<unk>  (con·junc·ti·vi·tis) is an inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids), most commonly due to an allergic reaction or an infection (usually bacterial or viral).<unk>  may be classified based on the duration of symptoms into hyperacute, acute, or chronic.
Additionally, based on the causality of the inflammation and age group,<unk>  may be classified into infective<unk>  (bacterial and viral), neonatal<unk>  (ophthalmia neonatorum), allergic<unk> , keratoconjunctivitis sicca (dry eye syndrome), and superior limbic keratoconjunctivitis (SLK). 
Common causes of<unk>  include bacteria, viruses, and environmental factors.
Viral<unk>  is the most common cause of infectious<unk>  both overall and in the adult population. Between 65% and 90% of cases of viral<unk>  are caused by adenoviruses. Bacterial<unk>  is the second most common cause. 
Allergic<unk>  is the most frequent cause, affecting 15% to 40% of the population.
Noninfectious<unk>  includes keratoconjunctivitis sicca (dry eye syndrome) and superior limbic keratoconjunctivitis, which may caused by inflammation secondary to immune-mediated diseases.
Prognosis for<unk>  usually good with treatment. Infective<unk>  resolves, in 65% of cases, within 2-5 days.
Complete history will help determine the correct therapy.
The symptoms of<unk>  differ based on the cause of the inflammation. Common symptoms to all forms of<unk>  include redness, excessive tearing, and irritation. Photophobia, itching, mucopurulent or non-purulent discharge, chemosis, burning eyes, blurred vision, and eyelid swelling are variable.
Physical examination of patients with<unk>  is usually remarkable for conjunctival injections, epiphora, hyperemia, chemosis, and muco-purulent or watery discharge. However, ophthalmologic examination may be varies based on<unk>  subtypes.
Laboratory tests are not often required in patients with mild<unk> . Conjunctival cultures are generally reserved for<unk>  presenting with severe purulent discharge, and cases suspicious for gonococcal or chlamydial infection. 
Allergic<unk>  may be treated with artificial tears and topical antihistamines, vasoconstrictive agents, mast cell stabilizers, NSAIDs, and corticosteroids. Cool compresses are recommended to reduce eyelid and periorbital edema. Topical antimicrobial therapy is only recommended for patients with either bacterial or herpetic<unk> , but not allergic or adenoviral<unk> . Systemic antibiotic therapy is necessary to treat<unk>  due to Neisseria gonorrhoeae and Chlamydia trachomatis.
Conjunctivitis
Eyelash
Laryngitis
Pharyngitis
Sinusitis  
Sinusitis
Cerebritis
Rhinitis