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Acute Conjunctivitis 

Conjunctivitis is defined as inflammation of the conjunctiva; it is usually caused by infection or allergy. It is often referred to as "pink eye." conjunctivitis, red eye and pink eye, blood shot eyes.

Neonatal conjunctivitis occurs in 1.6-12% of newborns. The most common cause is chemical irritation from antimicrobial prophylaxis against bacterial infection, followed by Chlamydia trachomatis infection. Haemophilus influenzae and Streptococcus pneumoniae may also cause infection.

Rarely, gram-negative organisms such as Escherichia coli, Klebsiella, or Pseudomonas sp can cause neonatal conjunctivitis. Neisseria gonorrhoeae is an unusual cause of neonatal conjunctivitis.

Herpes simplex can cause neonatal keratoconjunctivitis; however, it is almost always associated with infection of the skin and mucous membranes, or with disseminated disease. The presence of vesicles anywhere on the body in association with neonatal conjunctivitis is suggestive of herpes.

In older infants and children, H influenzae is by far the most common identifiable cause of conjunctivitis, causing 40-50% of episodes. S pneumoniae accounts for 10% of cases, and Moraxella catarrhalis is the third most common cause. Chlamydia trachomatis can cause conjunctivitis.

Adenovirus is the most important viral cause of acute conjunctivitis. This organism often causes epidemics of acute conjunctivitis. It causes 20% of childhood conjunctivitis.

Diagnosis

Neonates

In cases of neonatal conjunctivitis, a Gram stain and culture should be obtained to exclude N gonorrhoeae conjunctivitis.

Chlamydia trachomatis antigen detection assays have a sensitivity and specificity of 90% or better.

Infants and older children. Outside the neonatal period, a Gram stain is usually not needed unless the conjunctivitis lasts longer than 7 days. The presence of vesicles or superficial corneal ulcerations suggests herpetic keratoconjunctivitis.

Differential diagnosis of conjunctivitis

Systemic diseases. Most cases of red eye in children are caused by acute conjunctivitis, allergy, or trauma; however, Kawasaki disease, Lyme disease, leptospirosis, juvenile rheumatoid arthritis, and Stevens_Johnson syndrome may cause conjunctivitis. Glaucoma is a significant cause of a red eye in adults; however, it is rare in children.

Allergic conjunctivitis

Allergic eye disease is characterized by pronounced ocular itching, redness, tearing, and photophobia. This recurrent disease has seasonal exacerbations in the spring, summer, and fall. Children who have allergic conjunctivitis often have other atopic diseases (rhinitis, eczema, asthma) and a positive family history. Allergic conjunctivitis is characterized by mild swelling and injection of the conjunctiva.

Treatment

Topical decongestants: Naphazoline 0.1% ( Naphcon), phenylephrine ( Neo-Synephrine), and oxymetazoline ( OcuClear, Visine LR) may be used qid, alone or in combination with ophthalmic antihistamines such as antazoline ( Vasocon-A) or pheniramine maleate ( Naph-Con-A).

Topical lodoxamide ( Alomide) 0.1% ophthalmic solution, 1-2 drops qid, is helpful in more severe cases.

Topical corticosteroids are helpful, but long_term use is not recommended; dexamethasone ( Decadron) 1-2 drops tid-qid; TobraDex ( tobramycin/dexamethasone 1-2 drops tid-qid.

Treatment of acute infectious conjunctivitis

Gonococcal ophthalmia neonatorum is treated with ceftriaxone (50 mg/kg/day IV/IM q24h) or cefotaxime (100 mg/kg/day IV/IM q12h) for 7 days.

Neonatal conjunctivitis caused by C trachomatis is treated with erythromycin , 50 mg/kg/day PO divided in 4 doses for 14 days.

Bacterial conjunctivitis among older infants and children is treated with polymyxin-bacitracin ( Polysporin) ointment, applied to affected eye tid.