Thread: Atopic keratoconjunctivitis (AKC)

Atopic keratoconjunctivitis (AKC)

Atopic keratoconjunctivitis (AKC) is a relatively uncommon but potentially blinding ocular condition. In 1952, Hogan described AKC as a bilateral conjunctivitis occurring in 5 male patients with atopic dermatitis. Originally described to flare with worsening dermatitis, Foster et al noted that some patients' ocular involvement evolves independent of dermatitis.

AKC is associated with a 95% prevalence of concomitant eczema and an 87% prevalence of asthma. Other than AKC, common ocular atopic phenomena include allergic conjunctivitis, giant papillary conjunctivitis, and vernal keratoconjunctivitis.

Pathophysiology

Atopy refers to hypersensitivity in patients with familial histories of allergic disease. Individuals with atopy often have environmental allergies, allergic asthma, rhinitis, and atopic dermatitis or eczema. Less commonly, they exhibit food allergies, urticaria, and nonhereditary angioedema. Immunoglobulin E (IgE) is the serum mediator of the exuberant responses.

Hypersensitivity reactions associated with types I and IV contribute to the inflammatory changes of the conjunctiva and the cornea that are found in AKC. During exacerbations, patients have increased tear and serum IgE levels and increased numbers of circulating B cells; T-cell levels are depressed.

Clinical
History

Look for the following in past medical history:

• Chronic or chronically relapsing atopic disease
o Dermatitis
o Asthma
o Rhinitis
• Ocular symptoms with little or no seasonal variation (as opposed to vernal conjunctivitis that is seen only in warm weather)
o Itching
o Tearing
o Ropy discharge
o Burning
o Photophobia
o Decreased vision

Physical

•Periorbita - Dennie-Morgan folds (linear lid folds secondary to chronic eye rubbing) and Hertoghe sign (absence of lateral eyebrows)

•Lids - Thickening and tylosis, crusting, edema, fissures, ptosis, and staphylococcal blepharitis

•Conjunctiva
-----◦Small- or medium-sized papillae, hyperemia, edema, excessive mucin, and limbal Trantas dots (clusters of necrotic eosinophils, neutrophils, and epithelial cells)
-----◦Formation of keratinization, cicatrization, and symblepharon in advanced disease

•Cornea-----◦Punctate epitheliopathy and keratitis, persistent epithelial defects, shield-shaped ulcers, anterior stromal scarring, and micropannus
-----◦Extensive peripheral corneal vascularization in later stages
-----◦Higher incidence of keratoconus (16%) and recurrent herpes simplex keratitis associated with AKC

•Lens - Posterior or anterior subcapsular shield-shaped cataracts

•Fundus - Degenerative vitreous changes and retinal detachment

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