Can pibaldism present as hyperpigmented linear lesions at the forehead, varying from erythematous to hypo and hyperpigmentation?

Piebaldism Presentation: Forehead Linear Hyperpigmented Lesions

Piebaldism does not typically present with hyperpigmented linear lesions on the forehead that vary between erythematous, hypo- and hyperpigmentation. Piebaldism has a distinct clinical presentation that differs from the described manifestation.

Characteristic Features of Piebaldism

Piebaldism is an autosomal dominant disorder characterized by:

• Congenital absence of melanocytes in affected skin and hair areas 1
• White forelock (poliosis) as the most recognizable feature 2
• Stable, well-demarcated white patches (leukoderma) present from birth 3
• Hyperpigmented macules within or at the borders of depigmented areas 4
• Typically affecting the forehead, ventral trunk, and extremities in a symmetrical pattern 5
• Caused by mutations in the KIT proto-oncogene affecting melanoblast migration and development 6

Differentiating Piebaldism from Other Conditions

The presentation described in the question with linear hyperpigmented lesions on the forehead showing erythema and varying pigmentation is not consistent with piebaldism. Instead, consider these differential diagnoses:

1. Lichen sclerosus: Can present with hyperpigmented areas, erythema, and varying pigmentation 1. Typically affects genital areas but can occur extragenitally including the face.

2. Linear morphoea/scleroderma: Often presents as linear lesions with erythema progressing to hyperpigmentation.

3. Blaschkoid dermatoses: Following Blaschko's lines, can present with linear patterns of varying pigmentation.

4. Incontinentia pigmenti: Presents with linear vesicular lesions that evolve into hyperpigmented streaks.

Key Diagnostic Considerations

When evaluating a patient with linear hyperpigmented lesions on the forehead:

• Timing of onset: Piebaldism is present from birth, while acquired conditions develop later 4
• Stability of lesions: Piebaldism lesions remain stable throughout life, except in rare cases with specific mutations 3
• Distribution pattern: Piebaldism typically has a symmetrical distribution with characteristic white forelock 2
• Histopathology: In piebaldism, there is complete absence of melanocytes in affected areas
• Family history: Piebaldism shows autosomal dominant inheritance pattern 5

Conclusion

The described presentation of linear hyperpigmented lesions on the forehead with erythematous, hypo- and hyperpigmented variations is not consistent with piebaldism. A biopsy would be recommended for definitive diagnosis, particularly to rule out lichen sclerosus or other inflammatory dermatoses that can present with pigmentary changes 1.