the following symptoms…
The initial sign that you have the flu that you have the flu, and not just a routine cold, will be a high fever that soars between 102- and 106-degrees Fahrenheit (or 38-degrees Celsius). Typically, children’s fevers will be higher than adult fevers and can last 3 to 4 days before breaking.
2. Breathing Difficulty
Congestion and stubborn coughing will often cause chest tightness, constricted nasal passages, and as a result restricted breathing that can become labored. The flu can also make existing asthma or breathing issues worse.
Periodic cold chills caused by sweating (particularly night sweats) as your fever comes and goes is very common with a nasty flu as your body fights the illness and pushes it out of your body.
Headache, or more commonly, nasal and sinus pain, due to congestion is very typical with the flu, which will worsen before it gets better.
5. Achy Muscles
Aching muscles all over the body is very typical as the flu comes on. You’ll especially notice muscle tenderness in the back, arms, legs, and chest (if you have a stubborn cough).
Chest congestion that starts with a loose, hacking cough and develops into a persistent, dry cough is common with the flu. The persistent hacking can become severe and cause the throat and chest to be very tender.
7. Nasal Congestion
Sinus and nasal congestion is common with the flu and a common cold. However, with the flu, the chances of it developing into Bronchitis, pneumonia, or a sinus infection is much higher, and for young children and seniors, it can be life-threatening.
Weakness that drains and completely exhausts you is common with the flu. Compared to a regular cold, flu fatigue comes on rapidly and can last up to 2 or 3 weeks before your energy returns fully.
9. Sore Throat
One of the most common symptoms of the flu is a sore throat, which can be described as burning or scratchy (particularly in the back of the throat). It may cause glands to swell and swallowing to become difficult.
10. Pain and Sensitivity of the Eyes
Not only is it common for people with the flu to have aches and pains in their muscles, they may also experience such feelings in and around their eyes, particularly when they move them. In addition, Livestrong.com says other ocular symptoms of the flu can include “sensitivity to light,” known as photophobia, and a “burning sensation.”
While the source says that these symptoms tend to go away on their own, in cases where the eyes are “very red, produce discharge or get worse instead of better,” it is advised that the individual seek medical assessment.
11. Warm, Flushed and Sweaty Skin
As mentioned earlier, a common symptom of the flu is a high fever, which can cause the skin to be warm, flushed, and sweaty, especially on the face. This happens because, when your internal temperature reaches fever level (99.5-degrees Fahrenheit or 37.5-degree Celsius), the blood vessels close to the skin expand in order to help the body cool down.
Merck Manual indicates that you may also notice this redness in other areas, such as the mouth, throat, or even in the whites of the eyes, which can appear bloodshot and watery.
12. Gastrointestinal Problems
While gastrointestinal problems are typically more indicative of gastroenteritis (often referred to as the ‘stomach flu’), it is possible for them to occur with influenza as well. Healthline.com says, “Some strains of the virus can cause diarrhea, nausea, stomach pain, or vomiting.”
Although these symptoms more commonly occur in children, it is possible for adults with influenza to experience them as well. With vomiting, in particular, if it becomes acute, WebMD stresses that you should seek immediate medical assistance, as it may mean your illness is severe.
13. Loss of Appetite
Loss of appetite is another common symptoms of the flu, especially in those adults and children who experience gastrointestinal issues like nausea, vomiting, and diarrhea. With vomiting and diarrhea, in particular, frequent loss of fluids can lead to dehydration, which is a major health concern. Livestrong.com encourages increasing your liquid intake by “sipping on hot tea, soups and water.”
You can also help to calm unsettled digestion by “Eating a basic diet that consists of bland foods, such as toast, white rice, bananas, chicken and boiled potatoes,” adds the source. But if keeping any food down is a challenge, it is advised that you make an appointment with your doctor.
In some cases, the flu may be accompanied by dizziness, which Livestrong.com indicates is “most often related to dehydration.” The source goes on to explain that “Dizziness occurs with dehydration due to reduced water in the circulation, which can cause a drop in blood pressure — especially when rising to a sitting or standing position.”
But dizziness isn’t always because of dehydration. Sometimes it occurs as a side effect of over-the-counter medications that people take to relieve their flu symptoms—particularly those that have antihistamines in them. The source adds that flu complications like pneumonia and inner ear infections may also lead to dizziness.
As mentioned earlier, dehydration is a major concern associated with influenza. This is because it can lead to a variety of other symptoms including the dizziness just mentioned, as well as confusion. When experiencing confusion, it’s possible that you may not know what day it is or time it is, or be able to understand what others are saying.
Additionally, confusion “impedes the ability to listen to one’s body and respond accordingly,” says HealthPrep.com. As a result, it is considered by the Center for Disease Control and Prevention (along with dizziness) to be an emergency warning sign. Therefore, you should seek medical attention immediately if experiencing it.