Elective Treatment of Dermatosis Papulosa Nigra

Discussion

Given its benign nature, any elective treatment for DPN should balance results with potential adverse events including pain, dyspigmentation, scarring and recurrence. Patients must be clearly counselled that treatment is not medically necessary and that it will not change the natural history of this condition over time. They should be directed to providers with experience in treating skin of color.

When treating DPN, surgical modalities can require longer preparatory time for anesthesia. Bleeding can also be a problem for surgical excision or curettage, especially if multiple lesions are excised or if a patient is anticoagulated. Although a quick procedure, cryotherapy can cause significant pigmentary change, especially in skin of color. Electrodessication can result in satisfactory results, but pain is common and time should be allotted for anesthesia. Given their low costs and convenience, surgical modalities are widely available.

Laser treatment options for DPN are vast and summarized in Table 1. A major advantage to KTP or PDL lasers is the absence of pre-procedure anesthesia. The number of treatments depends on DPN size, wavelength chosen, laser settings, and operator technique. Given that the treatment zone is small, methods that help prevent damage to adjacent normal skin should be prioritized. The precise control of treatment is more difficult in surgical techniques, particularly in cryotherapy and curettage. Empirically in our practice, we preferentially use a long-pulse KTP laser with a small spot size and parallel contact cooling to precisely target DPN. Pulse-stacking is often necessary to reach a superficial whitening reaction on the lesion or until a faint "pop" is heard. Scaling and crusting of the lesions last for 5–10 days. Aftercare involves strict sun avoidance and liberal use of emollients until the treated areas have shed. The effectiveness, recovery and side effect profile of this modality has been very favorable in our hands (Figure 1). Anecdotally, patients who have experienced both KTP laser and electrodessication in the past have reported higher levels of satisfaction and more manageable "down time" with KTP laser.

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Figure 1.

Patient of South Asian descent pictured before and 8 weeks after one treatment session with a long-pulse 532-nm laser. The Excel V® laser by Cutera® was used at 11 J/cm² fluence, 3 mm spot size, 6 ms pulse duration, 10 degrees Celcius contact cooling and 1.0 Hz repetition. Pulse-stacking (3-4 pulses) was necessary to obtain the endpoint (faint popping sound or superficial whitening/scaling).

Hyperpigmentation is one of the most dreaded potential side effects when using surgical techniques to treat DPN. Postinflammatory hypo or hyperpigmentation can be mitigated with several techniques focusing on decreasing inflammation or melanin production post-procedure. There is, however, a lack of global evidence-based consensus regarding the most effective approach. Topical hydroquinone, usually in 2–4% concentration, can be used alone or in combination with tretinoin, azelaic acid or kojic acid as tolerated.^[30] Topical corticosteroids, both mid to high potency, have also been reported immediately after the procedure and for short durations to prevent post-inflammatory hyperpigmentation.^[31] Most importantly, strict pre and post-treatment sun avoidance should be recommended with broadspectrum ultraviolet (UV) A and UVB protection to prevent melanocyte stimulation. In the majority of studies identified in our review, post-inflammatory pigment changes in the treatment of DPN resolved within a year.

Table 1. Summary of published evidence on laser treatment for dermatosis papulosa nigra.
Year	References	Treatment	# of Treatments	# of Patients	Treatment Settings	Post-treatment	Results
Case Reports and Case Series
2001	Spoor T²³	Diode 532-nm	1–2	34	700 to 1000 microns spot size, 8–16 J/cm². Some patients required 4% topical lidocaine.	None	Treated lesions hyperpigmented then sloughed off over 3 weeks. Mild hypopigmentation in one patient which resolved. Overall, patient acceptance and response were excellent.
2007	Lupo MP²⁴	Diode 532-nm	Not reported	1	700 nm handpiece set at 12 J/cm², 2 W, 6 Hz, 15 ms pulse duration. No topical anesthetic.	Gentle cleanser	No pigmentary changes were noted.
2015	Karadag AS, et al.²⁶	PDL 585-nm	2–6	1	7 mm spot size, 8–9.5 J/cm², 10 ms pulse duration.	Not reported	Mild pain, post-procedural erythema and edema were observed but resolved. Good improvement after 2–6 sessions with no post-procedural complications or recurrence.
2008	Schweiger ES, et al.¹²	Nd:YAG 1,064-nm	1	2	Long-pulsed. No anesthesia. 3 mm spot size, 145–155 J/cm2, 20 ms pulse duration.	Petroleum jelly	Excellent results. 90% treated lesions had no pigmentary changes. Of the lesions with pigmentary changes, no post-treatment pigmentation was noted at 7 months.
2013	Bruscino N, et al.²⁹	CO₂ 10,600-nm	1–2	5	0.7 mm spot size, 0.5–0.7 W, 10 Hz. No surface anesthesia.	Topical antibiotic and sunscreen	Mild pain. Results were excellent and immediate with no recurrence at 8 months.
2016	Ali FR, et al.²⁸	CO₂ 10,600-nm	Not reported	18	Topical anaesthesia using EMLA cream. Test patch of laser ablation is undertaken using super-pulse mode (smaller papules; 1 W, 100 ms pulse) or resurfacing mode (larger plaques; 10 W, 2 mm spot size)	Soft paraffin ointment is applied daily	Median response was 9.5 (range 6–10) with 9 patients citing the maximum score of 10 for satisfaction. No post-procedure complications were noted.
Publications Comparing Treatment Modalities
2008	Joshi S, et al.²²	KTP 532-nm vs. electrodessication (split-face)	2	15	Not reported	Not reported	KTP laser and electrodessication were statistically equivalent for efficacy. Patients were less uncomfortable with KTP.
2009	Kundu RV, et al.¹⁹	KTP 532-nm vs. electrodessication (split-face)	2	14	15 J/cm², 10 ms pulse duration. No anesthesia.	Not reported	No significant treatment difference between KTP and electrodessication. KTP laser was preferred over electrodessication for comfort.
2010	Garcia MS, et al.¹⁷	PDL 585-nm vs. curettage vs. electrodessication (4 lesions selected: 1 for each therapy and a control)	1	10	7 mm spot size, 10 J/cm², 10 ms pulse duration.	4% hydroquinone cream applied BID, petroleum jelly BID, and photoprotection	Mean lesion clearance was 88% for lasercompared to 96% for curettage and 92.5% for electrodessication, but statically no difference. Patients rated the laser as most painful. Hyperpigmentation was noted in all 3 modalities.

Table 1. Summary of published evidence on laser treatment for dermatosis papulosa nigra.

Year

References

Treatment

# of Treatments

# of Patients

Treatment Settings

Post-treatment

Results

Case Reports and Case Series

2001

Spoor T²³

Diode 532-nm

1–2

700 to 1000 microns spot size, 8–16 J/cm². Some patients required 4% topical lidocaine.

None

Treated lesions hyperpigmented then sloughed off over 3 weeks. Mild hypopigmentation in one patient which resolved. Overall, patient acceptance and response were excellent.

2007

Lupo MP²⁴

Diode 532-nm

Not reported

700 nm handpiece set at 12 J/cm², 2 W, 6 Hz, 15 ms pulse duration. No topical anesthetic.

Gentle cleanser

No pigmentary changes were noted.

2015

Karadag AS, et al.²⁶

PDL 585-nm

2–6

7 mm spot size, 8–9.5 J/cm², 10 ms pulse duration.

Not reported

Mild pain, post-procedural erythema and edema were observed but resolved. Good improvement after 2–6 sessions with no post-procedural complications or recurrence.

2008

Schweiger ES, et al.¹²

Nd:YAG 1,064-nm

Long-pulsed. No anesthesia. 3 mm spot size, 145–155 J/cm2, 20 ms pulse duration.

Petroleum jelly

Excellent results. 90% treated lesions had no pigmentary changes. Of the lesions with pigmentary changes, no post-treatment pigmentation was noted at 7 months.

2013

Bruscino N, et al.²⁹

CO₂ 10,600-nm

1–2

0.7 mm spot size, 0.5–0.7 W, 10 Hz. No surface anesthesia.

Topical antibiotic and sunscreen

Mild pain. Results were excellent and immediate with no recurrence at 8 months.

2016

Ali FR, et al.²⁸

CO₂ 10,600-nm

Not reported

Topical anaesthesia using EMLA cream. Test patch of laser ablation is undertaken using super-pulse mode (smaller papules; 1 W, 100 ms pulse) or resurfacing mode (larger plaques; 10 W, 2 mm spot size)

Soft paraffin ointment is applied daily

Median response was 9.5 (range 6–10) with 9 patients citing the maximum score of 10 for satisfaction. No post-procedure complications were noted.

Publications Comparing Treatment Modalities

2008

Joshi S, et al.²²

KTP 532-nm vs. electrodessication (split-face)

Not reported

KTP laser and electrodessication were statistically equivalent for efficacy. Patients were less uncomfortable with KTP.

2009

Kundu RV, et al.¹⁹

KTP 532-nm vs. electrodessication (split-face)

15 J/cm², 10 ms pulse duration. No anesthesia.

Not reported

No significant treatment difference between KTP and electrodessication. KTP laser was preferred over electrodessication for comfort.

2010

Garcia MS, et al.¹⁷

PDL 585-nm vs. curettage vs. electrodessication (4 lesions selected: 1 for each therapy and a control)

7 mm spot size, 10 J/cm², 10 ms pulse duration.

4% hydroquinone cream applied BID, petroleum jelly BID, and photoprotection

Mean lesion clearance was 88% for lasercompared to 96% for curettage and 92.5% for electrodessication, but statically no difference. Patients rated the laser as most painful. Hyperpigmentation was noted in all 3 modalities.

Elective Treatment of Dermatosis Papulosa Nigra

A Review of Treatment Modalities

Discussion

Tables

References

Authors and Disclosures

Authors and Disclosures

Figure 1.

Figure 1.

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