Conjunctivitis or often called pink eye is an inflammation (swelling) of the conjunctiva; the thin layer that lines the inside of the eyelid and covers the white part of the eye. It can affect both eyes making them appear red and produce more water and mucus.

There are three main types of conjunctivitis which are allergic conjunctivitis which results from direct exposure to an allergy trigger, infectious conjunctivitis that results from bacterial or viral infection, and chemical conjunctivitis which is caused by irritant substances.  Having direct contact with any conjunctivitis puts the individuals at a risk of getting conjunctivitis. 

Related conjunctivitis vary according to the cause or the type. However, all conjunctivitis types share these common signs and symptoms redness, itchiness, gritty feeling, a discharge that forms a crust during the night, and tearing.

Conjunctivitis diagnosis is based on a comprehensive eye examination that includes the patient’s history, visual acuity measurements, evaluation of the conjunctiva and external eye tissue, evaluation of the inner structures of the eye, and supplemental testing.

Prevention is relatively achieved by repeated hand washing and maintaining cleanness. Treatment depends on the underlying cause. In the majority of viral cases, there is no specific treatment. Most cases that are due to a bacterial infection will also resolve without treatment while antibiotics can shorten the illness. In allergic conjunctivitis, the first treatment procedure is to stay away from allergy triggers.  Viruses cause up to 80% of all cases of acute conjunctivitis.

The conjunctiva is a thin transparent membrane contouring the inner surface of the eyelid and covering the white part of the eye. Conjunctivitis is an inflammation or an infection in the small blood vessels in this part which leaves the white part of the eye reddish or pinkish.

There are three main types of conjunctivitis:

• Allergic Conjunctivitis

People with seasonal allergy are usually affected by this type of allergies since it occurs from direct contact with a triggering substance that leads to an allergic reaction in the eye.

One of the types of allergic conjunctivitis is giant papillary conjunctivitis which is caused by the chronic presence of a foreign body in the eye. People who are more comprised to develop giant papillary conjunctivitis are the following, people who wear hard or rigid contact lenses, those who wear soft contact lenses and do not often replace them, people with an exposed suture on the surface of the eye or are with a prosthetic eye.

• Infectious Conjunctivitis

It is caused either by a bacteria or virus.

• Chemical Conjunctivitis

Chemical conjunctivitis occurs when an individual is exposed to irritants like air pollution, chlorine in the swimming pool, and noxious chemicals.

The three most common causes of this inflammation are as follows:

• Infection

Infective conjunctivitis can be caused by a bacteria or a virus. Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus species, or, less commonly, Chlamydia trachomatis, can all be the cause of a bacterial infection. Different viruses, such as adenoviruses can cause viral conjunctivitis. 

• Allergic reaction

Allergic conjunctivitis could be caused by some allergic reactions, such as: Pollen from trees.

Plants.

Grasses.

Weeds.

Dust mites.

 Molds.

Dander from pets.

Medicines.

Cosmetics.

• Irritating the conjunctiva

Any type of irritants can cause chemical conjunctivitis such as the presence of a foreign body in the eye or coming in contact with chemicals, fumes, smoke, or dust.

The following factors increase the possibility for conjunctivitis to occur:

• Directly contacting a person infected with viral or bacterial conjunctivitis.
• Being exposed to environmental factors that can trigger an allergic reaction in the eye.
• Using contact lenses.

Bacterial conjunctivitis

The patient can be infected with bacterial conjunctivitis through one of these pathways:

•  Direct infection by the bacteria.

• Abnormal multiplication of the native conjunctival flora.

• Spread of infection from the organisms in the patient's nasal and sinus mucosa.

Bacteria penetrate the conjunctival epithelial layer and sometimes the substantia propria as well. Factors that guide the pathology include direct infection and inflammation of the conjunctiva surface, bystander effects on adjacent tissues such as the cornea, and the host's acute inflammatory response and long-term reparative response.

The most common pathogens for bacterial conjunctivitis in adults are staphylococcal species. Streptococcus pneumoniae and Haemophilus influenza come in next. In children, the disease is often caused by H influenza, S pneumonia, and Moraxella catarrhalis.

Viral conjunctivitis

Primary Herpes simplex virus infection abbreviated as HSV infection in humans happens as a nonspecific upper respiratory tract infection. HSV spreads from infected skin and mucosal epithelium through sensory nerve axons, a long slender projection of a nerve cell, or neuron, conducting electrical impulses away from the neuron's cell body to establish latent infection in associated sensory trigeminal nerve  and it´s ganglia. This infection occurs in the absence of recognized primary infection, and the virus reactivation may follow any route of the three branches.

Allergic conjunctivitis

Allergic conjunctivitis is an inflammation of the ocular surface that occurs as a response to a transient allergen, or a persistent allergen such as pollen in seasonal allergic conjunctivitis and house dust mite in peren­nial allergic conjunctivitis, respectively.

Seasonal allergic conjunctivitis (SAC) is a type I hypersensitivity response; occurs when a sensitized individual comes in contact with a specific[FA1]  antigen, with conjunctiva activated mast cells as a direct result of allergen cross-linking of surface of immunoglobulin E (IgE) receptors since IgE have a strong affinity for mast cells and mast cells degranulation is triggered by the antigen that causes the cross-linking of two adjacent IgE molecules, resulting in degranulation and release of histamine, leukotrienes, proteases, prostaglandins, cytokines, and chemokines. Vascular leakage is induced by the release of these substances which is followed by cellular infiltration of eosinophils and neu­trophils and edema. T-cell infiltration can be absent or shown in small amounts.

In perennial allergic conjunctivitis (PAC), eosinophils, neutrophils, and a small number of T cells are responsible for the conjunctival tissue infiltration.  These cells are drawn into site of inflammation during the persistent, allergen-driven inflammatory response via the release of chemokines .

Two main symptoms of conjunctivitis are observed:

• Eye redness

An inflammation or widening of the blood vessels of the conjunctiva leads to eye redness.

• Discharge

Glands of the conjunctiva contain thousands of cells that are responsible for producing mucus and tiny glands that produce tears. When these glands become inflamed, they become overactive, producing more water and mucus.

Depending on the cause, other symptoms may occur:

• Infective conjunctivitis

• Viral Conjunctivitis

• It is caused by cold, flu, or other respiratory infection symptoms.
• Usually one eye gets infected and within days, it may spread into the other eye.
• A watery rather than a thick discharge from the eye is present.

• Bacterial Conjunctivitis

• Usually one eye gets infected and may spread into the other eye.  The discharge in this case is in a pus form that is a yellow-green color.
• It can occur with an ear infection, in some cases.

• Allergic Conjunctivitis

• Both eyes are usually affected.

•  Intensified itching, tearing, and swelling in the eyes can result from allergic conjunctivitis.

• Symptoms of allergy such as an itchy nose, sneezing, a scratchy throat, or asthma may accompany this case.

• Chemical conjunctivitis

• Watery eyes and mucus discharge are produced.

A comprehensive eye examination diagnoses conjunctivitis. Testing, with special emphasis on the conjunctiva and surrounding tissues, may include:

• Patient medical history

Information from the patient is collected about when the symptoms started to appear, and whether any general health or environmental conditions have an input to the problem so that symptoms can be determined.  

• Visual acuity measurements

The vision is tested for being affected or not in this test.

• Evaluation of the conjunctiva and external eye tissue

This technique uses bright light and magnification.

• Evaluation of the inner structures of the eye

This technique is used to rule out other tissues being affected by the condition.

• Supplemental testing

Cultures or smears of the conjunctiva tissue are collected, which is critical in cases of chronic conjunctivitis or when the condition is not responding to treatment.

Treating procedures of conjunctivitis have three main goals:

• The patient’s comfort is increased.
• The course of the infection or inflammation is reduced.
• In contagious forms of conjunctivitis, the spread of the infection is prevented.

The type of conjunctivitis determines the recommended medications therapy as follows:

• Allergic conjunctivitis

In this type, the elimination of the allergic cause from the patient’s environment is the first thing to do. In mild cases, cool compresses and artificial tears aid in relieving the discomfort severe cases usually require non-steroidal anti-inflammatory medications and antihistamines. People with persistent allergic conjunctivitis are requested to use topical steroid eye drops .2

• Infectious Conjunctivitis

• Bacterial conjunctivitis

In order to shorten the length of bacterial conjunctivitis, reduce complications, and reduce the spread of infection to others, antibiotic eye drops such as sodium sulfacetamide or azithromycin or ointments such as erythomycin, bacitracin, or neomycin are used to treat bacterial conjunctivitis. The improvement of bacterial conjunctivitis is observed after three or four days of treatment, but patients need to complete the course of antibiotics in order to prevent recurrence.2, 5

• Viral conjunctivitis

Drops or ointments or any type of antibiotics are unable to treat viral conjunctivitis. However, symptoms can often be relieved with cool compresses and artificial tear solutions, in addition to antiviral medications such as acyclovir or trifluridine or artificial tears19 when the disease is caused by the herpes simplex virus. The discomfort from inflammation in severe cases is reduced by the topical steroid drops  keeping in mind that the time of infection will not be shortened by these drops since the virus has to run its course, which may take up to two or three weeks.

• Chemical conjunctivitis

Careful flushing of the eyes with saline and with topical steroids is the standard procedure for treatment in chemical conjunctivitis.  Scarring, damage to the eye or vision, or even loss of the eye are seen in severe chemical injuries, especially alkali burns which are considered medical emergencies.  

Complementary and Alternative Therapies

Symptoms are relieved using alternative therapies. The used solution or compress should be sterile. Mild cases of conjunctivitis require the patient to start treatment with compresses, where warm compresses are used for infective conjunctivitis while cold compresses are used for allergic or irritative conjunctivitis. Moderate cases oblige the patient to use a compress and an eye wash that is delivered as a pre-mixed eye wash solution in a sterilized package or from a competent herbal practitioner.

• Nutrition and Supplements

Oral vitamin C and zinc supplements should be taken for a whole week and under the doctor's supervision which help in strengthening the immune system and speeding up the healing process.  

Complications of conjunctivitis

The possible complications depend on the causative agent of conjunctivitis:

• Infectious conjunctivitis

Infectious conjunctivitis which are caused by any type of bacteria will lead to a number of complications especially in premature babies which are:

• Meningitis 

Which is an infection of the protective membrane which surrounds the brain and the spinal cord (meninges).

• Cellulitis

It is an infection of the deep layer of the skin and tissue that leads to a sore and inflamed skin on the surface.

• Septicemia

This happens when the bacteria enters the bloodstream and attacks the body's tissues which is commonly known as blood poisoning.

• Otitis media

Haemophilus influenza bacteria is responsible for causing this type of infectious conjunctivitis that leads to this short-term ear infection affecting children.

The case is different in newborn babies with infectious conjunctivitis where it can lead to a severe and rapidly progressive eye infection. If it went untreated, it can cause permanent damage to the child’s vision.

• Allergic conjunctivitis

Very rare serious complications are seen when conjunctivitis is caused by an allergic reaction to pollen, dust mites or similar. However, the quality of life is affected because once the patient is exposed to the causes, symptoms will be triggered.  

 Good hygiene practices to be followed can help control the spread of conjunctivitis including:

• Avoid touching or rubbing the infected eye which can worsen the condition or help spread it into the other eye.

• Frequent washing of the hands with soap and warm water, especially before and after cleaning, or applying eye drops or ointment to the infected eye. Alcohol-based hand sanitizers can replace soap and water when they are not available.  

• The discharge around the infected eye should be washed several times a day after cleaning the hands and using a wet washcloth or a fresh cotton ball. The used cotton balls should be disposed of after use while the used washcloths should be washed with hot water and detergent. Upon completing this cleaning procedure, repeated washing of the hands should be done with soap and warm water.

• Separate eye drop dispensers/bottles should be used for the infected and non-infected eyes.

• Pillowcases, sheets, washcloths, and towels should be often washed in hot water and detergent, in addition to washing the hands post handling such items.

• Going back to wearing contact lenses should only be resumed when an infected eye is completely cured and upon the doctor’s instructions.

• Clean eyeglasses, paying attention not to contaminate items (like hand towels) that might be shared by other people.

• Contact lenses should be cleaned, stored, and replaced according to the eye doctor’s instructions.

• Personal items should not be shared such as pillows, washcloths, towels, eye drops, eye makeup, face makeup, makeup brushes, contact lenses, contact lens containers, and eyeglasses.

• Do not use swimming pools.

• Complete the time for the course of the antibiotic.

• Decreasing the risk of getting infected with conjunctivitis from an infected person can be  done by the following steps:

• Frequent washing of the hands with soap and warm water. Alcohol-based hand sanitizers can replace soap and water when they are not available. Washing the hands should be done with soap and warm water after coming in contact with an infected person or items he or she uses.

• The eye shouldn’t be touched by unwashed hands.

• Items used by an infected person shouldn’t be shared; for example, do not share pillows, washcloths, towels, eye drops, and eye or face makeup, makeup brushes, contact lenses, contact lens containers, or eyeglasses.11

Avoiding re-infection once the infection resolves can be done using these steps:

• Throw away and replace any eye or face makeup used while infected.

• Throw away contact lens solutions that were used while the eyes were infected.

• Disposable contact lenses should be thrown away, especially if they were used during an eye infection.

• Clean extended wear lenses as directed.

• Clean eyeglasses in case that they were used while infected.

The health of an individual is improved with treatment. Recurring infections are possible if no steps are taken to prevent its spreading.

Conjunctivitis caused by viruses or bacteria can spread through contact. These have been known to spread through entire households or classrooms.

Patients who are infected with bacterial conjunctivitis have typically mild cases and can last as few as 2 -3 days or up to 2 - 3 weeks. Many cases improve in 2 - 5 days without treatment.  However, topical antibiotics are often prescribed to treat the infection.

Viral conjunctivitis is typically mild and usually clears up in 7 - 14 days without treatment and resolves without any long - term effects. If complications occur in some cases, it may require 2 - 3 weeks or more for viral conjunctivitis to completely clear up.

Symptoms of allergic conjunctivitis often go away with treatment. However, they are persistent if the patient continues to be exposed to the allergen.18

Vernal conjunctivitis is a long-term (chronic) swelling of the outer lining of the eyes that may occur in those with chronic allergies or asthma. . It is most common in young males, and most often occurs during spring and summer.13, 16

As reported in The Journal of the American Medical Association, up to 80% of all cases of acute conjunctivitis are caused by viruses and adenoviruses causes 65% and 90% of cases of viral conjunctivitis. Herpes simplex virus forms 1.3% to 4.8% of all cases of acute conjunctivitis. The incidence of bacterial conjunctivitis was estimated to be 135 in 10 000. Almost 40% of the population are affected by allergic conjunctivitis but only a small proportion gets medical care.