Allergens are things around us that can cause hypersensitive reactions to the immune system such as chemicals in the house, food, pollen, dust, bed mites, pet dander, mold, cigarette smoke, etc. 
Allergies can also be inherited from parents.  So, if both parents have allergies, the chances of a child developing allergies are usually greater than 80%.

Symptoms:
Sneezing, (post nasal drips), runny noise with clear nasal discharge, stuffy noise, itchy eyes, sinus headache, and loss of ability to smell are the most commons symptoms to Allergic Rhinitis.  With some variation, it’s common for patients to develop other types of allergy-related diseases such as asthma, eczema, dermatitis, and conjunctivitis.  In real life, about 20% to 30%of patients with allergies suffer from asthma.

Diagnosis:
Other than allergens, allergies can also be triggered by cold air or rapid changes in temperature, cigarette smoke, dust, and pollution.  In addition, when seasons change, these symptoms can worsen; so, it’s best to stay away from areas that are dusty, polluted, and crowded.

Allergies can develop at any age, but they commonly occur in children, elders, or some people with a weak immune system. Patients who have suffered a flu or cold for long durations have a greater chance of developing allergies, along with patients who have been exposed to these poor environmental conditions.