Chapter 49: Dermatosis Papulosa Nigra

INTRODUCTION

Dermatosis papulosa nigra (DPNs) are very common benign brown warty papules that appear in African Americans and other patients with dark skin phototypes, DPNs usually affect the cheeks, neck, and upper chest (Fig. 49.1). DPNs are a type of seborrheic keratosis. Many patients request removal of DPNs, particularly when multiple or large, due to their unsightly appearance.

EPIDEMIOLOGY

Incidence: very common in African Americans and Asians

Age: second decade to middle age

Race: more common in African Americans and Asians

Sex: females > males (2:1)

Precipitating factors: strongly associated with family history

PATHOGENESIS

Unknown.

PATHOLOGY

DPNs feature hyperkeratosis, papillomatosis, and acanthosis as seen in seborrheic keratoses. No squamous eddies are present.

PHYSICAL LESIONS

They present in a symmetric fashion as small brown smooth sessile papules on the face, neck, and upper trunk of African Americans and Asians. They range from 1 to 5 mm in diameter and are often pedunculated.

DIFFERENTIAL DIAGNOSIS

Seborrheic keratosis, lentigo, verruca, acrochordon, melanocytic nevus, angiofibroma, and adnexal tumors are all in the differential diagnosis.

LABORATORY EXAMINATION

None.

COURSE

They present during teenage years. Over time, they become larger and more numerous, peaking in middle age. They do not regress spontaneously.

KEY CONSULTATIVE QUESTIONS

Family history of DPNs.

MANAGEMENT

There is no medical indication to treat DPNs, unless they are irritated. Still, the cosmetic appearance bothers many patients particularly when numerous. There are multiple modalities for treating DPNs including cryotherapy, electrodessication, gradle scissor removal, curettage, and ablative laser therapy. Primary consideration before treatment should be the effective removal of the DPNs without producing pigmentary change.

TREATMENTS

• Shave or gradle scissor excision can effectively remove DPNs

  • – Local infiltration with local anesthesia followed by gradle scissor removal is safe, fast and has the lowest risk of postinflammatory dyschromia

• Cryotherapy

  • – Light cryotherapy is a quick, inexpensive, slightly painful, and effective method of treating DPNs

  • – Caution: cryotherapy can produce hypopigmentation by destroying melanocytes. Hyperpigmentation can also occur

• Light electrodesiccation and curettage

  • – Light electrodesiccation of DPNs is another quick and effective method of treatment. There is a risk of postinflammatory dyschromia

  • – With light electrodesiccation, the lesion will turn white

• Only light electrodesiccation should be employed to decrease the risk of pigmentary changes

LASER TREATMENTS