An aching head, sore muscles, runny nose, as well as lack of energy and an upset stomach are all flu symptoms; however, they can also indicate a food allergy or allergic rhinitis, which can be seasonal or year-round, notes MayoClinic.com.

The major signs of a surgical site infection are pain, fever and changes in the appearance of the incision and surrounding skin. Infection after surgery can lead to more pain, prolonged time in the hospital, readmission to the hospital and, in rare cases, life-threatening illness.

In the early stages, it is difficult to tell the difference between the papules of chickenpox and the bites of a flea. Chickenpox is an airborne illness often associated with childhood. It presents with a hive-like rash that over time turns into a series of blisters.

The 24-hour flu or stomach flu are common terms that refers to an illness with short-lived gastrointestinal symptoms such as nausea, diarrhea and vomiting. More accurately termed gastroenteritis, this illness is typically caused by a virus, and sometimes is transmitted through food or water.

Flu shots contain deactivated, or killed, flu viruses. For the 2010-2011 flu season, the U.S. Centers for Disease Control and Prevention, or CDC, recommends that everyone over the age of 6 months be vaccinated against the flu.

The influenza virus, or the flu, is an infection that attacks the respiratory tract. According to the Mayo Clinic, the most common symptoms of this illness are fever, chills, headache, cough, body aches, fatigue, nasal congestion and loss of appetite.

Chickenpox is a highly contagious disease for people who have not been vaccinated. It is caused by the varicella virus and generally strikes children younger than 15. According to the Mayo Clinic, the signs and symptoms of chicken pox arrive in three phases. At the onset, raised red or pink bumps appear on the skin.

A flutter or cough sensation in the chest is medically referred to as an atrial fibrillation, which is a type of heart rhythm disorder known as an arrhythmia.

Candida parapsilosis is an yeast that belongs to the Candida family. It is commonly associated with blood, wound and tissue infections in individuals with reduced immunity, such as hospitalized patients and premature infants. In fact, according to a March 2002 study published in "Diagnostic Microbiology and Disease,"

A dry tickling cough causes unwanted irritation throughout the day. A persistent cough interrupts school, work and even a good night’s rest, and may be associated with sinusitis, asthma, bronchitis or other underlying conditions. A variety of home remedies and over-the-counter medications bring relief to your cough.

Antibiotics are chemicals that have the ability to inhibit the growth of microorganisms, especially bacteria, and are either produced naturally by other microorganisms or synthetically in a laboratory.

Nasal congestion is a common ailment that occurs in response to viruses, such as the cold and flu, allergies, sinus infections and other problems. Cleaning out your nose can improve your breathing, help you sleep and reduce your discomfort.