When allergens enters the tear flim, it triggers the conjunctival mast cells that bear the IgE antibodies.
Calcium enters the cell
Degranulation of mast cells results in production of Histamine
Histamine release causes Vasodilatation and oedema and resulting reddishness and swelling of the eyes.
It is more common among the people who is already more prone to seasonal allergies. They develop it when they come into contact with a substance that triggers an allergic reaction in their eyes.
Giant papillary conjunctivitis:
It is a type of allergic conjunctivitis caused by the chronic presence of a foreign body in the eye. People who wear hard or rigid contact lenses, wear soft contact lenses that are not replaced frequently, have an exposed suture on the surface of the eye or have a prosthetic eye are more likely to develop this form of conjunctivitis.
Allergic conjunctivitis occurs more commonly among people who already have seasonal allergies. They develop it when they come into contact with a substance that triggers an allergic reaction in their eyes.
Giant papillary conjunctivitis is a type of allergic conjunctivitis caused by the chronic presence of a foreign body in the eye.
Bacterial conjunctivitis caused by staphylococcal or streptococcal bacteria from your own skin or respiratory system. Insects, physical contact with other people, poor hygiene (touching the eye with unclean hands), or using contaminated eye makeup and facial lotions can also cause the infection. Sharing makeup and wearing contact lenses that are not your own or are improperly cleaned can also cause bacterial conjunctivitis.
Viral conjunctivitis is most commonly caused by contagious viruses associated with the common cold. It can develop through exposure to the coughing or sneezing of someone with an upper respiratory tract infection. Viral conjunctivitis can also occur as the virus spreads along the body's own mucous membranes, which connect the lungs, throat, nose, tear ducts and conjunctiva. Since the tears drain into the nasal passageway, forceful nose blowing can cause a virus to move from your respiratory system to your eyes.
Ophthalmia neonatorum is a severe form of bacterial conjunctivitis that occurs in newborn babies. This is a serious condition that could lead to permanent eye damage if it is not treated immediately. Ophthalmia neonatorum occurs when an infant is exposed to chlamydia or gonorrhea while passing through the birth canal.
Chemical Conjunctivitis can be caused by irritants like air pollution, chlorine in swimming pools, and exposure to noxious chemicals.