Ochronosis - An Insight

Introduction

Ochronosis is a rare skin disorder characterized by the bluish-black discoloration of the skin. The exact cause for the ochronosis is suggested to be the long-term application of the hydroquinone-containing creams. Dark-skinned people in exposure to the topical product made of phenol and resorcinol may result in ochronosis. Ochronosis can be exogenous and endogenous, and both exogenous ochronosis and endogenous ochronosis variant of ochronosis show similar signs and symptoms and features in histological findings. Several diagnostic tools are available for ochronosis, and the treatment is made to achieve the cosmesis of the patient.

What Is Ochronosis?

Ochronosis is the term derived from the Greek word ”ochre,” meaning yellow discoloration, and ochronosis was described in 1866 by Virchow. Ochronosis is a rare condition characterized as bluish-black or sometimes gray-to-blue skin discoloration. The discoloration of the skin is due to pigmentation, and it is visible in the histological findings. The dermis layer shows yellowish-brown deposits. The most commonly affected areas of ochronosis include the skin and cartilage of the ears. The sclera of the eye may also be affected by ochronosis. Ochronosis has two types, and the two types of ochronosis are mentioned below:

• Endogenous ochronosis is also referred to as alkaptonuria ochronosis.

• Exogenous ochronosis (EO).

Endogenous Ochronosis:

Endogenous ochronosis also referred to as alkaptonuria ochronosis or black urine disease, does inherit autosomal recessive disorder characterized as a genetic disorder. The accumulation of the homogentisic acid or 1,2- dihydroxy phenol acetic acid, HGA, is due to the inactivation of the enzyme called homogentisate 1,2 dioxygenase. The inactivation of the enzyme is due to the chromosome 4q23 gene. Homogentisic acid or 1,2- dihydroxy phenol acetic acid, HGA, a colorless phenolic acid, gets accumulated in the blood and undergoes polymerization. The polymerized homogentisic acid or 1,2- dihydroxy phenol acetic acid, HGA, turns into brown to black pigment, and such pigment deposits in the connective tissues. The features such as skin pigmentation, arthropathy, and cardiopathy occur due to the irreversible binding of homogentisic acid or 1,2- dihydroxy phenol acetic acid, HGA, with fibrillar collagen in the dermis layer. Homogentisic acid or 1,2- dihydroxy phenol acetic acid, HGA oxidized into benzoquinone acetate, BQA, in the urine, and due to this, the color of the urine transforms into brownish black.

Exogenous Ochronosis: Exogenous ochronosis was first described in 1906 by Pick. Exogenous ochronosis is clinically and histologically similar to endogenous ochronosis. Exogenous ochronosis is the acquired condition characterized by no systemic symptoms. The cutaneous symptoms include bluish-black macules. The critical feature of exogenous ochronosis includes “caviar-like bodies,” grayish brown macules commonly present on the malar region and the lower part of the cheeks. The temples and the neck region will also be affected by exogenous ochronosis. Topical hydrocortisone and bleaching creams used for an extended period may result in the formation of papules and nodules in exogenous ochronosis.

What Are the Causes of Ochronosis?

The exact cause of ochronosis is not clearly understood, and ochronosis is a rare skin condition. Unprotected sun exposure and long-term exposure to hydrocortisone-containing products are the etiological factors for the incidence of ochronosis. It was observed that hydroquinone at 2% can even cause ochronosis in some individuals. The various other etiologies of ochronosis are mentioned below:

• Unprotected sun exposure.

• Long-term use of hydroquinone-containing skin-lightening agents.

• Increase the number of viable melanocytes.

• Occupation outdoor.

• Widespread use of hydroquinone in the whole body.

• Applying hydroquinone in large quantities.

• Phenol or resorcinol-containing skin-lightening creams.

• The alcoholic solution contains 2 percent of hydroquinone.

• Impaired melanin production.

What Are the Symptoms of Ochronosis?

The ochronosis and its types have various symptoms. The symptoms of ochronosis are skin pigmentation. Hyperpigmentation is present in sun-exposed areas. The symptoms of ochronosis develop from six months to three years and last for an extended period. The symptoms of ochronosis are given below:

• Hyperpigmentation in the sun-exposed or photo-exposed areas.

• Grayish brown or bluish brown macules.

• Lesions are hyperchromic.

• Pinpoint lesions are speckles.

• Papules are caviar like.

The three stages of clinical features of ochronosis described by Dogliotti and Leibowitz in 1979 are mentioned below:

• Stage 1 - Erythematous called redness, hyperpigmentation is mild.

• Stage 2 - Scanty atrophy, caviar-like lesions are showing progressive hyperpigmentation pigmented colloid milium.

• Stage 3 - Sarcoid like papules or nodules are present.

According to Phillips et al., the graded system of ochronosis is mentioned below.

• Mild - dark coarse skin.

• Moderate - skin shows prominent black papules.

• Severe - caviar-like dark pimples are large and coalesce.

Hardwick et al., in 1989, based grades of ochronosis are mentioned below.

• Grade 1 - Macules show faint sooty pigmentation.

• Grade 2 - Small distinct macules.

• Grade 3 - Dark papules.

• Grade 4 - Above one-millimeter colloid milia.

• Grade 5 - Cysts are keloid-like nodules.

What Is the Diagnosis of Ochronosis?

The diagnosis is based on the history of symptoms and physical examination. The symptoms of ochronosis are similar to melasma, and the proper diagnosis is made to avoid misdiagnosis. Several diagnostic tools are available to diagnose ochronosis, and the diagnostic tools used to diagnose ochronosis are mentioned below.

• History of the patient.

• History of symptoms.

• Physical examination.

• Dermoscopy.

• Woods lamp examination.

• Ultralight photography.

• Reflectance confocal microscopy.

• Skin biopsy and histopathology is the gold-standard diagnostic tool for ochronosis.

• Histopathological findings are mentioned in the following features.

• Fibers are banana-shaped.

• Homogenization.

• Swelling of collagen bundles.

• Speckled macules.

• Caviar-like papules.

What Is the Treatment of Ochronosis?

The treatment of ochronosis is quite tricky, and various treatment modes are available. The different treatment modes available to treat ochronosis are mentioned below.

• Nonpharmacological therapy can be worn by avoiding or limiting sun exposure by using wide-brim hats, sunglasses, goggles, and sun-protective clothes.

• Topical retinoic acid.

• Glycolic acid.

• Topical corticosteroids.

• Antioxidants such as vitamin E and vitamin C.

• Chemical peeling using tricarboxylic acids or glycolic acids.

• Dermabrasion.

• Carbon dioxide laser treatment.

Conclusion

Ochronosis is a rare skin disorder characterized by bluish-black or grayish-blue pigmentation caused due to the long-term application of hydroquinone-containing skin lighteners or bleaching creams followed by long-term unprotected sun exposure. The symptoms include papules and macules on sun exposure, which affect the skin, eye sclera, and ear cartilage. Sun protective measures are followed, and hydroquinone-containing products are avoided to avoid ochronosis. Ochronosis is two types, and both show similar clinical and histological features. The confirmed diagnosis is made by skin biopsy, and the treatment is planned accordingly.