Conjunctivitis etiology

General absence of conjunctivitis, hoarseness, cough, rhinorrhea, discrete ulcerations, and diarrhea (suggestive of viral etiology)... 

Extensive studies have been done on a clearly defined asthma syndrome produced by exposure to western red cedar. ° Plicatic acid has been identified as the etiologic agent. The western red cedar asthma syndrome includes rhinitis, conjunctivitis, wheezing, cough, and nocturnal attacks of breathlessness characterized by a precipitous decline in FEVi. There is no apparent relation between skin sensitivity and respiratory changes. No precipitating IgG antibodies are found in the serum of sensitized individuals, and circulating IgE antibodies are present in about one-third of affected individuals. 

Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by the deposition of noncaseating granulomas surroimded by lymphocytes. The infiltrative optic neuropathy in sarcoidosis may be the first and only ocular sign or may occur in conjunction with other ocular manifestations of sarcoidosis such as uveitis, candle-wax drippings (exudates around the retinal vessels), and choroidal granulomas. Optic disc edema... 

The differential diagnosis of conjunctivitis can sometimes be challenging. Laboratory testing can help both to identify the etiology and to effectively direct treatment. Ideally, in all cases of infectious conjimctivitis, cultures or ocular smears should be obtained to determine the exact etiology. However, in practice this rarely is done. Experienced practitioners typically treat infectious conjimctivitis empirically. In most cases eye care providers can diagnose conjunctivitis accurately and treat it effectively... 

Condition Age Conjunctivitis Cornea Associated Findings Etiologic Agent... 

Examination typically reveals diffuse SPK erosions and also may disclose punctate epithelial keratopathy that is visible as small grayish opacities in the epithelium. The location and pattern of this keratitis can be helpful in determining the etiology (Box 26-1) and in distinguishing the condition from bacterial-related causes. SPK from blepharitis usually is more severe in the inferior one-third of the cornea where it contacts the staphylococcal exotoxins from infection of the lower lid. In cases of SPK caused by bacterial conjunctivitis, the entire cornea may be involved. 

The urinary excretion data of uric acid and oxypurine in conjunction with the extremely low serum urate speak strongly for this. However, we have not measured the xanthine oxidase levels in the tissue of these patients leaving some small measure of doubt as to the true etiology of these deranged values. 

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