What is Dermatosis Papulosa Nigra?
Dermatosis papulosa nigra (DPN) is a harmless skin growth that appears as dark or skin-colored bumps on the face and neck, usually starting in the teenage years. It often develops in people with certain skin types (Fitzpatrick skin types III to VI), especially those of African and Asian heritage. DPN is considered a common form of seborrheic keratoses (SKs), a type of skin growth. The condition was first discovered in 1925 by Dr. Aldo Castellani, who noted it during his travels in Jamaica and Central America.
What Causes Dermatosis Papulosa Nigra?
The exact cause of DPN, a skin condition, is not yet known. However, research has found a similar gene mutation (in FGFR3) in both DPN and another skin condition called SKs. This discovery suggests that the two conditions could have a shared genetic cause. This might also be why some people seem more genetically likely to get DPN.
DPN usually appears on areas of the body that receive a lot of sun, like the head, neck, and upper trunk areas. This has led some to believe that exposure to ultraviolet (UV) light could play a role in causing the condition. Supporting this idea, the FGFR3 mutation becomes more common in areas of the skin exposed to the sun and as people get older.
One study found that patients with darker skin, who were using topical treatments to lighten their skin colour, experienced a worsening of their DPN symptoms. This could be because the loss of skin pigment reduced the skin’s natural protection against UV light. All these factors point to UV exposure possibly playing a part in the development of DPN.
Risk Factors and Frequency for Dermatosis Papulosa Nigra
DPN, a skin condition, is most common among people of African descent and fairly common among Asians. These study groups with darker skin tones have shown DPN cases ranging from 10% to 75%. It has been found in multiple racial and ethnic groups such as Africans, Filipinos, Vietnamese, Europeans, and Mexicans. Notably, up to a third of African American adults in the United States have DPN. Lighter-skinned African Americans are found to have a lower rate of DPN compared to those with dark skin.
- There is a strong tendency for DPN to run in families; between 77% to 93% of patients with DPN have family history of the condition.
- Women are twice as likely to be affected as men.
- Typically, DPN begins in adolescence, unlike similar skin conditions such as SKs.
- Although it’s rare, it can occur in children, with cases reported in children as young as 3.
- The number and size of DPN lesions can increase with age, usually reaching a peak in one’s sixties.
- DPN is not linked to any diseases or syndromes, but in rare cases, it has been associated with colon cancer (adenocarcinoma).
Signs and Symptoms of Dermatosis Papulosa Nigra
Dysplastic nevus syndrome, also known as DPN, usually starts showing up in teenagers. The signs of this condition first appear as small, round spots on the skin that might look like freckles. These spots vary in color from skin-toned to dark brown. As time goes on, these “freckles” transform into raised bumps, and more show up. The bumps become a little bigger, too, increasing to between 1-5mm in size and 1-3mm in height. These might get darker over time.
The most common places for these bumps to show up are on the cheeks, temples and forehead. But they can also occur on the neck, upper chest, and back, though less frequently. About one out of every four people with these bumps on their face will also have them on their body. The bumps don’t hurt or itch and don’t form scales, crusts, or sores. Once they appear, they don’t go away on their own.
- Starts appearing in adolescence
- Begins as small, round spots that resemble freckles
- Transforms into raised bumps that grow in size and number over time
- Commonly occur on cheeks, temples, and forehead; can show up on neck, upper chest, and back
- One in four patients with facial bumps will also have them elsewhere on the body
- Bumps are not painful or itchy and don’t form scales, crusts, or sores
- They don’t go away by themselves
Testing for Dermatosis Papulosa Nigra
Dermatopathia pigmentosa reticularis (DPN) is a condition that can typically be identified by a healthcare professional through examination. Dermoscopy, a method that involves observing the skin using a special magnifying tool, can be a cost-effective and noninvasive way to diagnose this condition and differentiate it from other skin problems that have similar appearances.
In a study from 2017, researchers found that the most common visible characteristic under a dermoscope was a pattern of cracks and lines that look similar to a brain’s surface; this was seen in 59% of cases. Another feature often spotted was what’s known as comedo-like openings, which were seen in 27% of the cases. Small, milia-like cysts and a combination of these signs could also be seen.
If there is any worry that a skin lesion could be cancerous, it’s recommended to take a sample of it and send it to a laboratory for further examination.
Treatment Options for Dermatosis Papulosa Nigra
Treatment for DPN, or seborrheic keratosis, isn’t always needed and is usually done for aesthetic reasons. People with darker skin should be cautious about treatment options due to the risk of changes in skin color following treatment. Before deciding on a course of treatment, a few lesions should be tested first to see how the skin reacts to avoid discoloration or scarring.
The usual treatment methods involve removing the lesions with scissors, a technique called snip excision, or lightly scraping them off with a curette. Both methods can be done with or without anesthesia. Small lesions can also be treated with a gentle use of electric current, called electrodesiccation, after applying a numbing cream. The patient should then apply an ointment to the treated area until it fully heals.
Using cold temperature treatment or cryotherapy can be risky due to the potential for skin lightening caused by damage to the pigment-producing cells, or melanocytes. So, this method should only be used very carefully.
Various laser treatments – specifically, KTP, PDL, Nd:YAG, and CO2 lasers – have shown promising results in the treatment of DPN lesions. Side effects are usually minimal, and these lasers work as effectively as electrodesiccation. It might take more than one laser treatment to achieve the desired results.
A study conducted in 2016 included 45 patients who were treated with a CO2 laser. Most patients were happy with their appearance following an average of three treatment sessions. However, it should be noted that 28% reported some lesions returning after CO2 laser treatment. This highlights the importance of letting patients know that lesions can return after using any treatment method.
What else can Dermatosis Papulosa Nigra be?
When diagnosing DPN (Dermatosis Papulosis Nigra), a skin condition that primarily affects darker skin tones, doctors need to consider other similar skin conditions, such as:
- Seborrheic keratoses (non-cancerous skin growths)
- Acrochordons (also known as skin tags)
- Verrucae (commonly known as warts)
- Melanocytic nevi (moles)
- Angiofibromas (benign, small, red or purple growths)
- Various growths related to hair, oil, or sweat glands, including trichoepitheliomas, fibrofolliculomas, tricholemmomas, basaloid follicular hamartomas, and syringomas.
These conditions can often resemble DPN, so doctors need to carry out appropriate investigations to confirm the correct diagnosis.
What to expect with Dermatosis Papulosa Nigra
DPN, or Dermatosis Papulosa Nigra, is a harmless skin condition that doesn’t pose any threats of turning into cancer. Over time, DPN spots may become more numerous and larger in size, and they don’t typically disappear on their own.
Possible Complications When Diagnosed with Dermatosis Papulosa Nigra
Just like seborrheic keratoses, DPN lesions can also get inflamed and irritated. Removing these lesions could lead to certain cosmetic issues, which include infection, scarring, and changes in skin color.
