These reactions are very seasonal, which could start to present themselves, depending on which latitude one is at, either in February or March and continue until May and is of course associated with the various blossoming trees, plants and shrubs.
Some of the symptoms are a runny nose, stuffy/ congested nose, coughing, sneezing, eye issues, asthma, skin rash and itching (as well as all sorts of symptoms which are associated with a person’s area of weakest immunity).
If symptoms have appeared in a child, the symptoms can then change over that person’s lifetime especially when they go through puberty. For example: stomach aches can later in their life develop into asthma, neurodermatitis or headaches. This is the reaction to the same substance, changing over different phases of their life.
If you don’t already have a vial for the specific type of pollen your client is reacting to, you can have them collect it by swabbing with a cotton ball, handkerchief or paper towel, etc. the dust off any horizontal railing, windowsill, etc., that is immediately outside their living space. Contained within this dust that has accumulated over several days/weeks there will be the information of the specific pollen that is in that area. Another way to collect this information is to leave a jar of water out for a couple of days. An inside-out loop of Scotch tape can also be stuck to the window.
Ideally a person should be treated for seasonal allergies prior to the start of the allergy season in their region. The pollen itself can also change (mutate) due to either radioactivity or smoke that is also in the air. In these cases, it is always best to take fresh samples each year.