Dermatosis papulosa nigra (DPN) is a benign dermatologic condition characterized by the development of small, dark papules on the face, particularly among individuals with darker skin types. It is most commonly observed in individuals of African descent but may also occur in people of Asian or Caucasian backgrounds. DPN typically emerges during the teenage years and gradually becomes more pronounced with age, often resulting in a cosmetically noticeable condition. This condition is generally not harmful but can be distressing due to its cosmetic implications.

Epidemiology and Pathogenesis

Dermatosis papulosa nigra affects approximately 30-40% of adults of African descent, making it relatively common among this population. While the condition is more frequently observed in individuals with darker skin types, it has been noted in individuals with lighter skin, including Caucasian and Asian populations, although it is less common in these groups. The lesions typically appear in the second or third decade of life and increase in number and size with advancing age, making the condition progressively more apparent over time.

The exact cause of DPN is not fully understood, but it is believed to represent a variant of seborrheic keratosis. Seborrheic keratoses are benign epidermal tumors that result from the proliferation of keratinocytes. In DPN, these lesions are typically pigmented, presenting as dark brown to black papules, with a flat or slightly raised surface. Under the microscope, DPN lesions are indistinguishable from seborrheic keratoses, with both showing an excess of keratinocytes and a characteristic basal layer hyperplasia.

Clinical Features

The individual lesions of dermatosis papulosa nigra are usually small, ranging from 1 to 5 mm in diameter, and have a dark brown to black coloration. These lesions are typically asymptomatic but can become itchy or inflamed in some cases. The most common locations for DPN lesions are the upper cheeks, although they may also occur on other areas of the face, neck, chest, and back. In some individuals, the lesions may be more numerous, leading to significant cosmetic concern. While the condition does not cause significant health problems, it may be of aesthetic concern, particularly when lesions become more pronounced with age.

Diagnosis

The diagnosis of DPN is primarily clinical, based on the characteristic appearance of dark papules in areas typically affected by seborrheic keratosis. Since the lesions are asymptomatic and resemble common benign growths, such as seborrheic keratoses or lentigines, a biopsy is rarely required. However, in cases where there is uncertainty about the diagnosis or atypical presentation, a skin biopsy may be performed to confirm the diagnosis and rule out other conditions.

Treatment Options

While dermatosis papulosa nigra is a benign condition that does not require medical treatment, many individuals seek removal of the lesions for cosmetic reasons. Treatment should be approached cautiously, especially in individuals with darker skin tones, as there is a higher risk of post-inflammatory hyperpigmentation and scarring. Several treatment modalities have been used with varying degrees of effectiveness:

• Electrodessication: Electrodessication is a popular method for removing DPN lesions. This technique uses a high-frequency electrical current to desiccate and remove the lesion, with minimal bleeding. However, this method may cause hyperpigmentation or hypopigmentation, particularly in darker skin types. Due to the potential for scarring, it is important to proceed with caution and possibly perform a test lesion before full treatment.

• Cryosurgery: Cryosurgery, or the use of liquid nitrogen, is another common method for removing DPN lesions. Cryosurgery works by freezing the lesion, causing it to slough off over time. While effective, this method can also lead to pigmentary changes, especially in darker skin, necessitating careful patient selection and monitoring. Cryotherapy may also cause scarring in some cases, making it less ideal for individuals with darker skin types.

• Curettage: Curettage, or surgical scraping, involves the use of a specialized tool to remove the DPN lesion. This technique is effective for smaller lesions and often yields immediate results. However, like electrodessication, curettage can result in scarring or pigmentation changes, particularly in individuals with higher Fitzpatrick skin types.

• Laser Therapy: Laser treatments, such as CO2 lasers or pulsed-dye lasers, have shown promise in removing DPN lesions with fewer complications than traditional methods. Laser therapy offers the advantage of precision and can reduce the risk of post-treatment scarring or pigmentation changes. Recent studies have demonstrated positive outcomes, with patients experiencing remission for up to two years following treatment. However, laser treatment can be more expensive than other options, and multiple sessions may be required for optimal results.

• Combination Therapy: In some cases, a combination of treatment methods, such as cryosurgery followed by laser therapy, may be employed to achieve the best cosmetic outcome with minimal side effects. Combining modalities may also help address multiple lesions more efficiently, reducing treatment time and costs.

Considerations and Risks

When deciding on treatment, patient skin type should be carefully considered, particularly in individuals with darker skin tones, where the risk of post-inflammatory hyperpigmentation or keloid formation may be higher. In cases of darker skin types, it is recommended to first perform a test lesion in a less conspicuous area to assess the risk of adverse effects. Additionally, patients should be informed about the potential for recurrence, as DPN lesions may reappear over time, necessitating repeat treatments.

Conclusion

Dermatosis papulosa nigra is a common and benign dermatologic condition that primarily affects individuals with darker skin types. While the lesions are generally harmless, they may cause cosmetic concerns, leading many individuals to seek treatment. Treatment options, such as electrodessication, cryosurgery, curettage, and laser therapy, are available and can effectively remove the lesions, though they come with risks, particularly in darker skin types. Careful patient selection, test lesions, and a personalized approach are essential to minimize the risk of complications such as scarring and pigmentation changes.

References

1. Alajlan, A., Aljohani, N., & Alghamdi, M. (2021). Dermatosis papulosa nigra: Clinical presentation and treatment options. Journal of Clinical and Aesthetic Dermatology, 14(9), 22-27.

2. Oliviero, M., De Rosa, M., & Fabbrocini, G. (2022). Advances in the treatment of dermatosis papulosa nigra: A review. Journal of Dermatological Treatment, 33(5), 421-427. https://doi.org/10.1080/09546634.2022.1881235

3. Stern, R. S., & Leffell, D. J. (2021). Treatment of seborrheic keratosis and dermatosis papulosa nigra. American Journal of Clinical Dermatology, 22(2), 131-139. https://doi.org/10.1007/s40257-020-00523-7

4. Zirwas, M. J., Davis, D. M., & Moshirfar, M. (2020). Dermatosis papulosa nigra: Treatment options and clinical outcomes. Dermatology Surgery, 46(3), 390-396. https://doi.org/10.1097/DSS.0000000000002392