Diagnostic Features and Differentiational Diagnosis of Melasma

Diagnostic Features and Differential Diagnosis of Melasma

Accurate diagnosis of melasma requires careful evaluation of characteristic clinical features, as facial hyperpigmentation encompasses various conditions with different therapeutic implications. Key diagnostic criteria include the specific anatomical distribution pattern of patchy brown pigmentation, absence of scaling, and notably, the tendency to spare the periorbital area including upper and lower eyelids. Wood lamp examination can provide additional diagnostic information by helping differentiate between superficial and deep melasma, though this distinction may not always be definitive.

The differential diagnosis of facial hyperpigmentation is broad and requires systematic evaluation to distinguish melasma from other pigmentary disorders. Postinflammatory hyperpigmentation secondary to acne, drug-induced hyperpigmentation, and photodamage including solar lentigines and seborrheic keratoses must be considered. Additionally, dermatosis papulosa nigra and hyperpigmentation associated with metabolic conditions should be evaluated. Each condition may require different therapeutic approaches, making accurate diagnosis essential for treatment success.

Melasma can present as epidermal, dermal, or mixed variants, with dermal involvement being more challenging to treat due to deeper pigment deposition. While Wood lamp examination can assist in determining the depth of pigmentation, mixed presentations are common and may require treatment approaches that address multiple levels. Dermoscopy is gaining recognition as a valuable diagnostic tool, particularly for appreciating subtle erythematous changes and vascularity that may not be apparent on routine clinical examination, though additional training may be needed for optimal utilization in pigmentary disorders.