People who develop allergy symptoms sometimes can't tell them apart from common illnesses, such as a cold or flu. Even when symptoms relapse over time, patients don't always suspect allergic reactions, especially if they are susceptible to bacterial or viral infections. The severity and types of symptoms from hay fever and other allergy attacks may vary. Allergists are trained to recognize and identify the subtle signs of immune system diseases. Carefully tracking the degree and onset of flu-like symptoms will help doctors correctly diagnose allergies.
Headache
Headaches may give early warning of influenza conditions and arise more slowly in cases of hay fever and indoor allergies. In both viral illnesses and allergic reactions, however, a buildup of sinus pressure contributes to headache pain.
The University of Maryland Medical Center reports that chronic headaches may be a sign of indoor allergies. Unlike seasonal pollens, allergens such as pet dander, cockroaches, black mold and dust mites can affect patients at any time or all the time.
Respiratory Symptoms
Flu-like runny nose, stuffy nose and sneezing are also hallmarks of allergic reactions. When these conditions arise along with intense itching of the eyes, nose, mouth and throat, they may be allergy symptoms instead of a flu or cold.
According to the Mayo Clinic, the flu hits hard and fast, while a cold or allergies may build before expressing moderate to severe respiratory problems. Patients' systems may fluctuate between mucus drainage and buildup. Flu and hay fever respiratory symptoms should fade within a week. People with perennial allergies may experience continual low-level breathing problems.
Dry Cough
Inflammation of the throat accompanies hay fever, indoor allergies and flu conditions. Soreness and a dry, hacking cough may result. The UM Medical Center notes that postnasal drip from mucus accumulation may irritate the throat and trigger coughing. While these problems fade when allergen exposure ends, a dry cough can persist for weeks after a bout of the flu.
Diarrhea and Vomiting
Allergic reactions to pollen and indoor contaminants will not produce diarrhea and vomiting, but these flu-like reactions do occur in cases of food allergies. Digestive upset accompanies the flu virus for 2 to 4 days, the UM Medical Center relates. Diarrhea and vomiting allergy symptoms generally affect patients and then disappear on the same day that a problematic food was ingested.
Fatigue
The sudden, strong effects of the flu may produce feelings of fatigue and weakness, as the Mayo Clinic reports. High fever and loss of fluids from digestive problems can explain low energy. Allergy symptoms that include fatigue may be due to extended periods of breathing difficulty or the immune system's attempts to forcefully expel allergens by sneezing and coughing.
