Allergic conjunctivitis Causes Symptoms Treatment Allergic Conjunctivitis
Allergic conjunctivitis is defined as the inflammation of the membrane covering the white part of the eyes or conjunctiva due to allergy. Although allergens that act on different people may differ. The common cause of allergic conjunctivitis is hay fever.
Frequency of Allergic conjunctivitis
Allergic conjunctivitis occurs very frequently and is seen most commonly in areas there rare seasonal allergens.
Mortality/Morbidity with Allergic conjunctivitis
Allergic conjunctivitis can cause visual loss rarely.
Race gets affected with Allergic conjunctivitis
VKC occurs predominantly in areas with tropical and temperate climates, such as the Mediterranean, the Middle East, and Africa.
The limbal form of VKC commonly occurs in dark-skinned individuals from Africa and India.
Age and Allergic conjunctivitis
VKC mainly affects young males with onset generally in the first decade and with dates up to one decade. Its symptoms usually rise up at the onset of puberty and then subside.
Signs and symptoms of Allergic conjunctivitis
Symptoms of allergic conjunctivitis include redness of eyes which is mainly due to vasodilatation of the peripheral small blood vessels, edema on the conjunctiva, increased lacrimation and itching. If all these symptoms combine with rhinitis, then it is termed allergic rhinoconjunctivitis.
The conjunctiva is a thin membrane that covers the eye. When an allergen irritates the conjunctiva, common symptoms that occur in the eye include:
Occular itching, eye lid swelling, , photophobia, watery discharge, tearing and foreign body sensation.
Itching is the most typical symptom of allergic conjunctivitis and more than 75% of patients report this symptom when they consult a doctor for treatment.
When the weather is warm and dry, the symptoms become more worsen
Types of allergic conjunctivitis
Allergic conjunctivitis is divided into five.
- Seasonal allergic conjunctivitis (SAC)
- Perennial allergic conjunctivitis (PAC)
- Vernal keratoconjunctivitis (VKC),
- Atopic keratoconjunctivitis (AKC),
- Giant papillary conjunctivitis (GPC)
SAC and PAC
Both the Seasonal Allergic Conjunctivitis (SAC) and Perennial Allergic Conjunctivitis (PAC) are classified as acute allergic conjunctival disorders. SAC is the most commonly found occular allergy. Symptoms include itching and reddish eyes.
VKC and AKC
Both the Vernal Keratoconjunctivitis (VKC) and Atopic Keratoconjunctivitis (AKC) are considered as chronic allergic diseases in which conjunctival fibroblasts, epithelial cells, eosinophils, mast cells, aggravate the histology of the conjunctiva.
GPC
Giant Papillary Conjunctivitis (GPC) is truly not an occular allergic reaction and is caused by repeated irritation of the conjunctiva mechanically. Repeated contact with the conjunctival surface caused by the use of contact lenses is associated with GPC.
Diagnosis of Allergic Conjunctivitis
Lab Studies
In case of seasonal and perennial allergic conjunctivitis
Superficial conjunctival scrapings will help in establishing the diagnosis by reveal of eosinophils, but can be done only in most severe cases, since eosinophils are found in the deeper layers of the substantia propria of the conjunctiva.
Various inflammatory mediators, like IgE, tryptase andhistamine, as allergic activity indicators.
Skin testing by an allergist may provide definitive diagnosis
vernal keratoconjunctivitis: Conjunctival scrapings done to the superior tarsal conjunctiva show an abundance of eosinophils.
Histologic Findings
Vernal keratoconjunctivitis
Conjunctival biopsy shows that there are a large number of mast cells in the substantia propria. Histochemical analysis of mast cells present in VKC shows neutral proteases tryptase and chymase. There is active proliferation of fibroblast, which leads to deposition of collagen fibers in the substantia propria which results in conjunctival thickening.
Atopic keratoconjunctivitis
Eosinophils may be present, when patients with AKC is done with Conjunctival scrapings, although the number of cells is not as significant as that seen in VKC. Free eosinophilic granules, which are seen in VKC, are not seen in AKC. Mast cells also are also found within the substantia propria.
Giant papillary conjunctivitis
Histologic findings in GPC includes cellular infiltration of the conjunctiva, with the number of cell types. Plasma cells, mast cells, eosinophils, lymphocytes, and basophils have been identified within the substantia propria
Treatment of Allergic Conjunctivitis
- Medical Care
In case of seasonal and perennial allergic conjunctivitis
Topical antihistamines are available, including epinastine and azelastine. - Vasoconstrictors include naphazoline, phenylephrine, oxymetazoline, and tetrahydrozoline
- Mast cell stabilizers include cromolyn sodium and lodoxamide Olopatadine, nedocromil, and ketotifen .
- Nonsteroidal anti-inflammatory drugs: ketorolac tromethamine
- Surgical Care
Vernal keratoconjunctivitis
Cases of corneal shield ulcer may require superficial keratectomy to promote regeneration epithelium.
Other surgical procedures, such as cryoablation of giant papillae
Atopic keratoconjunctivitis: Keratoplasty