About ochronosis

What is ochronosis?

Alkaptonuria is a rare genetic metabolic disorder characterized by the accumulation of homogentisic acid in the body. Affected individuals lack enough functional levels of an enzyme required to breakdown homogentisic acid. Affected individuals may have dark urine or urine that turns when exposed to air. However, this change may not occur for several hours after urination and often goes unnoticed. Aside from dark urine that is present from infancy, affected individuals generally do not develop symptoms (asymptomatic) during infancy or childhood and often remain unaware of their condition until adulthood. Affected individuals eventually develop ochronosis, which is the bluish- discoloration of connective and other tissue within the body. Affected individuals may develop discoloration of the skin overlying cartilage within the body such as over part of the outer ear. In some cases, the whites of the eyes (sclera) may also become discolored. In adulthood, affected individuals also develop progressive arthritis of the spine and large joints. The HDG gene codes for the enzyme required for the breakdown of homogentisic acid. Mutations in HDG cause alkaptonuria.

What are the symptoms for ochronosis?

Dark urine symptom was found in the ochronosis condition

Ochronosis is the bluish- or grey-blue discoloration of the skin, especially the ear cartilage, the ocular (eye) tissue, and other body locations. The affected tissue becomes weak and brittle with time, leading to chronic inflammation, joint pain, and osteoarthritis.

What are the causes for ochronosis?

Alkaptonuria is inherited in an autosomal recessive manner. Alkaptonuria can be diagnosed based on the symptoms, laboratory testing, and genetic testing. When Ochronosis is due to exposure to substances (called exogenous Ochronosis), the condition is not inherited. 

What are the treatments for ochronosis?

Ochronosis is a type of condition triggered by malarial drugs, skin-lightening creams, and over-exposure to the sun. These are very difficult conditions for treatment and the results are unpredictable and inconsistent.

These are various ways for treatments are as follows:

  • Nonpharmacological measures: Sun protective clothes, goggles, and hats are important. Uses of offending agents must be stopped, and sun protection is useful for further progress.
  • Pharmacological treatments: chemical sunscreens and physical sun blocking widely help with this treatment.
  • Topical retinoid acid, glycolic acid, and a topical corticosteroid (low-potency creams) are widely used for improvement in pigmentation,
  • Antioxidants, high doses of Vitamin E and C are useful because these vitamins are very useful in dilatation of pigmentation and act as de-pigmentating agents.
  • Procedural treatments: glycolic acid or tricarboxylic acid has been used for the treatment of chemical peeling that shows improvement in pigmentation.

Blue-grey discoloration of skin,Black urine,Sunsenstive skin
Dark discoloration of skin,Alkaptonuria,Sunsensitive skin,Hyperchromic,Pinpoint, and caviar-like papules
Sunscreen,Topical retinoic acids,Glycolic acid and antioxidants like vitamin C and E

What are the risk factors for ochronosis?

Exogenous Ochronosis is associated with malarial drugs, skin-lightening creams and over-exposure to the sun. Other than the skin findings, there are no other health affects.

Is there a cure/medications for ochronosis?

Ochronosis is a rare disorder characterized by a clinical appearance of blue- or grey-blue pigmentation, which reflects the histological finding of yellow-brown deposits in the dermis. It most commonly affects the skin and sometimes the cartilages of ears and sclera of eyes.
There are two types of ochronosis:
Endogenous or alkaptonuric ochronosis
Exogenous ochronosis (EO).

There are various modalities available for treatment as follows.
Nonpharmacological measures

  • The most important step is to prevent the major risk factor, which is sun exposure. Use of chemical sunscreen, that is benzoate free, is needed.
  • Physical sunscreen in the form of Wide-brim hats, sun-goggles and appropriate sun-protective clothing is equally important.

Pharmacological treatments.

  • Physical sunblocks and chemical sunscreens widely help in clinical improvement of the skin lesions of EO, especially when combined with the other pharmacological and procedural approaches.
  • Topical retinoic acid, glycolic acid, and a topical corticosteroid which are low-potency creams used judiciously, often lead to considerable improvement in pigmentation.
  • Studies show the efficacy of tetracycline in the clearance of papular sarcoid-like ochronosis.
  • Antioxidants, high doses of Vitamin E and C, may assist in the dilution of the pigment. Both Vitamin C and Vitamin E act as de-pigmentating agents. Both act synergistically along with antioxidants to provide photoprotection.

Video related to ochronosis