Plantar cutaneous pili migrans in a middle-aged woman: Dermoscopy-guided diagnosis challenging pediatric predominance

Cutaneous pili migrans (CPM), a rare dermatologic entity characterised by migratory hair fragments embedded in the skin, is frequently misdiagnosed due to its nonspecific presentation.¹ While most reported cases involve children with plantar lesions secondary to barefoot activities, adult-onset CPM remains very rare.² We present a diagnostically challenging case of plantar CPM in a 46-year-old woman, initially misdiagnosed as a plantar wart, and highlight the pivotal role of dermoscopy for diagnostic accuracy.

A 46-year-old woman presented to our dermatology clinic with a 3-month history of a painful, well-demarcated, pale yellow, roundish cutaneous lesion on her right sole [Figure 1]. The lesion was initially suspected to be a plantar wart due to its hyperkeratotic appearance. However, dermoscopic examination (polarised mode, ×20 magnification) of the plantar creeping eruption revealed an ill-defined, faint erythematous patch on the right sole. A homogeneous, yellowish, round structure was observed centrally, within which a dark U-shaped curled hair fragment was seen obliquely embedded in the yellowish keratinous material. The distal end of the hair was located deeply, while the curved portion lay superficially. The overlying epidermis remained intact [Figure 2]. No dotted vessels or thrombosed capillaries, typical of viral warts, were observed. Under sterile conditions, mechanical extraction was performed using a 25-gauge needle, successfully retrieving a 2-cm hair fragment from the proximal end of the tract [Figure 3]. The lesion resolved completely within 14 days without recurrence at 8-week follow-up.

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Figure 1:

A linear, black hair-like structure with a pale yellowish keratotic lesion at the base.

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Figure 2:

Dermoscopy of the right sole showing an erythematous track with an embedded hair fragment (polarised mode, 20x).

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Figure 3:

A 2-cm dark hair was extracted from its epidermal bed.

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This case expands the clinical understanding of CPM in three critical aspects. First, CPM is vastly underreported in adults, particularly in middle-aged individuals. A PubMed review (1957-2025) identified 13 cases of plantar CPM, including five adult patients of which only one patient is older than 35 years.^3-8 To our knowledge, our case represents the second case with age over 45 years and the first adult Asian female, challenging the notion that plantar CPM is restricted to paediatric populations.⁵ Second, the initial misdiagnosis as verruca underscores the importance of dermoscopy in differentiating CPM from common plantar lesions. Unlike warts, CPM lacks vascular patterns but may show subtle hair fragments or keratin plugs.⁴ Third, mechanical stress from prolonged barefoot walking, as reported by the patient, may predispose adults to hair penetration through microtraumas, even without overt trauma.⁵

The pathogenesis of CPM remains unclear, but mechanical friction and compromised skin barriers likely facilitate hair migration. Dermoscopy is invaluable in avoiding diagnostic pitfalls, as clinical features often resemble infections or inflammatory dermatoses. Early extraction prevents complications such as secondary infection or chronic inflammation.

In conclusion, this case highlights that CPM should be considered in adults with pale yellowish plantar keratotic lesions, regardless of age. Dermoscopy is a low-cost, rapid tool for aiding diagnosis, particularly in resource-limited settings. Increased awareness of CPM’s varied presentations will reduce misdiagnosis and guide timely intervention.