Seasonal Allergies

Overview of seasonal allergies

Allergies are very common in some countries where the seasonal variations are very prominent. For this very reason, these are also known as seasonal allergies. According to one statistics, rhinitis arising from seasonal allergies affects nearly 10-30% of the world population. Other global statistics show that the sensitization to the foreign proteins present in the environment affects nearly 40% of the world population. They also established that in the year 2012, 7.5% of the adult population were diagnosed with hay fever, which is a form of seasonal allergy. In school-going children and in the working professionals, seasonal allergies have been found to affect performance and productivity.

What are seasonal allergies?

Seasonal allergies are defined as the body’s immune response to certain environmental triggers which are more prevalent during a particular time of the year. In many countries it is popularly known as “allergic rhinitis” or “hay fever” and millions of people suffer from these diseases every year. Nasal swelling, irritation, and sneezing occur in a majority of the cases due to an acute inflammation of the nasal mucosa. The symptoms manifested are basically the inflammatory response of the body to the external triggers, also called “allergens”.

Seasonal allergies are very common in different regions in America. The statistics of the American Academy of Otolaryngic Allergy show that over 50 million Americans suffer from allergic rhinitis. The common trigger in most of those cases has been found to be pollen grains.

What are the main causes of seasonal allergies?

As implied by the name, seasonal allergies are primarily triggered by the seasonal variations and the environmental changes brought about by such variations. The main sources or triggers of seasonal allergies are listed below-

• Pollen grains spread by birds and bees
• Pollen particles spread by wind
• Certain varieties of improved pasture grasses (stronger allergens than Australian native grasses)
• Pollen generated from some exotic trees which are mainly planted for their pleasant Autumn colors
• Pellitory weed (also known as asthma weed) which mainly grows in Sydney
• Paterson’s curse (Echium plantagineum), commonly found in England
• Ragweed and Parthenium weed found in the United States

When a person comes in contact with something he is allergic to, his body produces the Immunoglobulin E (IgE) protein that reacts to the allergen and triggers the secretion of Leukotrienes, Histamine, Cytokines into the bloodstream. These chemicals, in turn, stimulate the body to secrete more IgE and the cycle continues unless intercepted by external medications. In Rhinorrhea, blood vessel obstruction occurs, along with the stimulation of the sensory nerves. Both result in the inflammation of the nasal passage and swelling.

How can you tell if someone has a seasonal allergy?

Seasonal allergies are easily identifiable if one has knowledge on the common signs and symptoms. The symptoms may range from mild to severe and usually occur at the same time each year. These are listed below-

• Constant itching in the nose, throat, eyes and the roof of the mouth
• Frequent sneezing
• Constant cough (usually non-productive)
• Runny nose and watery eyes
• Nasal congestion
• Formation of dark circles around the eyes
• Redness and tenderness of the eyes
• Tendency to rub and scratch the nose repeatedly
• Appearance of crease across the bridge of the nose
• Frequent throat clearing due to a grainy feeling inside the throat
• Mouth breathing, especially while sleeping (due to nasal congestion)
• Loss of olfactory sensation
• Recurrent nosebleeds (typically idiopathic in nature)
• Frequent ear infections that often result in hearing loss
• Cold and flu-like symptoms that continue for over 10 days
• Infections of the sinus
• Chronic fatigue and general body weakness

What are the main types of seasonal allergies?

Based on the time of the year, seasonal allergies can be classified into the following types –

• Early Spring Allergy: The most common allergen at the beginning of Spring, particularly in America is pollen grains acquired from the trees. The other common outdoor allergens at this time of the year are generated from the trees like- Beech, Cedar, Birch, Hickory, Maple, Sycamore, Poplar, and Ash.
• Late Spring / Early summer allergy: The allergies caused at this time of the year are mainly due to the pollen grains from the 1200 different species of grass that grow in North America every year. The main varieties of grasses that are responsible for allergies during this time of the year are- Kentucky Bluegrass, Sweet Vernal, Orchard, Timothy grass, Bermuda, Johnson.
• Weed Pollen allergy: These allergies are more common in the later part of summer and fall. The primary allergen, in this case, is the Ragweed pollen. Some of the other pollen producing weeds that act as allergens are- Pigweeds, Lambs Quarters, Curly dock, Sheep sorrel, plantain, and sagebrush.

Recommendations for seasonal allergies

Here are some of the dos and don’ts for minimizing seasonal allergies-

• Stay indoors on the days with high pollen count (windy days)
• Keep the windows of your home and cars closed
• Take a shower every time you come home (helps shed off the pollen grains)
• Wear a mask while mowing the grass
• Do not indulge in picnics or other outdoor activities during the pollen seasons

Diagnosis, treatment, & prevention

Effective diagnosis of seasonal allergies can be carried out by studying the history of infections and carrying out some necessary tests like swab test and sputum test. This helps eliminate the diseases with similar symptoms of cold and flu, pneumonia or viral fever.

The treatment mainly depends on the type and severity of the allergy.

• Nasal sprays– nasal sprays are available both over-the-counter and prescription. They help mainly in relieving sinus-related symptoms. There are several types of sprays based on the type of allergy and their clinical manifestations. Some of the sprays are steroid sprays, antihistamine sprays, decongestant sprays, saline nasal sprays etc.
• Allergy drugs- These drugs can diminish the severity of the body’s reaction towards allergens. Some of them are antihistamines, mast cell stabilizers, decongestants, steroids, and leukotriene modifiers. Epinephrine is the drug of choice in case of anaphylaxis.
• Anti-Immunoglobulin E (IgE) Therapy-It reduces the number of IgE (immunoglobulin E) antibodies produced by the immune system in response to the allergens thereby decreasing the allergic responses.
• Immunotherapy- Allergy shots and allergy drops can be used for protection against allergens by developing resistance. Allergy shots involve the injection of allergen extracts in a very small quantity. Allergy drops involve the administration of small amounts of allergen sublingually (beneath the tongue) in the form of liquid or tablets.

Prevention of allergies is mainly by reduction of exposure to the allergens. Maintaining hygiene such as washing hands, bed linens, curtains, carpets etc. is important to get rid of allergens. Use of shots and nasal sprays prior to the beginning of the allergic season can help in reducing allergy episodes.

References