Sebaceous filaments of the nose treated with a 1726-nm diode laser: A case report and description of the “Lunar crater sign”

Abstract

Figures

Baseline clinical photo of the nose showing prominent sebaceous filaments.Fig 2Dermoscopy (ILLUCO IDS-1100C, × 20): A, baseline showing *yellowish* follicular plugs; B, one month post-treatment showing *brown-to-tan* crateriform globules “Lunar crater sign.”

Post-treatment clinical photo of the nose at 4 weeks.

Full text

Case presentation

A 30-year-old man with no significant medical history, Fitzpatrick skin phototype IV, presented with prominent nasal sebaceous filaments for more than 5 years.

The patient was treated with topical retinoid (tretinoin 0.05 cream once daily) for 6 months with minimal improvement.

Dermoscopy (polarized contact, ILLUCO IDS-1100C, × 20) demonstrated uniform yellowish plugs consistent with sebaceous filaments.1 (Fig 1 and Fig 2, A).Fig 1. Baseline clinical photo of the nose showing prominent sebaceous filaments.Fig 2. Dermoscopy (ILLUCO IDS-1100C, × 20): A, baseline showing yellowish follicular plugs; B, one month post-treatment showing brown-to-tan crateriform globules “Lunar crater sign.”

Intervention

Device: AviClear (CUTERA), 1726-nm diode; integrated contact cooling.

Settings: Single session; 3.0-mm spot; fluence 18 J/cm^2^; 20 pulses; PRILA 5% (lidocaine/prilocaine cream) for 30 minutes before the procedure.

Immediate response included vaporization of the sebaceous material, without purpura or blistering.

Aftercare: Broad-spectrum sunscreen (sun protection factor 50).

Outcomes

At 4 weeks, clinical improvement was evident (Fig 3).Fig 3. Post-treatment clinical photo of the nose at 4 weeks.

Dermoscopy showed brown-to-tan crateriform globules, proposed as the “Lunar crater sign” due to resemblance to lunar craters (Fig 2, B).

Adverse effects: None reported by the patient, with no scarring or postinflammatory hyperpigmentation.

Discussion

Sebaceous filaments are physiologic accumulations of sebum and corneocytes in the follicular infundibulum and appear as uniform off-white/yellowish plugs on dermoscopy.1 They should be differentiated from trichostasis spinulosa and pityriasis folliculorum; prior reports describe improvement with topical keratolytics/retinoids.2

Light-based modalities such as intense pulsed light and the 1450-nm diode laser have previously been used to target sebaceous-gland activity, mainly in acne vulgaris and seborrhea.3 These devices achieve photothermal damage of sebaceous glands with transient sebum reduction. However, no prior reports describe their use for isolated sebaceous filaments. The 1726-nm wavelength offers greater lipid absorption and thus more selective sebaceous-gland photothermolysis.4

The 1726-nm wavelength targets sebum with higher absorption than water, enabling selective sebaceous-gland photothermolysis.4^,^5

Prospective acne cohorts demonstrate sebaceous-gland miniaturization and progressive lesion reduction durable to at least 26 weeks, with mostly transient erythema/edema and rare significant adverse effects.5, 6, 7

To our knowledge, 1726-nm treatment of isolated sebaceous filaments has not been specifically reported; this case suggests feasibility and motivates controlled evaluation.

Limitations

Single patient, short follow-up, no histology, and photography/lighting confounders.

Conflicts of interest

None disclosed.