Pink eye (conjunctivitis): types, spread and care, a review

Red, sticky or itchy eyes can be signs of conjunctivitis, also called pink eye. This article explains the types, how it spreads, what helps and when to get medical advice, using information from the NHS and the US CDC.

1. Introduction

Conjunctivitis causes redness or swelling of the white of the eye or the inside of the eyelid. This makes the blood vessels easier to see, so the eye looks pink or red ^[2]. The CDC describes it as one of the most common and treatable eye conditions ^[2]. The NHS says it usually gets better within a couple of weeks without treatment ^[1].

2. Causes and types

The most common causes are viruses, bacteria and allergens, which are things such as pollen or pet dander that trigger an allergy ^{[1, 2, 3]}. Other causes include chemicals, contact lens wear and a foreign object in the eye, such as a loose eyelash ^[2]. The NHS also notes that some sexually transmitted infections can cause conjunctivitis, which takes longer to clear ^[1].

• Viral: very contagious, and antibiotics do not work against it ^{[2, 3]}. The NHS says red, gritty eyes are usually contagious ^[1].
• Bacterial: very contagious ^[2]. Pus discharge can occur, and the NHS says conjunctivitis with sticky pus is contagious ^{[1, 3]}.
• Allergic: linked with allergies such as hay fever. It makes eyes red and watery and is not contagious ^[1].

3. Signs and symptoms

Symptoms can affect one eye or both and vary with the cause. They include ^{[1, 2]}:

• Pink or red colour in the white of the eye
• Burning, grittiness or itching, and an urge to rub the eye
• Watery eyes
• Swollen eyelids
• Discharge, which may be pus or mucus and may stick to the lashes

4. Diagnosis and tests

Providers usually diagnose pink eye by examining the eye and asking about your history and symptoms. They may sometimes take a sample from the eye for lab testing ^[3]. The NHS says conjunctivitis with sticky pus is contagious, red and gritty eyes are usually contagious too, and the allergic type, which is triggered by allergies such as hay fever, is not ^[1]. A pharmacist can suggest eyedrops or antihistamines ^[1]. A doctor should be seen when the patient is a baby, when symptoms are severe or not improving, or when the immune system is weak ^{[1, 3]}. The NHS notes that eye pain, light sensitivity and vision changes may signal a more serious eye problem, so these signs need a medical check ^[1].

5. Treatment and management

Treatment depends on the cause, and your doctor or pharmacist decides what is suitable ^{[1, 3]}.

• Viral: usually mild and clears in about 7 to 14 days, although it can take two to three weeks. Antibiotics do not help. Doctors may prescribe antiviral medicine for serious forms, such as those caused by herpes simplex or varicella-zoster virus ^[3].
• Bacterial: mild cases may improve in two to five days without antibiotics. Doctors may prescribe antibiotic eye drops or ointment, especially when there is pus discharge or the immune system is weak. Antibiotics can shorten the infection and reduce spread ^[3].
• Allergic: the first step is to avoid the trigger. Allergy medicines and special eye drops may help ^[3].

Home care that official sources describe ^{[1, 3]}:

• Wash the eyelids with cooled boiled water, using a clean cotton wool pad for each eye to remove crusts.
• Hold a cold flannel or compress on the eyes for a few minutes to soothe them.
• Use artificial tears, available without a prescription, for dryness.
• Do not wear contact lenses until your eyes have healed or an eye doctor says it is safe.

For a child under 2, the NHS says treatment needs a prescription from a GP ^[1].

6. Prevention and self-care

Infectious types spread easily from person to person. The NHS suggests these steps ^[1]:

• Wash your hands often with warm soapy water.
• Do not share towels or pillows, and wash pillowcases and face cloths in hot water.
• Cover your mouth and nose when sneezing and throw away used tissues.
• Avoid rubbing your eyes.

Children and adults usually do not need to stay away from school or work unless they feel very unwell ^[1]. The CDC advises staying home if symptoms persist or if your work or school involves close contact with others, and returning with your doctor's approval ^[2].

7. When to see a doctor

Get medical help promptly for a newborn baby with any red or sticky eyes. The NHS says a baby under 30 days old needs an urgent appointment ^{[1, 2]}. Newborn eye infections can be very serious ^[2]. Adults and children should also be seen if there is ^{[1, 3]}:

• Eye pain or sensitivity to light
• Blurred vision that does not clear after wiping away discharge, or vision changes such as wavy lines or flashing
• Very red eyes, or symptoms that get worse
• No improvement after seven days (NHS), or after 24 hours of antibiotic treatment for a bacterial infection (CDC)
• A weak immune system, or contact lenses with spots on the eyelids

In an emergency, call your local emergency number (112 in India, 911 in the United States).

8. Conclusion

Pink eye is common, and mild cases often clear on their own, but the cause matters: viral and bacterial forms spread, while allergic forms do not. Simple hygiene and home care help most people, and a doctor should see babies and anyone with pain or vision changes. Your doctor decides whether antibiotics are right.