Ochronosis - External and Internal Eye
Symptoms and signs do not generally appear until adulthood, although the urine discoloration is usually noted in infancy.
Exogenous ochronosis mimics alkaptonuria and can occur from exposure to several drugs and chemicals (eg, topical phenols, hydroquinone, or carbolic acid and ingestion of antimalarials).
For more information on alkaptonuria, see OMIM.
E70.29 – Other disorders of tyrosine metabolism
360381004 – Alkaptonuria
- The discoloration of exogenous ochronosis is identical, but no homogentisic acid is demonstrable in urine and arthropathy is absent.
- Nevus of Ota
- Addison's disease
- Melasma is characterized by tan or brown pigmented patches distributed bilaterally over the malar cheeks, temples, and forehead.
- Blue nevus may have similar blue-grey pigmentation but is a smaller well-demarcated macule or papule.
- Melanoma can manifest with disseminated melanosis, but pigmentation will usually be less well demarcated and will present later in life.
- Lentigos or giant café au lait macules impart a tan to brown hue.
- Lentigo maligna
- Lentigo maligna melanoma
- Drug-induced pigmentation can either be diffuse or photodistributed.
- Ecchymoses will have a history of trauma.
- Arteriovenous malformations can range from blue to red.