Introduction to Seasonal Allergies

What are Seasonal Allergies?

Seasonal allergies are allergic reactions which appear in certain periods of the year. The causes of seasonal allergies are aero-allergens, which are complex particles that are spread through the air. Aero-allergens include:

  1. Pollens
  2. Funghi
  3. Animal particles (e.g. fur)
  4. Dust
  5. Algae

These particles contain molecular components, usually proteins and glycoproteins, which induce the synthesis of IGE antibodies, thus making the patient sensible to such allergens. These can be taken in via inhalation (respiratory pathway), and upon repeated contact, the patient may exhibit allergic symptoms.

For a correct diagnosis, the physician attempts to draw connections between the circumstances in which the allergic condition appeared and the exposure to the allergen.

Pollens are of two categories:

  1. Entemophiles (spread via insects), these pollens are usually present in brightly colored and strong-smelling flowers. These pollens often cause allergies in flower-shop workers.
  2. Anemophiles (spread via air currents), responsible for most of the allergies affecting the respiratory tract.

A single cypress can release entire clouds of pollen, because they are light and easily transportable. This also depends on the climatic conditions. Aside from exposure, allergic conditions also depend on the allergen’s potency, or rather ability to cause allergies. The threshold value for triggering an allergic reaction due to pollens is 20-40 particles per cubic meter. The majority of pollen distributed over the first daylight hours, and reaches maximum concentration in the evening. Even a small breeze could cause the particles to travel for kilometers, thus distributing the allergen from rural to urban areas. In the morning the pollen particles lie on the ground and as the day progresses they elevate. Rain washes the particles away, which is why patients report alleviation in rainy periods. Pollen particles have such molecular composition that they can reach deep into the bronchi through inhalation. When they reach this site, they cause asthma symptoms. When they lodge into external points of entry into the organism they are responsible for symptoms such as a runny nose, conjunctivitis, or rashes.

The most productive pollen producing season begins in May and terminates in July. There is a pre-productive season lasts from February to April, and the post-productive season from August-October.

Fungi are also important allergens, which constitute the cause of around 5% of allergic conditions. They are most dangerous during the warmer seasons, they can be found domestically, especially in basements, storage houses, air conditioning units etc. One of the most common fungi is Aspergillum.

Animal particles could also act as allergens, for example particles from domestic animals such as dogs or cats, or animals such as horses, sheep, geese etc. The allergen may rest in the fur of animals, urine, etc. Allergies due to animals occur in specific conditions. Close prolonged contact is usually a prerequisite, from 6 months to 4 years.

Another allergen is household dust, which is a causative agent for 80% of allergic conditions. Dust is a mix of allergens which include vegetal, animal and mineral molecular components.

Industrial pollutants have become prominent in the industrialized modern world. These are mostly responsible for the so-called professional allergies. (Beer, cotton factories, animal breeding, flour factories, combustion plants, landfills, recycling factories, etc.)

One of the most prominent domestic pollutants is also cigarette smoke.

Doctor´s Advice

All patients suffering from seasonal allergies should not neglect their medicinal anti-histamine treatment, since if left untreated, their allergic conditions could progress to bronchial asthma. In the seasons when their allergies are most prominent, anti-histamines should be taken daily.

The most frequent seasonal allergies diseases are:

Medically Reviewed by a doctor on 22 Aug 2017
Medical Author: Dr. med. Diana Hysi