Dating eye contact
Reactive arthritis is highly associated with HLA-B27.
The symptoms are due to release of histamine and other active substances by mast cells, which stimulate dilation of blood vessels, irritate nerve endings, and increase secretion of tears.Irritant or toxic conjunctivitis show primarily marked redness.If due to splash injury, it is often present in only the lower conjunctival sac.Bacterial infections, allergies, other irritants, and dryness are also common causes.Both bacterial and viral infections are contagious and passed from person to person, but can also spread through contaminated objects or water.The infection usually begins with one eye, but may spread easily to the other.
Viral conjunctivitis shows a fine, diffuse pinkness of the conjunctiva, which is easily mistaken for the ciliary infection of iris (iritis), but there are usually corroborative signs on microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), swelling of the conjunctiva, itching, and increased lacrimation (production of tears).
Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and mucopurulent discharge.
Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days.
Conjunctival scrapes for cytology can be useful in detecting chlamydial and fungal infections, allergy, and dysplasia, but are rarely done because of the cost and the general lack of laboratory staff experienced in handling ocular specimens.
Conjunctival incisional biopsy is occasionally done when granulomatous diseases (e.g., sarcoidosis) or dysplasia are suspected.
Though very rare, hyperacute cases are usually caused by Neisseria gonorrhoeae or N. Chronic cases of bacterial conjunctivitis are those lasting longer than 3 weeks, and are typically caused by Staphylococcus aureus, Moraxella lacunata, or gram-negative enteric flora.