Dermatosis Papulosa Nigra DPN Treatments

A SummaryTreating DPN spots

In our practice, a dermatologist is often required to perform DPN removal, not because they are challenging to treat, but because of the hand holding (patient concerns with emails, phone calls & concerns) post removal. If a nurse performs this treatment in exactly the same way, in over half the cases, some patients will escalate their concerns to see a dermatologist- hence why we task this procedure for our doctors.  The primary concern/s are post inflammatory hypopigmentation & hyperpigmentation, which, in over 96% of cases are self limiting. 

Concept of skin healing in darker skin types

It is important to understand the healing process of darker skin types as this is ingrained in our DNA. For effective DPN removal, the upper layers of skin must be removed with the DPN lesion itself. This WILL leave transient hypopigmentation, namely slightly white patches of skin, the diameter of which corresponds to the width of DPN. This is due to the fact that we remove melanin (pigment) & melanocytes (pigment cells) within the lesion of dermatosis papulosa itself. 

Hypopigmentation is transient, self correcting within 3 to 6 weeks. From there skin may be hyperpigmentation (darker) than the surrounding facial skin. This may last another 4 to 8 weeks, depending on your skin type (colour) & background UV-visible light exposure. 

Apart from 2 factors that you can alter, this course of healing can not be changed. The factors include- 

1. Use of sunscreen 10 to 28 days after the procedure can reduce the changes of post inflammatory hyperpigmentation (darkening).
2. Azelaic acid or vitamin C for dark pigmented spots post healing, should they occur.

Treatment options for DPN encompass various surgical techniques, such as cryotherapy, curettage, and electrodessication, alongside laser therapy. Numerous laser therapies for DPN have been documented, including the 532-nm potassium-titanyl-phosphate (KTP) laser, 532-nm diode laser, 585-nm pulsed dye laser (PDL), 1064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, 1550-nm erbium-doped fractionated laser, and the 10,600-nm carbon dioxide (CO2) laser. 

At the Melasma Clinic, our specialist will elect to use a combination of techniques to offer you the best clearance rates (often 80-90% in one session), with the least amount of side effects. We are trained in all techniques of DPN removal, from the very latest lasers, through to electrosurgery, freezing & pin-point chemical peels. 

Excision

The use of simple shave (blade) or scissor excision for treating DPN is generally well tolerated, with bleeding, erythema, and edema being the most commonly observed acute adverse events. Pedunculated lesions of DPN are particularly suitable for scissor excision. Fine curved scissors are commonly employed, either with or without local anesthesia, and post-procedure wound care typically involves the application of petrolatum or topical antibiotics. 

Although there are limited studies reporting outcomes for scissor excision, adverse events are expected to be similar to other surgical excisions of epidermal lesions, including pain, hemorrhage, dyspigmentation, scarring, and recurrence

Cryotherapy

Cryotherapy offers the advantages of being cost-effective and rapid, with minimal pre-procedure preparation. This treatment is frequently used in skin cancer clinics by ‘professional’ skin cancer ‘specialists’. 

The number of treatments and freeze-thaw cycles may vary depending on the depth of the lesion and provider technique. A primary concern with this modality in patients with skin of color is hypopigmentation, resulting from damage to melanocytes in the underlying or surrounding healthy skin. Cryotherapy should be used cautiously in such cases. Employed by real professionals, the results are quite good. 

Curettage

Curettage is another surgical option for the removal of epidermal tumors. Similar to cryotherapy, the cost of curettage is minimal. Different sizes of curettes can be employed based on the size of DPN, my preferred is either a 2 or 4 mm sharp disposable for this job. 

Anesthesia is typically administered before the procedure; however, studies have reported successful treatment without anesthesia and minimal adverse outcomes. Light abrasive curettage without local anesthesia has been described as an effective treatment for DPN, with no scarring reported in some cases. In one study, curettage demonstrated higher mean clearance rates compared to electrodessication and pulsed-dye laser for DPN treatment, although the differences were not statistically significant. The main concern with curettage is the risk of pigment changes, which resolve within 40 days. 

Electrodessication

Electrodessication is a common method used to treat various epidermal tumors, including seborrheic keratoses, warts, acrochordons, and DPN. Typically, wall-mounted electrosurgical units are employed for treating DPN, with voltage settings adjusted gradually, typically ranging from 0.9 to 1.8 W. We use the Aaron Bovie units with modified needle tips for this job.  

Patients may experience discomfort during the procedure. Local or topical anesthesia is administered beforehand. Studies comparing electrodessication with other treatments such as KTP laser have shown comparable efficacy in improving DPN lesions, although patients tend to prefer the KTP laser due to its comfort. Notably, some studies have reported favorable cosmetic outcomes with electrodessication compared to other modalities like PDL and curettage.

532-nm Potassium-titanyl-phosphate Laser 

The 532-nm KTP laser is commonly used for treating vascular skin lesions and pigmented lesions, including DPN. Studies have demonstrated its efficacy in improving DPN lesions, with patients reporting less pain and more favorable outcomes compared to electrodessication. Similarly, the 532-nm diode laser has shown excellent treatment response with minimal postinflammatory hypopigmentation.

The Melasma Clinic has 2 such lasers; the Excel V and the Derma V at 532 solid state KTP. Having said this, I prefer the erbium or CO2 lasers, or better still, a de-focused Picosure Pro laser using a small spot size, rather than turning off the contact cooling on these laser devices. Heat itself can treat DPN lesions, at the expense of an increased incidence of post inflammatory hyperpigmentation. 

Pulsed Dye Laser

The 585-nm PDL is effective for vascular skin conditions and can also target melanin-containing structures. Treatment with PDL has shown similar outcomes to other modalities like curettage and electrodessication, although it may be more painful. However, favorable improvement and outcomes have been reported with specific settings, albeit requiring multiple sessions to achieve optimal results.

I do NOT use the PDL for DPN as the rate of PIH is high. There are far better lasers for this job. Turning the cooling or DCD function off on the pulse dye laser is asking for trouble. 

Q-switched and Picosecond Lasers

Q-switched and picosecond lasers targeting pigment wavelengths are used in clinical practice to treat DPN. Picosecond lasers are believed to reduce the risk of postinflammatory hyperpigmentation due to their shorter pulse duration. We use a de-focused 2 mm spot on the 755 Picosure Pro at high fluence to photoacoustic ablate DPN lesions. Pico lasers have the advantage of blending in areas of pigment (pigment reduction). Using the de-focus function of pico we can alter the spot size from 2 mm, down to 0.3 mm, making this a very precise tool for treating super small DPN lesions. 

Pico lasers offer significant advantages over other lasers, as this can markedly improve other forms of pigmentation such as melasma, age spots, freckles & sunspots, as they frequently occur in patients who are predisposed to DPN. 

Resurfacing Lasers: Erbium 1550 ablative laser; small spot size

Non-ablative resurfacing has emerged as the preferred treatment method for various aesthetic concerns due to its shorter downtime and lower risk of complications. Water-targeting lasers with a non-ablative approach offer effective results with minimal side effects. A case report demonstrated successful DPN treatment using a 1550-nm wavelength erbium-doped laser, employing specific parameters, treatment level 7, 20% coverage, and 2.42-2.94 kJ total energy, administered over 3 treatments with multiple passes. Prior to treatment, a topical anesthetic was applied to minimize discomfort.

We employ a specific 0.5 to 1 mm focused spot size using the erbium Sciton device at a rep rate of 2 to 6 hz. Level of 10 -30 microns. 

Carbon dioxide (CO2) Laser; 10,600 nm 

Ablative lasers represent another well-established option for treating epidermal tumors. Among them, the carbon dioxide laser stands out as one of the oldest and widely used ablative laser devices, with extensive clinical experience in addressing various skin conditions, including nevi, verruca, keloids, and acne scarring. 

A retrospective study indicated high patient satisfaction and minimal post-procedural complications with CO2 laser treatment for DPN, despite a 28% recurrence rate. Using specific settings such as a spot size of 0.7 mm, 0.5-0.7 W, and 10 Hz, Bruscino et al. achieved excellent treatment response in female patients with DPN, with no instances of recurrence.

I use the Deka laser as well as the Ultrapulse with a 1 mm spot size to treat these lesions. CO2 is a fast, reliable way to treat DPN lesions. We also employ the Lutronic eCO2 with the dynamic mode pin point setting, low Hz, modest power to precisely ablate DPN lesions.