Allergic rhinitis is triggered by the presence of allergens. Grass pollen is the commonest cause of allergic rhinitis in Britain. During the months of May, June, and July, the level of grass pollen becomes high enough to cause symptoms of seasonal allergic rhinitis, or hayfever, in susceptible people. Allergens are typically soluble low molecular weight proteins, frequently with enzymatic activity, which trigger an immune response with a low dose. Symptoms and signs of allergic rhinitis in TCM include as follows:

1. Syndrome of wind and cold invading the lung
Main symptoms and signs: Short duration of onset, paroxysmal nasal itch and sneezing, clear and thin nasal discharge, nasal obstruction, or with cough, expectoration of sputum with whitish colour and aversion to wind, whitish nasal mucosa with edema, reddish tongue with whitish thin fur, floating and tense pulse.

2. Syndrome of internal accumulation of heat in the lung
Main symptoms and signs: Repeated onset of nasal itch, sneezing, clear nasal discharge with scanty amount, nasal obstruction, dryness of the nasal cavity during the intermittent stage, thirst with inclination to drink, reddish complexion, reddish nasal mucosa with swelling, reddish tongue with whitish or yellowish fur as well as rapid pulse.

3. Syndrome of qi deficiency of the lung and spleen
Main symptoms and signs: Long duration of attack, repeated onset of nasal itch and sneezing, clear and profuse nasal discharge and nasal obstruction which occur or worsen after fatigue, or cough, expectoration, anorexia, loose stool, fatigue of limbs, pale nasal mucosa with severer edema, reddish tongue with whitish and thin or whitish and greasy fur, thready and weak pulse.

4. Syndrome of yang deficiency of the kidney
Main symptoms and signs: Long duration of onset, paroxysmal nasal itch and sneezing, clear nasal discharge, nasal obstruction, anosmia, aversion to cold, cold limbs, loose stool, frequent and profuse nocturnal urine, pale or bluish-greyish nasal mucosa, enlargement of conchae, pale tongue with whitish fur, deep and thready pulse.