What is Nevus Comedonicus?
Nevus comedonicus (NC), first identified by Kofmann in 1895, is an uncommon condition that is classified as a type of skin birthmark called an epidermal nevus. This condition appears as clusters of enlarged skin pores filled with dark, hardened skin oils, also known as keratin plugs. Originally, Kofmann proposed calling this condition ‘comedo nevus.’
What Causes Nevus Comedonicus?
The exact cause of Nevus comedonicus, a type of skin condition, is not fully understood. One belief is that it’s a type of skin birthmark known as an “epidermal nevus” that develops from the hair follicle – the tiny sac from which hair grows. Another theory is that it’s a sort of growth called a “hamartoma,” which is a benign, or noncancerous, tumor-like formation that originates from the mesodermal part of the pilosebaceous unit – the structure within our skin that includes the hair follicle and oil gland.
Additionally, some think the condition may be due to something known as “genetic mosaicism.” This is a condition in which cells within the same person have a different genetic makeup. It is thought that this might play a role in the development of Nevus comedonicus.
Risk Factors and Frequency for Nevus Comedonicus
The likelihood of having this condition ranges from 1 in 45,000 to 1 in 100,000 people. It does not favor a specific gender – both males and females are equally likely to get it. In addition, it doesn’t affect one ethnicity more than another. Most people who develop this condition do so before they turn ten years old.
Signs and Symptoms of Nevus Comedonicus
Nevus comedonicus, a skin condition, usually develops shortly after birth or before the age of ten for most patients. This condition typically affects areas such as the face, neck, upper arms, chest, and abdomen. It’s less common for areas like the scalp, palms, and the glans penis to be affected. Generally, the condition presents itself as a single group of dilated and plugged follicular ostia, which looks like a honeycomb pattern. However, different patterns can appear, such as linear, segmental, or Blaschkoid. In rare cases, the lesions may be bilateral, meaning they appear on both sides of the body.
There are two specific subtypes of Nevus comedonicus identified:
- A non-pyogenic type which doesn’t lead to pus formation
- A type associated with the formation of cysts, pustules, and abscesses
Nevus comedonicus can occur by itself or along with systemic abnormalities in the central nervous system, skeletal system, other skin manifestations, or ocular and dental abnormalities. If it occurs in combination with these abnormalities, it is known as nevus comedonicus syndrome.
Testing for Nevus Comedonicus
If your doctor suspects you have NC syndrome, they will typically examine your nervous system, your bones, and your eyes in detail. They might also take a small sample of your skin to examine under a microscope. This could show enlarged hair follicles filled with a protein called keratin, which is a common sign of this condition.
Your doctor might also run tests to measure levels of certain proteins and cells that are often higher in people with this condition. These include proliferating cell nuclear antigen, a protein involved in cell growth; intercellular adhesion molecule-1, a protein that helps cells stick together; HLA-DR, a protein that plays a key role in the immune system; and CD68, a marker for a type of immune cell.
Typically, if you have NC syndrome, you’ll have started showing symptoms at a young age, and these will have taken on a specific form. However, there are other conditions that can appear similar, including unusual types of acne, other skin conditions that resemble acne (for instance due to exposure to certain chemicals), and nodular elastosis with cysts and comedones, which involves the formation of nodules and small skin lesions. An inherited condition called familial dyskeratotic comedones, characterized by hardened, pimple-like lesions, also needs to be considered.
A recent development is the use of a technique called dermoscopy to help diagnose NC syndrome. Dermoscopy is a non-invasive technique that allows doctors to examine the skin in detail. For NC syndrome, it might show a pattern of light and dark brown circular or barrel-shaped areas with clear keratin plugs.
Treatment Options for Nevus Comedonicus
Nevus comedonicus, a skin condition that involves clusters of blackheads, doesn’t simply go away on its own. However, because it’s generally harmless, aggressive treatment is usually not necessary. Typically, treatment is only sought out for appearance-related reasons or if complications arise, such as the development of cysts or abscesses. Occasionally, you may also need treatment to reduce scarring left by skin inflammation.
When it comes to treating nevus comedonicus, there are a few options. One possibility is medications called retinoids, which can be applied directly to your skin or taken orally. These are sometimes given along with steroid creams to reduce inflammation, salicylic acid, or a solution containing 12% ammonium lactate, a moisturizer that can help soften the blackheads.
Another potential line of treatment is surgery or laser treatments. In fact, various types of lasers — ultrapulse carbon dioxide lasers, erbium-YAG lasers, and a 1450 nm diode laser — have been used effectively in treating this condition. A 1450 nm diode laser, for instance, is thought to potentially reduce skin dents by stimulating the growth of collagen, a protein that helps maintain skin structure underneath the skin.
Other traditionally less common treatments for nevus comedonicus include using a pore strip to remove the keratin plugs (the substance trapped in the blackheads) and utilizing medications designed to interrupt certain biochemical pathways in the body via FGFR inhibitors, interleukin-1-alpha inhibitors, and anti-gamma-secretase drugs.
Overall, while this condition may require treatment mostly for aesthetic purposes or to manage complications, there are a variety of methods available depending on the needs and circumstances of each individual patient.
What else can Nevus Comedonicus be?
Here are some possible skin conditions a doctor might consider:
- Acne in newborns (Acne neonatorum)
- Common acne (Acne vulgaris)
- Angiokeratomas (small dark spots on the skin)
- Severe forms of acne (Chloracne and acne conglobata) with extensive blockages (comedones)
- Skin growth (Epidermal nevus)
- Skin cyst (Epidermoid cyst)
- Inherited skin condition (Familial dyskeratotic comedones)
- Skin condition caused by sun exposure (Favre-Racouchot syndrome)
- Acne in infants (Infantile acne)
- Skin condition causing small bumps (Keratosis pilaris)
- Skin condition affecting children (Lichen striatus)
- Congenital skin condition (Nevus sebaceus)
- Genetic disorder causing skin abnormalities (Tuberous sclerosis)
Correct diagnosis of these conditions requires a detailed examination and sometimes specific tests.
