Multiple lentigines confined to a resolving psoriatic plaque

Area of Science:

• Dermatology
• Cutaneous Oncology

Background:

• Nevus spilus-like lentigines have been observed in psoriasis patients, often after phototherapy, suggesting UV light sensitivity.
• Post-inflammatory hyperpigmentation is another proposed mechanism for lentigines in resolving psoriatic lesions, even without phototherapy.

Observation:

• This report details a patient who developed nevus spilus-like lentigines on psoriatic plaques after treatment with topical calcipotriol.
• The patient had not undergone phototherapy or photochemotherapy prior to the development of these lentigines.

Findings:

• The development of nevus spilus-like lentigines following topical calcipotriol treatment suggests an alternative pathway for their formation.
• This case supports the hypothesis that post-inflammatory hyperpigmentation can manifest as lentigines in specific dermatological contexts.

Implications:

• Topical calcipotriol may induce nevus spilus-like lentigines through an unusual form of post-inflammatory hyperpigmentation.
• This finding broadens the understanding of iatrogenic pigmentary changes in psoriasis management and highlights potential side effects of topical treatments.