Dictionary of Allergies .. Staphylococcal blepharo-keratoconjuctivitis

Staphylococcal blepharo-keratoconjuctivitis, (BKC), .

BKC is an example of immune complex disease in the eye. This can be seen in children who have marginal blepharitis, or inflammation of the margins of the eyelids. They show also a mixed papillary and follicular conjunctivitis, and more important they have a superficial keratitis with vascularisation, which by its very nature is sight threatening [2].

Staphylococci represent an important source of external infections of the eye. In addition to acute staphylococcal conjunctivitis a spectrum of subacute or chronic disease may be found. According to Valenton und Okumoto, with this staphylococci-associated blepharo-kerato-conjunctivitis in culture-positive cases S. aureus is found in 31% and S. epidermidis in 69% of smears. Microbiallergic and toxic mechanisms are the underlying etiology. The blepharitis may be squamous or ulcerative. The underlying cause is a dermal irritation by staphylococcal toxins [1].

As early as 1937, Thygeson and Allan postulated a toxin-induced skin irritation by a "dermonecrotic factor." In chronic cases a papillary conjunctivitis caused by a toxin reaction can be observed. Histologically, no lymph follicles or eosinophils are present. Several types of keratitis and corneal involvement are found. An epithelial keratitis is caused by toxic mechanisms. Marginal infiltrates and ulcers indicate an antigen-antibody reaction. Phlyctenulae indicate a delayed immune reaction (Gell and Coombs type IV).

Complications include vascular pannus, corneal scarring, and rarely corneal melting and ulcers. Therapy depends on the severity of the inflammation and the underlying pathomechanism. This includes reduction of toxin-producing organisms by hygiene of the lid margins and application of topical disinfectants and antibiotics. With immunological phenomena topical steroids are required [1].

Local antistaphylococcal antibiotics have limited effect. Systemic administration of erythromycin suspension for a long time produces a resolution of the condition, but recurrences may follow when the medication is stopped [2].

References

Buckley, R.J.: Occular Allergic Disease. In Highlights in Allergy and Clinical Immunology ed. by B. Wuthrich. Hogrefe and Huber, p. 224, 1992. Tetz MR, Klein U, Völcker HE. Staphylococcus-associated blepharokeratoconjunctivitis. Clinical findings, pathogenesis and therapy.Ophthalmologe. 1997 Mar;94(3):186-90.