What Is Nevus Comedonicus?

Medically Reviewed on 12/22/2022
What Is Nevus Comedonicus
Nevus comedonicus is a benign skin condition that is made up of groups of black plugs filled with keratin

Nevus comedonicus is an uncommon benign (hamartomatous) skin abnormality that is made up of groups of pits filled with dark keratin.

They are mostly found on the face and neck, although they can occur anywhere on the body including the head, trunk, limbs, and palmar and plantar regions. In most cases, they appear during birth, although some can appear in childhood.

Is nevus comedonicus rare?

Nevus comedonicus is fairly rare, affecting 1 in 45,000 people. 

Both men and women are equally affected by the condition.

What does nevus comedonicus look like?

The most common manifestation of nevus comedonicus is a defect in the development of the hair follicle, which results in a cluster of somewhat elevated keratinous papules with central keratinous plugs. 

Unilateral or bilateral lesions with a linear or zosteroid (resembling the appearance of herpes zoster) distribution are possible. These lesions may cause itching.

Clinically, nevus comedonicus can be separated into two categories:

  • Non-pyogenic nevus comedonicus with acne-like characteristics
  • Those characterized by the development of cysts, papules, pustules, and abscesses at different stages 

When nevus comedonicus is associated with systemic problems (such as skeletal, dental, neurologic, or ophthalmic), this condition is known as nevus comedonicus syndrome.

What is nevus comedonicus caused by?

No specific cause of nevus comedonicus has been established. However, it is believed to be caused by cutaneous mosaicism or a line of cells with a genetic defect. If this defect occurs early in the embryo's development, the cells may spread out and create many comedo nevi.

Nevus comedonicus is present in nevus comedonicus syndrome, which affects the brain, bones, and eyes. Other benign skin tumors, which are rarely associated with nevus comedonicus, include:

  • Trichoepithelioma
  • Hidradenoma papilliferum
  • Syringocystadenoma papilliferum
  • Keratoacanthoma
  • Pilar sheath tumor

The risk factors for nevus comedonicus are unknown. However, nevus comedonicus syndrome is a risk factor in rare cases.

It is important to understand that the presence of a risk factor does not guarantee that you will develop the condition. In addition, the absence of a risk factor does not rule out the possibility of developing the condition. It's always a good idea to talk to your medical provider about the effect of risk factors.

How is nevus comedonicus diagnosed?

In suspected cases of nevus comedonicus syndrome, a thorough examination of the central nervous system, skeletal system, and eyes is necessary. 

Lab tests

A skin sample will reveal the typically keratin-filled dilated follicular ostia. Immunohistochemistry tests have revealed overexpression of cellular markers, such as:

  • Proliferating cell nuclear antigen
  • Intercellular adhesion molecule-1
  • HLA-DR
  • CD68

Electron microscopy

Electron microscopy may reveal an increase in the number of Langerhans cells. With the history of early age of onset and the typical morphology, clinical diagnosis is usually clear. However, in the case of atypical presentations, other conditions to consider as differentials include:

  • Atypical acne, such as :
    • Segmental acne
    • Mosaic acneiform conditions
    • Chloracne
  • Favre-Racouchot syndrome (nodular elastosis with cysts and comedones)
  • Familial dyskeratotic comedones


Dermoscopy is done with a handheld tool with light and microscope and can detect comedonal lesions. Multiple light and dark brown, round, or barrel-shaped homogeneous areas with conspicuous keratin plugs are typical dermoscopy results.


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How do you treat nevus comedonicus?

Treatment of nevus comedonicus is necessary not only for cosmetic reasons but also to avoid complications such as suppurative infections and permanent scars. Since the lesions rarely turn cancerous, vigorous treatment is not necessary.

Treatment options include:

  • Topical retinoids
  • Keratolytic drugs
  • Oral retinoids
  • Antibiotic therapy
  • Manual extraction of comedones
  • Dermabrasion
  • Surgical excision of lesions
  • Laser removal of lesions

The most recommended therapy appears to be the complete removal of the lesion. A minor nevus is removed with a simple excision, which involves cutting off the diseased area and sewing the surrounding skin back together. 

Removing a large nevus can be difficult depending on its size and position, and additional cosmetic factors have to be considered.

Medically Reviewed on 12/22/2022
Image Source: Medscape image

Nevus comedonicus: https://healthjade.net/nevus-comedonicus/

NEVUS COMEDONICUS SYNDROME https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276921/#:~:text=Nevus%20comedonicus%20is%20an%20uncommon,inflammatory%20acne%20lesions%20developing%20later.