Figure 21-5 Palpebral vernal keratoconjunctivitis, upper eyelid. (Courtesy of Ken K. Nischal, MD.)

The limbal form of VKC presents early with thickening and opacification of the conjunctiva at the limbus, usually most marked at the upper margin of the cornea. The discrete limbal nodules that appear are gray, jelly-like, elevated lumps with vascular cores. A whitish center may appear in the raised lesion filled with eosinophils and epithelioid cells. This complex is called a Horner-Trantas dot. Limbal nodules may increase in number and become confluent. They persist as long as the seasonal exacerbation of the disease lasts.

The cornea may become involved with punctate epithelial erosions, especially superiorly. Corneal involvement may progress to a large confluent area of epithelial defect, typically in the upper half of the cornea, called a shield ulcer. The ulcer is sterile and clinically resembles an ovoid corneal abrasion.

Treatment of VKC is usually less effective than that of seasonal allergic conjunctivitis. Eyedrops combining a mast-cell stabilizer and an H1-receptor blocker may be used initially. Severe cases may require topical steroids or topical cyclosporine. Supratarsal injection of corticosteroids may be used in patients with refractory palpebral VKC.

Atopic keratoconjunctivitis

AKC is a nonseasonal disorder that occurs in patients with atopic disease. It is relatively rare in children. See BCSC Section 8, External Disease and Cornea, for further discussion.

Ligneous Conjunctivitis

Ligneous conjunctivitis is a rare bilateral chronic disorder characterized by firm, “woody,” yellowish, fibrinous pseudomembranes on the palpebral conjunctiva. It is thought to be secondary to severe deficiency in type I plasminogen. No single treatment is consistently effective. Surgical removal, amniotic membrane transplantation, fresh frozen plasma, and heparin have been used.

Miscellaneous Conjunctival Disorders

Papillomas

Papillomas are benign epithelial proliferations that usually appear as sessile masses at the limbus or as pedunculated lesions of the caruncle, fornix, or palpebral conjunctiva. They may be transparent, pale yellow, or salmon colored. They are sometimes speckled with red dots. Papillomas in children usually result from viral infection. They often resolve spontaneously. Surgical excision is indicated if there is persistent associated conjunctivitis or keratitis or if new lesions continue to appear. Recurrence following surgical excision is possible. Oral cimetidine can induce papilloma regression.

Conjunctival Epithelial Inclusion Cysts

Conjunctival inclusion cysts are clear, fluid-filled cysts on the conjunctiva. These cysts are often seen in patients who had ocular surgery or trauma. Excision is indicated if the cysts cause irritation.

Conjunctival Nevi

Conjunctival nevi are relatively common in childhood. The lesions may be flat or elevated. Histologically, most of these nevi are compound (nevus cells found in both epithelium and substantia propria); others are junctional (nevus cells confined to the interface between epithelium and substantia propria). Nevi are typically brown, but approximately one-third are nonpigmented and

have a pinkish appearance. The lesions are occasionally noted at birth; more commonly, they develop during later childhood or adolescence (Fig 21-6). Removal may be indicated if significant growth occurs, although transformation to malignant melanoma is extremely rare in childhood.

Figure 21-6 Pigmented nevus of the bulbar conjunctiva, right eye, recently developed in a 4-year-old girl.

Ocular Melanocytosis

Ocular melanocytosis (melanosis oculi) is a congenital abnormality characterized by unilateral patchy but extensive slate-gray or bluish discoloration of the sclera (Fig 21-7). Intraocular pigmentation is also increased, which is associated with a higher incidence of glaucoma and risk of malignant melanoma. Some patients, particularly persons of Asian ancestry, may have associated involvement of eyelid and adjacent skin with dermal hyperpigmentation that produces brown, bluish, or black discoloration without thickening (oculodermal melanocytosis, nevus of Ota). Small patches of slategray scleral pigmentation, typically bilateral and without clinical significance, are common in black and Asian children. Melanosis of skin and sclera is occasionally associated with Sturge-Weber syndrome and Klippel-Trénaunay-Weber syndrome.

Figure 21-7 Congenital ocular melanocytosis.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, life-threatening conditions that represent different intensities of an acute inflammatory systemic disease affecting skin and mucous membranes. In the pediatric population, the male to female ratio is 2:1. The mortality rate in the pediatric population, at 1%, is much lower than that of adults, although the morbidity is 45% and the recurrence rate is 18%. The most common etiologies of SJS and TEN in children are medications (usually anticonvulsants and sulfonamides) and infections (usually Mycoplasma species or herpes simplex virus). The pathogenesis of SJS and TEN is unknown.

Systemic manifestations range from mild to severe. A prodrome of fever, malaise, and upper respiratory tract infection is followed by bullous mucosal and skin lesions. These lesions rupture, ulcerate, and become covered by gray-white membranes and a hemorrhagic crust.

Ocular involvement, which occurs in as many as 50% of patients, varies from mild mucopurulent conjunctivitis to severe perforating corneal ulcers. Ocular involvement in SJS and TEN begins with edema, erythema, and crusting of the eyelids. The palpebral conjunctiva becomes hyperemic, and distinct vesicles or bullae may occur. In many instances, epithelial defects or ulcers involving the tarsus and fornices develop. In severe cases, membranous or pseudomembranous conjunctivitis may