For Hay Fever The "hay fever season" can be a different time of year for different people depending where in the world they live. In part, this is because trees, grasses, and weeds produce pollens during different seasons. In the last few years the weather in the United Kingdom has been much warmer than the long term average so the flowering times for many plants have altered. For example, Birch trees have flowered several weeks earlier in the last few years than they did several decades ago. Hay fever subsides with the onset of cold weather.

For example, people in the eastern and Midwestern United States who are sensitive to tree pollen may suffer in the early spring when trees such as elm, maple, birch and poplar are producing pollen. People who are sensitive to pollens produced by grasses may suffer in the late spring, and early summer, the time when most grasses are pollinating. About half of all hay fever sufferers are sensitive to grass pollens. Weeds flourish in most parts of the country from midsummer to late fall. In the late fall, ragweed is the most common problem. In fact, ragweed is the plant that causes the most hay fever. But an individual may react to one or more pollens in more than one of these groups, so the person´s "season" may be from early spring to the first frost. For that matter, people who are sensitive to dust, to dog or cat dander (tiny scales or particles that fall off hair, feathers, or skin) or to some other airborne material that they cannot protect themselves from may suffer all year round. Mould and fungus spores ("seeds"), also airborne during the summer and fall months, cause reactions in many people. Frequently found around hay, straw, and dead leaves, their growth is encouraged by humid weather and by places with poor air circulation--damp basements for instance. You can be sensitive to just one or two types of pollen, and so your pattern of symptoms may be different to someone else´s. The exact timing of symptoms can also vary slightly from year to year, depending on how the weather effects pollen production. Also the warmer conditions in the south produce pollen earlier than in the north, but the general pattern is the same each year. Town and cities have different pollen mixtures to the countryside, depending on what plants grow locally. Very high pollen counts can produce symptoms in some people who do not normally show hay fever symptoms, and so may only experience discomfort every few years.

Some people suffer all year round when they are allergic to things that are in the air all year. There are two common causes of this:

House dust mite is a minute insect living in most of our homes, and feeding on dust (which consists mainly of human skin cells). Its droppings easily get into the air, and we breathe them in. Insects you can not see are easy to ignore! Pet dust - in actual fact dead skin cells and hair particles from our beloved pets are dropping all around your house all the time. Other causes of symptoms can be food allergy, either to a food or to a flavouring or colouring, alcohol, smoke, stress, some medicines or many other triggers.