treatment because they tend to resolve spontaneously; however, resolution can take months or years. Lesions causing conjunctivitis can be treated by incising each lesion and debriding the central core. For young children, such treatment usually requires general anesthesia.

Figure 21-4 Molluscum contagiosum. A, Eyelid lesions. B, Secondary follicular conjunctivitis. (Part A courtesy of Edward L. Raab,

MD; part B courtesy of Gregg T. Lueder, MD.)

Inflammatory Disease

Blepharitis

Though less common in children than in adults, blepharitis is a common cause of chronic conjunctivitis in children. The signs and symptoms in children are similar to those in adults and include ocular irritation, morning crusting, eyelid margin erythema, and meibomian gland obstruction. Intermittent blurred vision may be present because of tear-film instability. Inferior keratitis may develop in more severe cases. Recurrent chalazia in children may indicate underlying blepharitis. Acne rosacea in children may present with chronic blepharitis and facial telangiectasias, papules, and pustules. Demodex (human mites that inhabit the hair follicles) may play a role in the pathogenesis of blepharitis.

Initial treatment of blepharitis includes warm compresses, eyelid scrubs with baby shampoo, and topical antibiotic ointment. Severe cases may benefit from either oral erythromycin or tetracycline. Erythromycin is most commonly used in young children to avoid the potential dental staining associated with use of tetracycline. Judicious use of topical steroids may be indicated in patients with corneal disease. Dietary supplementation with flaxseed oil (omega-3 fatty acid) may benefit some patients.

Jones SM, Weinstein JM, Cumberland P, et al. Visual outcome and corneal changes in children with chronic blepharokeratoconjunctivitis. Ophthalmology. 2007;114(12):2271–2280.

Ocular Allergy

Allergies are thought to affect approximately 20% of the US population, and more than 50% of

patients who seek treatment present with ocular symptoms. Allergic ocular disease is a common problem in children and is often associated with asthma, allergic rhinitis, and atopic dermatitis. Marked itching and bilateral conjunctival inflammation of a chronic, recurrent, and possibly seasonal nature are hallmarks of external ocular disease of allergic origin. Other signs and symptoms may be nonspecific and include tearing, stinging, burning, and photophobia.

Three specific types of ocular allergy are discussed in this section: seasonal allergic conjunctivitis, vernal keratoconjunctivitis (VKC), and atopic keratoconjunctivitis (AKC). All have some element of a type I hypersensitivity reaction caused by the interaction between an allergen and specific immunoglobulin E (IgE) antibodies on the surface of mast cells in the conjunctiva. This interaction initiates a cascade of biochemical events involved in mediation of the allergic response. Among the mediators released is histamine, which causes much of the itching, vasodilation, and edema that are characteristic of the ocular allergic response.

Seasonal allergic conjunctivitis

Seasonal allergic conjunctivitis is a common clinical entity that affects approximately 40 million people in the United States, including many children. It occurs in the spring and fall and is triggered by environmental contact with specific airborne allergens such as pollens from grasses, flowers, weeds, and trees. Patients typically present with red, watery eyes; boggy-appearing conjunctiva; and ocular itching. Blue-gray to purple discoloration of the lower eyelids, termed allergic shiners, can occur secondary to venous stasis from nasal congestion. Perennial allergic conjunctivitis is similar to seasonal allergic conjunctivitis and is a type I hypersensitivity reaction that occurs after contact with ubiquitous household allergens, such as dust mites and dander from domestic pets. This condition is diagnosed based on clinical presentation. Conjunctival scrapings reveal eosinophils, a finding that is almost diagnostic of an allergic response.

Treatment of all ocular allergy disorders is fundamentally similar to that of other allergy-related disorders. The most effective treatment is to remove the offending allergens from the patient’s environment. Unfortunately, attempts at removal may not be adequate to alleviate the patient’s symptoms. Medical treatment can be systemic or topical. Although oral antihistamines may be less effective at relieving specific ocular symptoms, they are often better tolerated in children, because many have an aversion to eyedrops.

Topical medications include mast-cell stabilizers, H1-receptor blockers, vasoconstrictors, corticosteroids, nonsteroidal anti-inflammatory agents, or combinations of these drugs (Table 21-2). Mast-cell stabilizers are often effective, but they must be used for a few days before an effect is seen. Nonsteroidal anti-inflammatory drops should be used with caution because associated corneal perforation has been reported. Topical steroid drops used in pulsed doses can effectively reduce severe allergic ocular symptoms, but patients must be closely monitored for adverse effects, including glaucoma and cataracts.

Table 21-2

Vernal keratoconjunctivitis

VKC is caused by type I and type IV hypersensitivity reactions. This condition most commonly affects males in the first 2 decades of life and, like seasonal allergic conjunctivitis, usually occurs in the spring and fall. It occurs in 2 forms: palpebral and limbal (or bulbar). Both types present with severe itching. The limbal form is more common in patients of African or Asian decent and is more prevalent in hotter climates.

Clinically, the palpebral form of VKC preferentially affects the tarsal conjunctiva of the upper eyelid (Fig 21-5). In the early stages, the eye may be diffusely injected, with little discharge. There may be no progression beyond this stage. However, papillae may multiply, covering the tarsal area with a mosaic of flat papules. A thick, ropy, whitish discharge may develop.