Seasonal allergic conjunctivitis (SAC) | Perennial allergic conjunctivitis (PAC) | Atopic keratoconjunctivitis (AKC) | Atopic blepharoconjunctivitis (ABC) | Vernal keratoconjunctivitis (VKC) | Giant papillary conjunctivitis (GPC) | Contact dermatitis | |
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Prevalence | 25–50% of all AED | 0.03% of population | 1.5% of population | ? | 0.5% of all AED | Iatrogenic | Not known |
10–15% of population | Under 14 M > F Usually resolves by puberty After this M = F | ||||||
Severity | Mild | Mild | Sight threatening | Not sight threatening | Severe | Moderate | Moderate |
Range moderate to severe | Similar to AKC | ||||||
Signs | Small tarsal papillae | Similar less severe | Conjunctival scarring | Blepharitis | Florid — giant papilla in tarsus or limbus | Reaction to contact lens, stitches prosthesis | Skin, not cornea |
Papilla formation | Similar to AKC but no keratopathy | Conjunctival scarring | Florid giant papillae | Reaction to particular allergen | |||
PAC → Severe corneal opacification, vascularisation | Cataract and keratoconus association | Corneal PEE develop into ulcer with plaque | Skin erythema | ||||
Cataracts and keratoconus association | Sight threatening, Trantas’ spots (eosinophils) and gerontoxin | Oedema | |||||
Seasonal | Yes | All year round with seasonal variation | Sometimes | Sometimes | Yes | No | No |