Ochronosis exogenous acquired E70.2

Pick, 19o3 (Arch Derm Syph 1903: 160)

Exogenously induced (cosmetic) ochronosis variant (exogenous dyschromia) caused by bleaching agents, which occurs particularly frequently in dark-skinned ethnic groups. The clinical picture is mainly observed after >3 months of prolonged use of hydroquinone-containing bleaching agents in concentrations of > 4 %.

Ochronosis was most frequently detected in middle-aged women (53.2 %), women of African descent (45.2 %), black ethnicity (55.5 %) and Fitzpatrick skin types V-VI (52.4 %) (Ishack S et al. 2022).

In Europe, external ochronosis is a rare finding.

For South Africa, a prevalence of 28-35% is reported in the dark-skinned population.

A connection with bleaching agents containing hydroquinone can be assumed! It is postulated that the hydroquinone contained in bleaching creams, a pehnol derivative, blocks the tissue-resistant homogentisic acid oxidase. This leads to an accumulation and deposition of homogentisic acid polymers.

In a larger cross-sectional study (n=126), topical preparations with hydroquinone concentrations of > 4 % were used most frequently (32.5 or 35.7 % of cases). The median duration of use was 5 years, with only a few cases reported with a duration of use of 3 months or less and only eight cases with a duration of use of 1 year or less (Ishack S et al. 2022).

Other risk factors for the manifestation of the disease are skin type V/VI, UV exposure and ethnic characteristics (long-term bleaching is a cultural phenomenon of certain ethnic groups for whom a lighter complexion is a desirable ideal of beauty).

The long-term use of bleaching substances in dark-skinned African women is reported to be 25-96%.

Face with emphasis on the zygomatic arches and areas particularly exposed to UV radiation.

Asymptomatic, extensive, confluent, irregular, brown to slate gray hyperpigmentation, sometimes with underlying erythema. The changes are particularly prominent over bony prominences (forehead, nose, zygomatic bones).

Greyish-basophilic tinged fine feathery collagenous fibres grouped in the upper dermis. In the papillary body slightly clumped yellowish-brownish, banana-shaped, "ochronotic" fibres. Isolated macrophages.

The disease is to be distinguished from the extremely rare autosomal recessive endogenous ochronosis (alkaptonuria) with defect of the homogentisic acid oxidase.

Avoidance of bleaching agents containing hydroquinone. Consistent light protection.

Case reports on successful therapy approaches with tretinoin, trichloroacetic acid and cryotherapy are available.

Furthermore, the successful use of various bleaching agents has been reported. Laser systems CO2-, ruby, alexandrite-, Nd-YAG-laser reports possibly in combination with dermabrasion.

Exogenous ochronosis has been documented in the literature since 1903. The cases described at that time were due to the long-term use of "carbolic acid", a common name for phenol at the time, which often led to "carbolic acid poisoning". Phenol was widely used in various concentrations as a caustic and disinfectant. The risk of absorption is immense. Even 20g applied externally can lead to severe poisoning.

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4. Blumeyer A et al. (2016) Progressive hyperpigmentation of the face. Dermatologist 67: 922-924

5. Haas N et al. (1988) Ochronosis-like pigmentation after hydroquinone-containing bleaching cream in a black African woman. Act Dermatol 14: 173-176

6. Ishack S et al. (2022) Exogenous ochronosis associated with hydroquinone: a systematic review. Int J Dermatol 61:675-684.

7. Pick L (1906) On ochronosis. Berl Klin Wochenschrift 43: 478-480
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