MODEL RELEASED. Hay fever mask. Woman hay fever sufferer sniffing a flower through a mask. Hay fever, or allergic rhinitis, is caused by an allergic reaction to tiny airborne particles such as flower pollen. This reaction causes an inflammation of the lining of the nose and can result in sneezing, nasal congestion and watery eyes. Although the condition can be treated with decongestant or corticosteroid drugs, the best course of action for sufferers is to avoid the particles which cause the condition.