<Things you should know> The correct knowledge about conjunctivitis: Causes, symptoms, and treatment of conjunctivitis What is conjunctivitis? Main types/causes/symptoms of conjunctivitis Conjunctivitis Prevention and Treatment Methods by Type The relationship between conjunctivitis and contact lenses Serious complications of conjunctivitis Treatment and prevention methods for conjunctivitis in children and the elderly Many people have likely experienced rushing to the ophthalmologist because their whites of the eyes were red and bloodshot. While conjunctivitis is often thought of as a childhood illness or something easily transmitted, there are several different types. The causes, symptoms, and treatments vary. Here, we explain the most common types of conjunctivitis, supervised by an ophthalmologist. What is conjunctivitis? Conjunctivitis is a condition in which the conjunctiva, the translucent membrane covering the whites of the eyes and the inside of the eyelids, becomes inflamed due to various irritations or microbial infections. Symptoms vary depending on the cause, but may include redness of the conjunctiva, excessive discharge, eyelid swelling, and itching. How conjunctivitis works The conjunctiva plays a role in preventing bacteria, viruses, and other pathogens from entering the eye. When you have conjunctivitis, your eyes become red and discharged, which is the conjunctiva's defense mechanism to eliminate foreign substances. If the epithelial cells of the conjunctiva (the cells that make up the epithelial tissue) are healthy, inflammation will not occur from mere contact with bacteria or viruses. However, if you have dry eyes or if you rub your eyes too hard and damage the epithelial cells of the conjunctiva, bacteria and viruses can adhere to the damaged area and cause inflammation. Conjunctiva: The entire area from the inside of the eyelid to the white of the eye. Main types/causes/symptoms of conjunctivitis Conjunctivitis is mainly divided into three types: allergic conjunctivitis, bacterial conjunctivitis, and viral conjunctivitis. Let's look at the causes and symptoms of each. Allergic conjunctivitis It occurs when the eyes become sensitized to allergens (substances that trigger allergic reactions) such as pollen and house dust. *1 Symptoms include itching, conjunctival redness, tearing, and eye discharge, but nasal symptoms such as sneezing, runny nose, and nasal congestion may also occur. There are two types: "seasonal allergic conjunctivitis (mainly caused by pollen)" which occurs in specific seasons such as spring and autumn, and "perennial allergic conjunctivitis (mainly caused by house dust)" which can occur regardless of the season. *1 Sensitization: The process by which the immune system reacts to allergens, leading to a predisposition to allergic reactions. bacterial conjunctivitis It is caused by a bacterial infection of the eye. The bacteria that cause it are diverse, ranging from weak bacteria that can be washed away by tears to bacteria that can cause serious illness, such as Staphylococcus aureus. Symptoms include redness and swelling of the whites of the eyes, and yellowish discharge. It also includes "chlamydial conjunctivitis," a type of sexually transmitted infection caused by the bacterium Chlamydia trachomatis, which is transmitted when the eyes come into contact with the bodily fluids of an infected person. Viral conjunctivitis It is caused by a viral infection. The symptoms vary depending on the virus, so let's take a closer look. Epidemic keratoconjunctivitis (pink eye) Adenovirus (types 8, 19, 37, etc.) infects the eyes, causing this condition. Due to its high infectivity, it is also called "pink eye." Symptoms include redness of the eyes, discharge, tearing, eye pain, and swollen lymph nodes. Pharyngoconjunctivitis (pool fever) This illness is caused by adenovirus (such as type 3) infecting the eyes. It is often spread among children through swimming pools, hence it is also called "pool fever." Eye symptoms such as redness and discharge are milder than those of "epidemic conjunctivitis," and other symptoms include sore throat and fever (around 39 degrees Celsius). acute hemorrhagic conjunctivitis It is mainly caused by enterovirus 70 and a variant of coxsackievirus A24 infecting the eyes. Symptoms are acute, including redness, discharge, and a gritty feeling in the eyes, and bleeding in the whites of the eyes is often seen. It once caused epidemics all over the world, but in recent years, there have been no major outbreaks in Japan except in Okinawa Prefecture. Herpetic conjunctivitis This condition is caused by the herpes simplex virus infecting the eyes. The symptoms are indistinguishable from adenovirus conjunctivitis (viral conjunctivitis, pharyngoconjunctivitis). It is characterized by the formation of typical dendritic lesions on the cornea. Both eyes are rarely affected, and small blisters may be seen on the skin around the eyes. Conjunctivitis Prevention and Treatment Methods by Type The best way to prevent conjunctivitis is to keep the causative allergens, bacteria, and viruses out of your eyes. This article explains specific prevention methods and how to treat conjunctivitis, categorized by type. Prevention and treatment of allergic conjunctivitis We all want to avoid unpleasant symptoms such as itching and redness. This article explains prevention and self-care. Use eye drops Allergic conjunctivitis can be treated with over-the-counter (OTC) medications *2. Eye drops containing anti-allergic agents or antihistamines are effective. *2 Medications that can be purchased without a prescription at pharmacies and drugstores. Avoid contact with pollen. During pollen season, try to minimize contact between your cornea and nasal mucosa and pollen. When pollen levels are high, it's a good idea to avoid going outside, or wear goggles or a pollen-blocking mask when you do go out. Remove mites Remove dust mite carcasses and droppings by using a powerful vacuum cleaner to vacuum slowly and carefully, vacuuming futons after sun-drying or using a futon dryer, and using an air purifier. In addition, maintaining a room temperature of 20 degrees Celsius or lower, humidity of 50%, and good ventilation will suppress the proliferation of dust mites *. Using an air purifier is also effective. Remove mold In summer, focus on dehumidifying and keeping humidity below 70% will help suppress mold growth *. In winter, condensation on windowpanes and frames can cause mold, so wipe them frequently and use insulation to prevent condensation. Avoid washing your eyes with tap water. If you want to wash away pollen or house dust that has gotten into your eyes, using tap water can wash away your tears and potentially damage your cornea. It's best to use preservative-free artificial tears. *Reference: Japanese Ophthalmological Society, "Guidelines for the Treatment of Allergic Conjunctival Diseases (2nd Edition)" Prevention and treatment of bacterial conjunctivitis Bacterial conjunctivitis is caused by a bacterial infection of the eye. Those with weakened immune systems should be especially careful. Wash your hands frequently. Bacterial conjunctivitis is transmitted through the hands, so it's important to wash your hands frequently and avoid touching your eyes with dirty hands. Always wash your hands when putting in or taking out contact lenses. Use eye drops Bacterial conjunctivitis can be treated with over-the-counter (OTC) medications *2. If your condition does not improve after using antibacterial eye drops for 3-4 days, consult an ophthalmologist. *2 Medications that can be purchased without a prescription at pharmacies and drugstores. Prevention and treatment of viral conjunctivitis Some strains are highly contagious, so it's important not only to avoid getting infected yourself, but also to avoid spreading it to others. Wash your hands thoroughly and do not rub your eyes. Many viruses are present in tears and eye discharge. Most cases of viral conjunctivitis are transmitted through contact with hands that have rubbed the eyes of an infected person. To prevent infection and avoid spreading it to others, it is important to wash your hands thoroughly with running water and soap and to avoid rubbing your eyes. Use goggles in the pool. Pharyngoconjunctivitis (also known as swimming pool fever) can be transmitted when the virus, contained in the eye discharge, nasal mucus, or feces of an infected person, enters the body through swimming pool water. While rinsing the eyes after swimming was once recommended, rinsing with tap water can wash away tears and damage the cornea, so this should be avoided. Currently, wearing goggles is recommended. Visit an ophthalmologist. There are no eye drops specifically for epidemic keratoconjunctivitis (pink eye) or pharyngoconjunctivitis (pool fever). You should see an ophthalmologist immediately. An ophthalmologist will usually prescribe eye drops to reduce inflammation and prevent secondary bacterial infections.In infants and young children, if keratitis caused by epidemic keratoconjunctivitis becomes severe, corneal opacity may remain even after symptoms improve, potentially leading to amblyopia (lazy eye). Therefore, it is important to continue visiting the doctor until complete recovery is achieved. Prevent infection to others Epidemic keratoconjunctivitis (pink eye) and pharyngoconjunctivitis (pool fever) are highly contagious and are therefore designated as Category 3 infectious diseases in schools under the School Health Act. ■ Home recovery You should stay home for 1 to 10 days to recover from the risk of infection. You can return to school, kindergarten, or daycare only after receiving permission from a doctor. Adults should also take time off work. Particular caution is needed in customer service and food service industries, as there is a high risk of infecting others. ■ Prevent infection among family members Remember to wash your hands frequently, avoid rubbing your eyes, and do not share towels or eye drops. If someone in your family is infected, it is also recommended to use paper towels instead of regular towels. Wipe down anything that an infected person has touched with alcohol. Also, since infection can occur through hot water, infected people should take their bath last. Afterwards, thoroughly clean the bathtub and faucets. The relationship between conjunctivitis and contact lenses Contact lens contamination can be caused by external factors such as cosmetics, dust, and cigarette smoke, as well as internal factors such as proteins and lipids in tears. People with severe allergic conjunctivitis symptoms tend to have more internal secretions, making their lenses more prone to contamination. Additionally, allergic reactions can occur to the contact lens material or to protein deposits and other contaminants that accumulate on the lenses. If you experience eye discharge, it's generally best to take a break from wearing contact lenses. Continuing to wear them could worsen the condition. Serious complications of conjunctivitis When you have conjunctivitis, the epithelial cells of the conjunctiva are damaged, making it easier for viruses or bacteria of a different type than the one that caused the conjunctivitis to invade. When bacteria infect a weakened conjunctiva caused by viral conjunctivitis, the condition can become severe depending on the type of bacteria. This condition is called "mixed infection." Furthermore, persistent keratitis as a sequela of adenovirus conjunctivitis can lead to vision loss. It is important not to ignore conjunctivitis and to ensure it is completely cured. Treatment and prevention methods for conjunctivitis in children and the elderly When you are healthy and your immune system is functioning normally, you will not get infected even if the virus comes into contact with your eyes. However, children with immature immune systems, the elderly with weakened immune systems, and people who are ill or recovering from illness are more susceptible to infection, so caution is necessary.Thorough handwashing, attention to diet and sleep, and avoiding overwork are essential to prevent a weakened immune system. Furthermore, dry eyes and conjunctivitis, which can damage the cornea and conjunctiva, make you more susceptible to bacterial infections, so it's important not to neglect these conditions. Supervised by: Dr. Masayoshi Kajita, Director of Kajita Eye ClinicAfter graduating from Fukushima Medical University in 1983, he worked as a researcher at the University of California, Berkeley, before opening Kajita Ophthalmology Clinic in 2003. From 2018 to 2021, he served as a Clinical Professor at Tokyo Medical and Dental University School of Medicine. In 2022, he was awarded Honorary Membership by the Japan Contact Lens Society, and in 2023, Honorary Membership by the Japanese Society of Ophthalmic Optics. He currently serves as a councilor of the Japan Ophthalmological Society and a member of the drafting committee for the Japanese Medical Optics JIS standards. We take care to post accurate information,Please point out any incorrect information. Please submit any comments regarding medical information here. Return to the list of eye symptoms and diseases