DEFINITION
- It is the inflammation of conjunctiva due to allergic or hypersensitivity reactions which may be immediate (humoral) or delayed (cellular).
ETIOLOGY
- Allergic conjunctivitis, is a type-I immediate hypersensitivity reaction mediated by IgE and subsequent mast cell activation, following exposure of ocular surface to airborne allergens. Family history of atopy might be present.
- Simple allergic conjunctivitis is known to occur in two forms:
- SEASONAL ALLERGIC CONJUNCTIVITIS (SAC)
- SAC is a response to seasonal allergens such as tree and grass pollens.
- PERENNIAL ALLERGIC CONJUNCTIVITIS (PAC)
- PACis a response to perennial allergens such as house dust, animal dander and mite. It is not so common.
PATHOLOGY
- Vascular Response
- Characterised by sudden and extreme vasodilation and increased permeability of vessels leading to exudation.
- Cellular Response
- In the form of conjunctival infiltration and exudation in the discharge of eosinophils, plasma cells and mast cells producing histamine and histamine-like substances.
- Conjunctival Response
- In the form of boggy swelling of conjunctiva followed by increased connective tissue formation and mild papillary hyperplasia.
CLINICAL FEATURES
| SYMPTOMS | SIGNS |
| Intense itching and burning sensation in the eyesWatery mucus, stringy dischargeMild photophobia | Hyperaemia & chemosis which give a swollen juicy appearance to the conjunctivaMild papillary reaction may be seen on palpebral conjunctiva.Oedema of lids is often present. |
TREATMENT
- Elimination of allergens if possible.
- Topical vasoconstrictors
- Naphazoline
- Antizoline
- Tetrahydrozoline.
- Artificial tears like carboxymethyl cellulose provide soothing effect.
- Mast cell stabilizers
- Sodium Cromoglycate
- Nedocromil Sodium
- Dual action antihistamines and mast cell stabilizers
- Azilastine
- Olopatidine
- Ketotifen
- Steroid eyedrops should be avoided.
- Systemic antihistaminic drugs are useful in acute cases with marked itching.
- Desensitization has been tried without much rewarding results.
PHLYCTENULAR KERATOCONJUNCTIVITIS
DEFINITION
- Phlyctenular keratoconjunctivitis is a characteristic nodular affection occurring as an allergic response of the conjunctival and corneal epithelium to some endogenous allergens to which they have become sensitized.
ETIOLOGY
- It is believed to be a delayed hypersensitivity (Type IV-cell mediated) response to endogenous microbial proteins so called as microbial allergic conjunctivitis.
CAUSATIVE ALLERGENS
- Tuberculous proteins
- Staphylococcus proteins
PREDISPOSING FACTORS
- Age : Peak age group is 3–15 years.
- Sex : Incidence is higher in girls than boys.
- Undernourishment
- Living Conditions: Overcrowded and unhygienic.
- Season. It occurs in all climates but incidence is high in spring and summer seasons.
PATHOLOGY
- STAGE OF NODULE FORMATION.
- In this stage, there occurs exudation and infiltration of leucocytes into the deeper layers of conjunctiva leading to a nodule formation.
- The neighbouring blood vessels dilate and their endothelium proliferates.
- STAGE OF ULCERATION
- Later on necrosis occurs at the apex of the nodule and an ulcer is formed.
- Leucocytic infiltration increases with plasma cells and mast cells.
- STAGE OF GRANULATION
- Eventually, floor of the ulcer becomes covered by granulation tissue.
- STAGE OF HEALING
- Healing occurs usually with minimal scarring.
CLINICAL FEATURES
SYMPTOMS
- Mild discomfort in the eye
- Irritation
- Reflex watering.
SIGNS
- The phlyctenular conjunctivitis can present in three forms: Simple, Necrotizing & Miliary.
- SIMPLE PHYLCTENULAR CONJUNCTIVITIS
- It is the most commonly seen variety.
- It is characterised by the presence of a typical pinkish white nodule surrounded by hyperaemia on the bulbar conjunctiva, usually near the limbus.
- Most of the times there is solitary nodule but at times there may be two nodules .
- In a few days the nodule ulcerates at apex which later on gets epithelised. Rest of the conjunctiva is normal.
- NECROTIZING PHLYCTENULAR CONJUNCTIVITIS
- It is characterised by the presence of a very large phlycten with necrosis and ulceration leading to a severe pustular conjunctivitis.
- MILIARY PHLYCTENULAR CONJUNCTIVITIS
- It is characterised by the presence of multiple phlyctens which may be arranged haphazardly or in the form of a ring around the limbus and may even form a ring ulcer.
CLINICAL COURSE
- It is usually self-limiting and phlycten disappears in 8–10 days leaving no trace. However, recurrences are very common.
DIFFERENTIAL DIAGNOSIS
- Episcleritis
- Scleritis
- Conjunctival foreign body granuloma.
- Presence of one or more whitish raised nodules on the bulbar conjunctiva near the limbus, with hyperaemia usually of the surrounding conjunctiva, in a child living in bad hygienic conditions (most of the times) are the diagnostic features of the phlyctenular conjunctivitis.
MANAGEMENT
- LOCAL THERAPY
- Topical steroids, in the form of eye drops or ointment (dexamethasone or betamethasone)
- Antibiotic drops and ointment should be added to take care of the associated secondary infection.
- Atropine (1%) eye ointment should be applied once daily when cornea is involved.
- SPECIFIC THERAPY
- Attempts must be made to search and eradicate the following causative conditions:
- Tuberculous infection should be excluded by X-rays chest, Mantoux test, TLC, DLC and ESR. In case, a tubercular focus is discovered, antitubercular treatment should be started to combat the infection.
- Septic focus, in the form of tonsillitis, adenoiditis, or caries teeth, when present should be adequately treated by systemic antibiotics and necessary surgical measures.
- Parasitic infestation should be ruled out by repeated stool examination and when discovered should be adequately treated for complete eradication.
- GENERAL MEASURES
- Aimed to improve the health of child are equally important.
- Attempts should be made to provide high protein diet supplemented with vitamins A, C and D.
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