Eye Signs of Systemic Disease: Case 3 Presumed Ocular Histoplasmosis Syndrome

Long-standing chorioretinal scarring in both eyes didnot affect a 67-year-old woman's vision. The scars wereroundish, irregular, and yellowish white with interior pigmentation(A and B). This patient had presumed ocular histoplasmosissyndrome (POHS), a common disorder in regions such asthe Mississippi, Ohio, and Missouri river valleys, wherethe fungus Histoplasma capsulatum is endemic. Inhaledspores of the culprit organism cause granulomas in thelungs, liver, spleen, and the choroid of the eye. Unless themacula is involved, the patient's vision is unaffected. Typicalfindings in infected patients include:

• Punched-out "histo" spots that can be seen throughoutthe retina (A and B).
• Peripapillary--diffuse, circumferential choroidal--atrophythat extends beyond the disc margin (C, in a differentpatient).
• Linear streaks of chorioretinal atrophy seen in theperiphery.
• Choroidal neovascularization, which may be characterizedby serous detachment of the retina, subretinal hemorrhage,and hard lipid exudate. In most patients, thechoroidal neovascularization occurs at the edge of an oldhealed chorioretinal scar.
• Absence of vitritis or iritis.
• Positive skin tests for Histoplasma. This is a commonfinding in most patients with POHS. Refer those with activelesions to an infectious disease specialist.
• HLA markers B7, DR2, and DQ1, which may geneticallypredispose persons to POHS.

Macular involvement results in impaired vision. Lasertreatment of macular lesions is ineffective; however, activelesions outside the macula may be treated with laser photocoagulation.Treatment of inactive lesions is not advisedbecause it may stimulate subretinal neovascularization.Because this patient's lesions were inactive, notherapy was warranted. Annual eye examinations wererecommended.