Allergy is a common overreaction of our immune system in response to harmless substances. When someone with an allergy comes in contact with an allergen, their immune system slowly builds sensitivity to it before it begins to overreact. However, as it becomes sensitive to the allergen, it begins creating antibodies that attack it, and this process is called sensitization. However, sensitization can take time.

The most common types of allergies are:

• Weeds: Late summer and early fall is the time for weed allergies. Most people are allergic to 17 species of ragweed found in almost every region across the country.
• Dust mites: These small, eight-legged creatures belong to the same family as spiders and ticks. They multiply quickly in warm and humid places and are found everywhere around the house — from beddings to carpets and more.
• Grass: Grass causes the symptoms of an allergy after trees complete pollinating, which can last from late spring to the early summer. Varieties like sweet vernal, timothy grass, and red top are the most common allergens.
• Mold: These microscopic plants reproduce by sending spores into the air, and people may develop an allergy to these spores. Mold thrives in warm, moist, and dark areas.
• Pollen: Pollen is the male reproductive part of a plant, and it is dust-like to touch. Some trees begin producing pollen from January. Large trees like oak produce loads of pollen, and evergreen trees like cypress, cedar, and juniper also produce pollen. Moreover, if you are allergic to the pollen of one tree, there’s a high probability that you will be allergic to all of them.
• Asthma: Asthma is caused due to inflammation and swelling in the airways of the lungs. People who have asthma face this inflammation constantly, and a lot of times, they may find it hard to breathe because of the inflammation. Their airways are also over-sensitive and react to substances which don’t bother others.
• Atopic eczema: Eczema is an itchy skin rash which leads to the formation of little pink bumps that may join together to form a pattern of red patches. Atopic eczema is also known as childhood eczema. Dermatitis is the name used when the reaction is caused due to an external agent.
• Medication allergy: Although prescription medicines go through rigorous testing, some individuals still develop side effects due to their use. However, most medications only lead to minor side effects due to which you can continue using them. However, some may lead to the appearance of severe symptoms.
• Food allergy: Food hypersensitivity which involves the immune system is called food allergy.
• Rhinitis: It is the term used to describe inflammation in the lining of the nose and leads to symptoms like a runny nose, sneezing, itching, nasal blockage, and more. The allergy can be seasonal, or it can last all year around. Some common causes include cats, dust mites, dogs, and the presence of other pets.
  In most cases, it is easy to treat allergies, but in severe cases, one must seek immediate medical attention.