In exogenous ochronosis, the hyperpigmentation is localized to the area where the inciting agent is applied. Intradermal nevi can appear like blue nevi. Eye: Ocular manifestations are frequent in patients with ochronosis; most commonly hyperpigmentation of the sclera, primarily observed symmetrically to both sides of the cornea within the palpebral fissure. Furthermore, brown pigment spots in the limbus are generally considered pathognomonic. These ocular signs generally occur early in the development of the disease and can serve as a valuable diagnostic feature of the disease. Cartilage: Darkening and hardening of ear cartilage is a prominent feature of ochronosis. Nasal cartilage is also frequently involved. The voice can be affected by hardening of the laryngeal cartilage. Stiffening of the ribs with decreased lung function has also been reported. The intervertebral cartilage is also more prone to herniation. Connective tissue: Hardening of tendons and ligaments can predispose them to rupture. Color changes in the joints can be observed clinically. Arthropathy is common due to chronic inflammation and microruptures. Heart valves: Stenosis can results from the increased rigidity of the connective tissue as well as chronic inflammation.Symptoms of exogenous ochronosis  include:
Yellow-brown, banana-shaped fibers
Caviar-like papules
Brown-grey or blue-black hyperpigmentationMost of the lesions are seen on areas of the body that get the most sun. Causes
Exogenous ochronosis can be caused from long-term use of certain "skin-lightening" products, even if the hydroquinone is in amounts as small as 2%. Skin-lightening products are still prevalent in many parts of the world.
Gatifloxacin (brand names Gatiflo, Tequin, and Zymar) is an antibiotic of the fourth-generation fluoroquinolone family, that like other members of that family, inhibits the bacterial enzymes DNA gyrase and topoisomerase IV. It was patented in 1986 and approved for medical use in 1999. Side effects
A Canadian study published in the New England Journal of Medicine in March 2006, claimed that Tequin  can have significant side effects including dysglycemia. An editorial by
Jerry Gurwitz in the same issue called for the Food and Drug Administration (FDA) to consider giving Tequin a black box warning. This editorial followed distribution of a letter dated February 15 by Bristol-Myers Squibb to health care providers indicating action taken with the FDA to strengthen warnings for the medication. Subsequently, Bristol-Myers Squibb reported it would stop manufacture of Tequin, end sales of the drug after existing stockpiles were exhausted, and return all rights to Kyorin.By contrast, ophthalmic gatifloxacin is generally well tolerated. The observed systemic concentration of the drug following oral administration of 400 mg (0.01 ounces) gatifloxacin  is approximately 800 times higher than that of the 0.5% gatifloxacin eye drop. Given as an eye drop, gatifloxacin has very low systemic exposure. Therefore, the systemic exposures resulting from the gatifloxacin ophthalmic solution are not likely to pose any risk for systemic toxicities.