Ochronosis is the syndrome which is caused due to accumulation of homogentisic acid in the connective tissues. The affected tissues appear bluish grey because of a light scattering phenomenon. This condition is often associated with alkaptonuriua but can also occur due to exogenous administration of phenol complexes like hydroquinone. Ochronosis can also be caused due to long term usage of certain skin lightening products even if it contains only 2% hydroquinone.
Ochronosis occurs due to deposition of phenols as plaques in the matrix of cartilage. The pigments can also get incorporated into elastin fibers and collagen. When the pigment gets in the skin it changes the structure of the fibers causing enlargement and curling. The embedded pigments can also cross link with pigment depositions in the adjacent fibers thus stabilizing or reducing the elastic recoil of the fibers. This causes hardening of elastic structures thus increasing their rigidity and brittleness. When it gets ruptured, the exposed pigments can cause a foreign body reaction or inflammation. This can cause darkly pigmented sweat and breast milk.
Last date updated on December, 2020