Allergic Conjunctivitis (Treatment, causes)

The translucent membrane that lines the eyelid and eyeball known as conjunctiva becomes inflamed, resulting in conjunctivitis. Conjunctival tiny blood vessels are more obvious when they are inflamed and swollen. The white area of the eyes seems reddish or pink because of this thus Conjunctivitis is also known as pink eye.

Viral infections are most frequently to blame for conjunctivitis. Additionally, it might be brought on by a bacterial infection, an allergic reaction, or in infants, a partially opened tear duct.

Even while the conjunctiva can cause pain, it rarely impairs eyesight. Pink eye irritation may be lessened with some treatments. Since the pink eye can spread quickly, getting a quick diagnosis and following the appropriate precautions can help contain its spread.

Causes of Conjunctivitis

The following are some causes of pink eye:

• Viruses.
• Bacteria.
• Allergies.
• A chemical splash on the face.
• A foreign body in the eye.
• A clogged tear duct in neonates.
• Conjunctivitis is caused by germs and viruses
• Pink eye is typically brought on by an adenovirus, though it can also be brought on by other viruses such as the varicella-zoster virus and herpes simplex virus.

Colds or signs of a respiratory infection, including a scratchy throat, can coexist with bacterial and viral conjunctivitis. Using improperly cleaned or borrowed contact lenses can result in bacterial conjunctivitis.

Both are extremely contagious. Through direct or indirect contact with the discharge from an infected person's eye, they can be disseminated. 

Allergic conjunctivitis

An allergic reaction to a trigger, such as pollen, causes allergic conjunctivitis, which affects both eyes. Your body makes a protein called immunoglobulin E (IgE) as a reaction to allergens. Histamines and other inflammatory chemicals are released by IgE-stimulated specific cells in the mucous lining of your eyes and airways. Many allergy symptoms, such as red or pink eyes, might be brought on by your body's release of histamine.

You might also sneeze frequently and have watery nasal discharge if you have allergic conjunctivitis, which also causes acute eye itching, tearing, and inflammation. Allergy eye drops can be used to manage the majority of allergic conjunctivitis. There is no spread of allergic conjunctivitis.

Irritation-related conjunctivitis

Conjunctivitis is also related to eye irritation from chemical splashes or foreign objects. Redness and discomfort can occasionally result from washing the eye out with water or a flush to remove an item or chemical. after most cases, symptoms, which may include watery eyes and a mucous discharge, go away on their own after a day or so.

Consult with your doctor or an eye specialist right away if flushing doesn't relieve the symptoms or if the substance is a caustic one, like lye. An eye injury from a chemical splash could be long-lasting. There may still be a foreign body in your eye if you continue to have symptoms. Another possibility is that your cornea or its membrane covering has been scratched.

Symptoms Of Conjunctivitis

The most typical signs of pink eye include:

• Either one or both eyes are red.
• Either one or both eyes are itchy.
• An uncomfortable feeling in one or both eyes.
• A discharge in one or both eyes that forms a crust throughout the course of the night and may make it difficult for your eye(s) to open in the morning.
• Tearing.
• the phobia of light, often called photophobia.

Types of Conjunctivitis

Acute Bacterial Conjunctivitis

• The signs exhibited by patients suffering from this type are the same as the general signs of conjunctivitis which include redness, pain, photophobia, discharge, etc.
• The treatment method to be undertaken depends upon the bacterial species which has resulted in conjunctivitis. 
• For investigating the causative agent of this type of conjunctivitis the following strategies can be used: 
• Microbiologically (stains) 
• PCR
•  Immunofluorescence microscopy
•  Biopsy

 Pseudomembranous Conjunctivitis   

• The signs exhibited by patients suffering from this type are the same as the general signs of conjunctivitis which include redness, pain, photophobia, discharge,etc. However, a characteristic sign of this type of conjunctiva is pseudomembrane formation which is mostly made of exudates and are adhering to the epithelial layer.
• The different causes that have been observed for pseudomembranous conjunctivitis are: 
• Bacterial Cause 
• Mild Diphtheria
• Streptococcus haemolyticus  
• Staph aureus 
• Gonococcus
• Viral cause – Severe Adenoviral 
• Herpes simplex
• Chemical irritants

Membranous Conjunctivitis

• In membranous conjunctiva, the membrane bleeds on peeling..
• The signs exhibited by patients suffering from this type are the same as the general signs of conjunctivitis which include redness, pain, photophobia, discharge, etc along with inflammatory membrane formation. 

Angular Conjunctivitis

This type of conjunctivitis involves the formation of 2 cantha along with excoriation of the skin. Moraxella Axenfeld has been the recurring cause of this type of conjunctivitis.

Some other pathogens also causing angular conjunctivitis are mentioned below:  

• M. Lacinata 
• M. Catartalis
• Staph aureus

Treatment  

The treatment method employed is the usage of antibiotic eye drops or zinc oxide solution. It Inhibits proteolytic enzymes.

Hemorrhagic Conjunctivitis    

• The signs exhibited by patients suffering from this type are the same as the general signs of conjunctivitis which include redness, pain, photophobia, discharge, etc along with subconjunctival hemorrhage. 
• Pneumococcus and Haemophilus have been observed to be the bacterial cause of hemorrhagic conjunctivitis. 
• Some viral strains like the Enters virus – 70, Adenovirus, Coxsackie – 24, and Echovirus – 34 have been observed to cause hemorrhagic conjunctivitis. 

The various causes which can lead to subconjunctival hemorrhage are:

• Trauma
• Hypertension (at least 3 times a day measurement) 
• Bleeding diathesis is common.
• The patient also experiences the sensation of a foreign body. 
• Contact lenses.
• Whooping cough

Trachoma 

• Trachoma is the occurrence of chronic conjunctivitis in children which is caused by Chlamydia trachomatis. It has different strains which are A, B, Ba, and C strain.

In the Active inflammatory stage: 

• Signs – The signs are itching and mucopurulent discharge. 
• On examination of the follicle on the upper palpebral conjunctiva and upper limbus, Herbert follicles are observed. Corneal vascularisation can also occur which is known as pannus and forms reti ridges. Corneal epithelial defects are also seen in this stage and papillary reaction is also present. 

The next stage of the infection is the Chronic Cicatricial stage

• Signs – In this stage follicles in the upper palpebral cause scarring which is known as Artt's line.
• Scarring also occurs in the upper limbus and is known as the Herbert's pits. Pannus is also seen
• Cicatricial entropium, Trichiasis, and Corneal opacity are also observed. 

Side Note: 

• WHO Grading

F - Grade 1 More than 5 follicles in the upper palpebral

I - Grade 2 Inflammatory

S - Grade 3 Scarring

T - Grade 4 Trichiasis

O - Grade 5 Corneal opacity

• Complication is Corneal ulcer

Pathology of Trachoma

• The pathology of trachoma can be done on the presence of the following structures: 
• Follicular and Papillary reaction 
• Intracytoplasmic inclusion bodies

Investigation of Choice 

• The investigative strategy of choice can be: 
  • PCR 
  • Mc cell culture coy
  • Giensus staining

Treatment

• The treatment method for trachoma is abbreviated as SAFE strategies, which are explained as follows: 
  • Surgery- Bilanical Tarsal Lobation
  • Antibiotics – Azithromycin (20 mg/kg), Tetracycline (1g/kg)
• Factors to employ the SAFE strategies in an area affected with trachoma are: 
• The prevalence of Trachoma follicles is observed and is more than 10% for children.
• If the prevalence is 5% to 10%, then only FE strategy is employed. 
• If the prevalence is less than 5% then no action iss taken.

Risk Factors Of Conjunctivitis

Risk factors for pink eye include:

• Exposure to a person with a bacterial or viral infection who has conjunctivitis.
• A possible cause of allergic conjunctivitis is exposure to an allergen.
• Wearing contact lenses, particularly those with a lengthy lifespan.

Treatment Of Conjunctivitis

Usually, the goal of treating pink eye is to reduce symptoms. Your supplier might advise:

• The use of synthetic tears.
• Utilizing a damp towel to clean your eyelashes.
• Many times a day, applying warm or cool compresses.
• You will be recommended not to wear contact lenses while undergoing therapy if you do. You should probably throw away any soft contacts you've previously worn, as advised by your doctor.

Prior to using them, disinfect hard lenses overnight. Inquire with your healthcare professional if you need to replace any contact lens cases or other accessories that you have used in the past or currently. Additionally, throw away any eye makeup you had on before being ill.

Typically, antibiotic eye drops are not necessary. Antibiotics won't help because viral infections frequently cause conjunctivitis.

By decreasing their future effectiveness or triggering a negative drug reaction, they might potentially be harmful. Rather, the virus needs time to spread throughout the body.

Within a few days, viral conjunctivitis frequently spreads from one eye to the other after starting in the first. Your symptoms ought to eventually go away by themselves.

If the herpes simplex virus is to blame for your viral conjunctivitis, antiviral medications can be a possibility.

Allergy conjunctivitis Treatment

If allergic conjunctivitis is the cause of the irritation, your doctor may recommend one of the numerous allergy-specific eye drops.

Antihistamines and mast cell stabilizers are examples of medications that can help manage allergic reactions. Decongestants, steroids, and anti-inflammatory eye drops are a few examples of the medications your doctor may prescribe to help manage inflammation.

These medications' over-the-counter counterparts might also work well. Find out which choice is best for you by asking your provider.

By avoiding whatever your sensitivities are to, you may be able to lessen the intensity of your allergic conjunctivitis symptoms.

Diagnosis Of Conjunctivitis

The majority of the time, your doctor can identify pink eye by asking you about your recent health history, symptoms, and eye exam.

Rarely, your doctor could remove a sample of the fluid that drains from your eye for a culture, a laboratory test. If your symptoms are severe or your doctor suspects a high-risk cause, like:

• A foreign object in your eye.
• An extremely harmful bacterial infection.
• A sexually transmitted illness.

Complications Of Conjunctivitis

Both toddlers and adults may have corneal discomfort from pink eye, which may impair vision. Your doctor should examine and treat you very away in order to reduce your chance of issues. Should this be the case:

• Eye pain.
• The sensation that something is obstructing your eyesight.
• The vision which is cloudy.
• Light sensitivity.

Prevention of conjunctivitis

Preventative measures for conjunctivitis include:

• Reduce the likelihood of pink eye.
• Stopping the spread of pink eye will help you maintain good hygiene. As an example:
• Keep your hands away from your eyes.
• Wash your hands regularly.
• Every day, use fresh towels and washcloths.
• Never swap out washcloths or towels.
• Regularly replace your pillowcases.
• Discard outdated eye makeup, such as mascara.
• Don't forget that pink eye is just as contagious as the ordinary cold. Returning to work, school, or child care is OK as long as you can maintain proper hygiene and stay away from close contact. However, it might be advisable to stay at home until your symptoms or those of your child clear up if your job, school, or child care requires close contact with others.

Xerophthalmia

It is a spectrum of ocular diseases due to Vitamin A deficiency.

WHO grading of xerophthalmia

The grading helps determine the severity of the condition. The signs are denoted by X and a subscript. They are 

• X_n → night blindness nyctalopia: the earliest sign
• X_1a → conjunctival xerosis
• X_1b → bitots spot
• X₂ → corneal xerosis
• X_3a → keratomalacia in less than one-third of the cornea
• X_3b → keratomalacia in more than one-third of the cornea (keratomalacia is liquefactive necrosis of cornea)
• X_s → cornea scarring
• X_f → xerophthalmia fundus → white spotted fundus and decreased amplitude in electroretinogram

Q. why do we see decreased amplitude in ERG?

Ans. ERG represents the activity of layers of rods and cones. Since xerophthalmia affects rods and bipolar cells, ERG shows a dip in amplitude.

Side notes:

More about bitots spot

Bitots spot: is keratinised epithelia and infection by corynebacterium xerosis. It is more common on the temporal side:

Pathological changes in xerophthalmia

• Loss of goblet cells
• Squamous metaplasia with keratinisation.

Treatment for xerophthalmia  

• Child more than one year: one lakh IU of vitamin A on the 0th, 1st, and 14th day
• Less than one year: half the dose
• Oral: double the dose of injectival vitamin A.  

Local treatment for xerophthalmia

• Intense lubrication: eyedrops containing methylcellulose derivatives or sodium hyaluronate
• Topical: retinoic acid 

Side note:

Other causes of nyctalopia

• Retinitis pigmentosa
• High myopia
• Late stage of primary open-angle glaucoma
• Congenital stationary night blindness (CSNB)
• Choroidal dystrophy: choroideremia and gyrate atrophy

Side notes:

Two forms of CSNB

1. fundus albi punctatus: night blindness with white spots in the fundus
2. Oguchi’s disease: night blindness with pale spots on the fundus.

Mezov’s phenomenon

Pale fundus restores its appearance when a person suffering from Oguchi’s disease stays in darkness for about an hour. The cause of the phenomenon is the overstimulation of rods.

 Pterygium

It is conjunctival degeneration characterised by triangular fibrovascular subepithelial ingrowth of bulbar conjunctiva over the limbus. It occurs commonly on the nasal side.

Clinical features

• Ugly appearance if it is not covering the pupil; otherwise, harmless. 
• Astigmatism
• Diminished vision when it encroaches on pupils.

Histopathology

• Elastotic degeneration of conjunctival stroma: similar to pinguecula.

Structure of Pterygial Formation

• Body: part from the triangle's base to the border of the pupil.
• Head: apical part of pterygium that protrudes into the pupil. and
• Avascular halo: the region around the tip: the destruction of bowman’s membrane by metalloproteinases.
• Stocker’s line occurs due to iron deposition near the head.

Causes  

• Exposure to UVB rays

Side note:

What else does UVB cause?

In addition to pterygium, it can cause phot ophthalmia, also called snow blindness → UVB rays reflect off the snow and cause corneal epithelial erosion.

Pseudo Pterygium

• It is a scarring that appears like pterygium.
• How to differentiate it from pterygium?
  • Glass rod test: if the glass rod passes through scarring, it is pseudo-pterygium.

Treatment

1. Bare sclera technique

• The recurrence rate after the bare sclera technique is 30 to 40%..
• Mitomycin C, an antimitotic drug administered preoperatively reduces the recurrence. 

2. Autografting

• It is the most effective modality  
• Procedure:

cut a portion of the conjunctiva in the upper or superior temporal quadrant, including limbal stem cells: 

↓

Stitch it over the affected area: conjunctiva at excised region regenerates.

3. Perfect 

• It stands for Pterygium Extended Resection Followed By Extended Conjunctival Transplantation.
• It is a modified version of autografting wherein the conjunctiva excised is much larger.

Pinguecula

It is a yellowish-white mound near the limbus formed by elastotic degeneration of conjunctival stroma

• It is commonly nasal.
• It does not extend on to the cornea.

Treatment

• Not needed: if asymptomatic.
• Mild steroids or lubricants: if presents itching
• Excision is an option but not preferable.

Dry Eye

• It is a condition caused by impaired functions of any layer of the tear film. It becomes a disease with the onset of ocular inflammation.
• Dysfunction of any of the three layers of tear film causes inadequate volume, unstable secretion, or dysfunction in the tear.

Layers of Tear Film After Cornea

1. Mucin layer: formed of goblet cells of conjunctiva → helps spread tear over the ocular surface
2. Aqueous layer: thickest layer: formed of lacrimal and accessory lacrimal glands→ lubrication.
3. Lipid layer: formed by meibomian glands in the lens → prevents evaporation of tear.

Keratoconjunctivitis Sicca

Keratoconjunctivitis sicca is the deficiency of the aqueous layer.

• KCS + Xerostomia primary: Sjogren syndrome.
• Primary Sjogren syndrome + connective tissue disorder: secondary Sjogren syndrome

Side note:

Ocular Features of Rheumatoid Arthritis

Rheumatoid arthritis is a connective tissue disorder, and its association with keratoconjunctivitis sicca leads to secondary Sjogren syndrome. Hence, patients with rheumatoid arthritis experience dry eye disorder.

 Clinical Manifestations of Dry Eye

• Burning sensation
• Gritty sensation of foreign bodies
• Excessive mucus deposition
• Diminished vision when precorneal tear film involved
• Tear meniscus height lesser than 0.25 mm.
• Punctate epithelial keratitis
• Mucus filaments

Investigation of Dry Eye Disorder

• Slit lamp examination

To visualise tear meniscus height, which is the length of a triangular cross-section between lower lid margin and cornea. 

• Schirmer’s test
  • Schirmer’s test 1 
    It involves placing Whatman paper No. 41 under the lower lid for 5 minutes: 
    Wet length of less than 15mm indicates dry eye. 
    It measures both basal and reflex secretion.
• Schirmer’s test 2
  Measures only basal secretion using topical anaesthesia.
• Phenol red thread test
  Yellow-colored thread is brought in contact with the eye for 15 seconds, and the length of the stain that turns red is measured.
  Less than 6 mm indicates severe dry eye.
• Tear film break-up time 
  • It is the time taken for a dry spot to appear from the last blink.
  • Less than 10 seconds indicates severe dry eye.

• Rose Bengal or lissamine green staining

They help visualize dead cells and mucus.

• Tear constituent

Low levels of lactoferrin indicate dry eye.

• Impression cytology

Measures the number of goblet cells.

• Tear osmolality measurement

A high value indicates a dry eye.

Treatment

Treatment is either medical or surgical

That is everything you need to know about Allergic Conjunctivitis for your Ophthalmology preparation. For more interesting and informative blog posts like this download the PrepLadder App and keep reading our blog!