Differential diagnosis and management of hyperpigmentation

There is an increasing recognition of ethnic dermatology to reflect the increase in skin of colour (SOC) populations in the UK. Hyperpigmentary disorder is one of the commonest skin concerns in SOC but there has been limited training available in this field of dermatology. Variations in skin colour are genetically determined by the amount of melanin content, the eumelanin/pheomelanin ratio and the size of melanosomes, but is also influenced by other factors such as hormones and extrinsic factors such as ultraviolet radiation. Hyperpigmentation is a broad term to describe increased pigmentation in the skin, and making a correct diagnosis is an important first step in the successful management of hyperpigmentary disorders. A systematic approach based on the disease pathogenesis (e.g. reactive vs. nonreactive, increased melanin vs. increased number of cells or epidermal vs. dermal pigmentation) aided by a detailed history and clinical examination is the best way to diagnose a hyperpigmentary disorder. Based on its pathogenesis, management can be planned. For epidermal hyperpigmentation caused by increased melanin, topical skin-lightening agents targeting inhibition of tyrosinase or melanosome transfer and promotion of keratinocyte turnover can be used. Hydroquinone-containing cream is the gold-standard treatment for epidermal hyperpigmentation. Alternative treatments include laser toning or chemical peels. However, increased dermal pigmentation is more challenging to target with topical treatments. If hyperpigmentation is due to increased numbers of melanocytes or keratinocytes, high-fluence laser is the most appropriate treatment method.