Allergic conjunctivitis Allergic conjunctivitis Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), edema (swelling) of the conjunctiva, itching, and increased lacrimation (production of tears). If this is combined with rhinitis, the condition is termed allergic rhinoconjunctivitis. The symptoms are due to release of histamine and other active substances by mast cells, which stimulate dilation of blood vessels, irritate nerve endings, and increase secretion of tears.
Rhinitis asthma developing later in life. Environmental irritants acts as modulators of airway inflammation in these contiguous airways. Development of occupational asthma is often preceded by occupational rhinitis. Among the causative agents are flours, enzymes used in processing food, latex, isocyanates, welding fumes, epoxy resins, and formaldehyde. Accordingly, prognosis of occupational asthma is contingent on early diagnosis and the adoption of protective measures for rhinitis. In the case of infectious rhinitis, vaccination against influenza viruses, adenoviruses, measles, rubella, "Streptococcus pneumoniae", "Haemophilus influenzae", diphtheria, "Bacillus anthracis", and "Bordetella pertussis" may help prevent it. The management of rhinitis depends on the underlying cause.