- A virus consists of a core of nucleic acid (DNA or RNA) surrounded by a coat of antigenic protein.
- The virus provides the genetic code for replication, whereas the host cell provides the energy and raw material for the virus to grow.
- Bacteria are single cell organisms that do not have a nucleus and are among the most simple and most
abundant life forms on earth.
- antibiotics are effective against bacterial infections, not viruses.
- Bacteria grow OUTSIDE the host cell and can be attacked by antibiotics
What is blepharitis?
- a common condition that causes inflammation of the eyelids.
- tends to recur.
What causes blepharitis?
Blepharitis occurs in two forms:
Anterior blepharitis Posterior blepharitis..
- Affects the outside front of the eyelid, where the eyelashes are attached.
two most common causes of anterior blepharitis are
- bacteria (Staphylococcus)
- scalp dandruff.
- Affects the inner eyelid (the moist part that makes contact with the eye) caused by problems with the oil (meibomian) glands in this part of the eyelid.
Two skin disorders can cause this form of blepharitis:
- acne rosacea, which leads to red and inflamed skin,
- scalp dandruff (seborrheic dermatitis).
What are the symptoms of blepharitis?
- dry eye
- foreign body
- burning sensation
- excessive tearing
- sensitivity to light (photophobia)
- red and swollen eyelids,
- redness of the eye
- crusting of the eyelashes on awakening.
What other conditions are associated with blepharitis?
- painless firm lump caused by inflammation of the oil glands of the eyelid.
- involves keeping the lids clean and free of crusts.
- warm compresses should be applied to the lid to loosen the crusts, followed by a light scrubbing of the eyelid with a cotton swab and a mixture of water and baby shampoo.
- Patients who also have acne rosacea should have that condition treated at the same time.
- Allergy eyes or allergic conjunctivitis is the irritation of the conjunctiva, or covering of the eyeball, as a reaction to an allergic substance to which one is sensitive. Allergic conjunctivitis, which is not contagious, causes one’s eyes to become watery, red, swollen, itchy, and often painful. This condition, which is may also be called allergy eyes, might possibly either immediately impact a person, or affect them after a period of time.
- There are two types of allergic conjunctivitis, seasonal and perennial.
Seasonal allergic conjunctivitis affects people during specific seasons of the year while perennial allergic conjunctivitis impacts people throughout the year. Allergic conjunctivitis can cause much discomfort due to the symptoms listed above. In adds to, untreated allergic conjunctivitis might possibly cause someone to commonly rub his/her eyes, which could lead to permanent eye damage.
Allergic Conjunctivitis Causes
- As noted, allergic conjunctivitis is not contagious. A person develops the condition when exposed to an allergic or sensitive substance, may also be called an allergen. Trees, grass, weeds, and flowers release the allergen pollen into the air. During the spring and fall months, pollen levels are at their highest. The allergen mold is also released through the air, from substances such as leaves, grass, and hay. It can also develop in damp atmospheres within the home, such as the kitchen or bathroom.
- A dog or cat’s dander, or skin flakes, as well as its saliva and urine can be powerful allergens. Although the actual hair of a pet is not considered a powerful allergen itself, the pet’s hair or fur can collect mold, pollen, and dust.
- Dust mites, tiny bugs that are related to spiders and ticks, also cause allergic conjunctivitis. Cleanliness, moisture levels, among other factors have impact on the amount of dust mites that might possibly be found in your home.
- Pollution is commonly associated with allergic conjunctivitis. While it comes in various forms, air pollution, such as the type released from automobiles and factories, is commonly one of the more powerful types of contamination linked to allergic conjunctivitis.
- For those who suffer from allergy eyes, it is extremely important to identify the causes of allergic conjunctivitis. A person has a considerably better chance of controlling the condition and avoiding its unpleasant side effects once he or she is aware of the causes of allergic conjunctivitis.
Causes of Allergic Conjunctivitis – Allergens
- Allergens are the most common cause of allergic conjunctivitis. Allergens are triggers or instigators of allergic reactions. Allergy eyes could be caused by one or several allergens. Thus various people might possibly have to avoid more than one specific allergen in order to prevent allergy eyes. Although there are a large number of allergens, there are certain types that occur more prevalently with the condition than others.
Causes of Allergic Conjunctivitis – Allergen Types
Allergens are one of the primary causes of allergic conjunctivitis. There are a number of different types. Below are some of the more common kinds:
- Pollen – Pollen is released by trees, weeds, and grasses, and is propelled by the wind. Pollen affects those with allergic conjunctivitis by entering the throats and noses of those who are sensitive to the substance. Pollen levels are at the highest during the spring and fall months. Pollen is considered one of the hardest causes of allergic conjunctivitis to control. Some common types of pollen include, ragweed, cedar and ash.
- Mold – Another main cause of allergic conjunctivitis is mold. When inhaled, minuscule fungal spores can instigate allergy eyes. Mold usually impacts those who are susceptible between spring and late fall. Cold temperatures and snow diminish the mold spores count, yet they are still present after frost begins. Mold spores are found in leaves, hay, and grasses.
- Pets – The dander, saliva, urine, and hair from household pets are other major causes of allergic conjunctivitis. Dander are tiny scales that shed off of cats and dogs. Although it is commonly thought that the actual hairs of pets are the causes of allergic conjunctivitis, this belief is inaccurate. The hair/fur of a pet itself is not one of the causes of allergic conjunctivitis, but the hair/fur can collect dander, mold, pollen, dust, each of which cause the condition.
- Dust Mites – Dust mites are minute bugs that are one of the fundamental causes of allergic conjunctivitis. Dust mites can be found on the sofas, curtains, bed sheets, and other such places within the home. By commonly vacuuming and washing bed sheets one can reduce the number of dust mites in the home.
Causes of Allergic Conjunctivitis – Other Allergens
Beyond the causes of allergic conjunctivitis mentioned above, there are several other allergens that can cause the condition. These include:
- Air pollution
- Cigarette smoke
- Chemicals found in certain paints, carpeting