Clinical Approach to Linear Hyperpigmentation: A Review Article

Abstract

Linear hyperpigmentation is an unusual anatomical configuration in clinical dermatology. Owing to its rarity, consensus on the most effective method of classification is lacking. While linear hyperpigmentation generally follows Blaschko's lines, this is not universal. Clinical findings such as adherence to Blaschko's lines, associated morphological findings (including other cutaneous lesions), and systemic manifestations can be used to further characterize and diagnose variants of the disorder. Early detection of any underlying disease is vital, especially in cases with effective management, because the disorder may make it difficult to manage hyperpigmentation. Herein, we introduce a logical clinical diagnostic approach that represents a useful tool for dermatologists to efficiently evaluate patients presenting with linear hyperpigmentation. A simplified systematic and evidence-based approach is useful for this clinical condition owing to the heterogeneous causes and lack of specific diagnostic tools.

Keywords: Blaschko’s lines; approach; blaschkitis; hyperpigmentation; linear; pigmentary mosaicism.

Figure 1

Clinical approach for linear hyperpigmentation.

Figure 2

Cutaneous clues associated with linear hyperpigmentation.

Figure 3

Blaschkoid lichen planus. Hyperpigmented macules and patches arranged in a linear pattern following Blaschko’s lines over the arm and extending to the upper chest.

Figure 4

Linear morphea (limb variant). A unilateral linear band of sclerotic, atrophic, and hyperpigmented plaques affecting the left forearm of an eight years old boy.