The Impact of Pigmentary Demarcation Lines

This blog series highlights conditions that have a strong impact on people of color and appears as part of Project IMPACT: Improving Medicine’s Power to Address Care and Treatment.

Pigmentary demarcation lines (PDLs) represent a benign, asymptomatic, and normal variant condition involving altered pigmentation. PDLs were first described by Austrian anatomist and renowned hair and skin researcher Christian August Voigt in the mid-1800s. They were also later described by internist Palmer Howard Futcher in 1938. PDLs, therefore, may also be referred to as Voigt lines, Futcher lines, or Voigt-Futcher lines. It is important that physicians understand these normal variations in pigmentation, particularly among populations of color, to mitigate patient anxiety and avoid unnecessary diagnostic workup and treatment.

PDLs are most common among individuals with skin of color, especially Black individuals, followed by Hispanic and Asian individuals. PDLs may appear at birth or in early childhood, and there is a slightly higher incidence in females.

While the pathogenesis is unknown, there are several theories regarding their etiology and pathophysiology. It is suspected that PDLs are physiologic. However, previous studies suggest that PDLs may correspond with areas of pigmentary mosaicism, cutaneous nerve distribution, peripheral cutaneous innervation, and/or hormonal changes.1

There are 8 known types of PDLs (A to H), depending on anatomic location.

  • Group A refers to those lines that occur along the upper extremities, with occasional trans-pectoral extension.
  • Group B lines typically occur along the posterior lower extremities. While most PDLs persist throughout life, group B lines may occur during pregnancy and spontaneously regress after delivery.
  • Group C lines occur in or near the middle of the chest and may extend down the midline of the abdomen. Group C lines include linea alba, which is a vertical hypopigmented line extending from the chest to the abdomen, and linea nigra, a vertical hyperpigmented line extending from the suprapubic region to the umbilicus.2,3
  • Group D refers to demarcation lines on or near the spine.
  • Group E lines are bilateral and symmetric obliquely shaped hypopigmented macules that appear on the medial chest.
  • Group F lines appear as inverted V-shaped patches along the lateral cheek or temple that either point inferiorly or inferolaterally.
  • Group G lines form a W-shaped patch with a rim of normal pigmentation in the same location. Finally, group H lines are diagonal lines that extend from the oral commissures to the lateral chin.

Diagnosis is typically clinical. A biopsy is not necessary. Under light microscopy, both sides of the PDL have similar melanocyte concentrations.

PDLs are typically persistent, although some may spontaneously regress.

How do pigmentary demarcation lines impact people of color?

PDLs are physiologic, sharp demarcations between more heavily pigmented and lightly pigmented skin. They are most prevalent in populations of color and are thought to have a slightly increased predominance among females, although this may be secondary to increased cosmetic concern among this population and bringing it to a physician’s attention. For many individuals, PDLs can be troubling cosmetically and cause significant psychosocial distress.

What to look for:

Physical examination typically reveals well-demarcated lines separating an area of darker skin from areas of lighter skin. They are often bilateral but may appear unilaterally.

Differential:
Diagnostic Pearls:

The areas of demarcation occur in 1 of the 8 known anatomic locations associated with pigmentary demarcation lines.

Treatment:

Treatment is not necessary and benign reassurance should be provided to those seeking care. Some patients may also consider camouflaging with makeup if they desire.1

Sources:
  1. Zieleniewski ?, Schwartz RA, Goldberg DJ, Handler MZ. Voigt-Futcher pigmentary demarcation lines. J Cosmet Dermatol. 2019;18(3):700-702.
  2. Shelley ED, Shelley WB, Pansky B. The drug line: The clinical expression of the pigmentary Voigt-Futcher line in turn derived from the embryonic ventral axial line. J Am Acad Dermatol. 1999;40(5):736-740.
  3. George AO, Shittu OB, Enwerem E, Wachtel M, Kuti O. The incidence of lower mid-trunk hyperpigmentation (linea nigra) is affected by sex hormone levels. J Natl Med Assoc. 2005;97(5):685-688.
  4. Bieber AK, Martires KJ, Stein JA, Grant-Kels JM, Driscoll MS, Pomeranz MK. Pigmentation and pregnancy: knowing what is normal. Obstet Gynecol. 2017;129(1):168-173.
  5. Kelly AP, Heidelberg KA. Nuances in skin of color. In: Kelly AP, Taylor SC, Lim HW, Serrano AMA, eds. Taylor and Kelly’s Dermatology for Skin of Color. 2nd ed. McGraw-Hill Education; 2016. Accessed August 17, 2020. accessmedicine.mhmedical. com/content.aspx?aid=1161545089

This Project IMPACT blog series was created to highlight dermatologic conditions that disproportionately affect people of color. By improving diagnosis in skin of color we can reduce racial disparities in healthcare.

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