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Disease&Treatment/Cornea&Ocular surfaces
Types of ocular hypersensitivity reactions, Gell & Coombs classification Immediate allergic autoimmune, cytotoxic, delayed reactions
eye_doc 2025. 4. 21. 23:44
👁 “Hypersensitivity Reactions in Ophthalmology – Types I to IV”
Hypersensitivity refers to inappropriate or exaggerated immune responses to antigens
that are typically tolerated by the body.
The Gell and Coombs classification (1963) remains the standard,
dividing reactions into four types (I–IV), each with distinct immunologic mechanisms and
clear links to various ocular diseases.
🧠 Hypersensitivity Types & Ophthalmic Conditions
TypeMechanismOcular Examples
| Type I (Immediate, IgE-mediated) | ||
| – Allergen binds to IgE on mast cells | ||
| → release of histamine, prostaglandins, etc. | ||
| – SAC | ||
| – VKC, AKC, GPC | ||
| Type II (Cytotoxic) | ||
| – Antibodies (IgG/IgM) target cell-bound antigens | ||
| → activate complement, cell lysis | ||
| – Mooren's ulcer | ||
| – Cicatricial pemphigoid | ||
| – Lens-induced uveitis | ||
| Type III (Immune complex-mediated) | ||
| – Antigen + antibody form immune complexes (IC) | ||
| → deposit in tissue → complement activation → inflammation | ||
| – Wessely ring | ||
| – SLE, RA, Wegener's granulomatosis | ||
| – Necrotizing scleritis | ||
| – Stevens-Johnson syndrome | ||
| Type IV (Delayed, T-cell mediated) | ||
| – CD4+ T cells: IFN-γ, IL-2 → macrophage activation | ||
| – CD8+ T cells: direct cytotoxicity | ||
| – Contact dermatitis | ||
| – Phlyctenulosis | ||
| – Disciform keratitis | ||
| – Corneal graft rejection | ||
| – SEI in EKC | ||
| – VKC, AKC, GPC (Mixed I+IV) |
✅ Clinical Insight
– Understanding the hypersensitivity type can guide treatment modality (e.g., antihistamines vs steroids vs immunosuppressants)
– Many ocular surface diseases are multifactorial (e.g., VKC = Type I + IV)