What Is Porokeratosis?

Written by Bethany Afshar
Medically Reviewed by Zilpah Sheikh, MD on June 18, 2025
4 min read

Porokeratosis is a skin condition marked by raised brown bumps that may expand into scaly patches. They often have raised rings around the spots. Porokeratosis is not contagious, but it may be passed down through families. It most commonly affects children and young adults.

The exact cause of porokeratosis is not known, but genetic factors and having a weak immune system may put you at a greater risk for the condition. Sunlight, UV rays, and other radiation worsen the condition.

The specific triggers for different types of porokeratosis may vary.

Here are the main types of porokeratosis:

  • Porokeratosis of Mibelli. It affects children and young adults and is twice as common in men as in women. It appears as discolored raised bumps with a thin border — most often on the torso, arms, and legs.
  • Disseminated superficial actinic porokeratosis (DSAP). It affects adults, especially women, and is most commonly related to UV exposure and sun damage. It appears as red and brown spots, mostly on the back, arms, legs, and shoulders. 
  • Disseminated superficial porokeratosis (DSP). It typically develops in children and looks similar to DSAP, but it can show up even in areas not exposed to the sun. 
  • Porokeratosis palmaris et plantaris disseminata. It usually strikes people in adolescence or young adulthood. It looks like scaly, round patches on the palms of your hands and the bottom of your feet.
  • Linear porokeratosis. It occurs mostly during early childhood. Its appearance is similar to DSAP or DSP. 
  • Punctate porokeratosis. It affects adults. It appears as small, ridge-like bumps on the palms of your hands and the bottom of your feet. These bumps can be itchy and spread slowly.
  • Eruptive disseminated porokeratosis (EDP). It also features itchy, small, ridge-like bumps that appear mostly on your arms, legs, and trunk. Unlike other forms of porokeratosis that develop slowly over time, EDP occurs suddenly.

What is the most common form of porokeratosis?

‌Disseminated superficial actinic porokeratosis and porokeratosis of Mibelli are the two most common types of porokeratosis.

If porokeratosis is left untreated, it may worsen, causing the patches to grow larger.

‌If you notice patches of brown bumps that appear to grow and spread, talk to your doctor. While the skin condition may be harmless, it’s better to get a professional opinion. Some types of porokeratosis may increase your risk of skin cancer by as much as 19%.

Porokeratosis spots often have a rough, raised border that may look like ringworm. The rashes are different because ringworm is caused by the fungus tinea corporis and is contagious, unlike porokeratosis. Ringworm is also slightly different in appearance. The raised ring is usually red, and the center of the spot is either the same color as your flesh or slightly paler. If you’re not sure how to distinguish between the two skin conditions, talk to your doctor.‌

You can easily treat ringworm at home with an over-the-counter antifungal cream. If you use an antifungal cream on porokeratosis, you won’t see the results you expect. Instead, your condition may continue to worsen.

A diagnosis of porokeratosis relies on a physical exam and sometimes a biopsy. Your doctor will physically examine your affected skin patches and use a tool called a dermatoscope, which lights up and magnifies the skin surface.

If a diagnosis is still unclear or if there is a concern about the possibility of cancer or other conditions, your doctor may do a biopsy of the affected skin.

There is no cure for porokeratosis, but treatments are available. Your exact treatment will depend on the severity and type of porokeratosis as well as other health conditions you have. In some cases, your doctor may opt to wait and watch, keeping an eye on the affected areas to see if the spots go away on their own. Or they may opt to begin treating it with a topical. There haven’t been enough large studies of the treatments, so there is no standard protocol. But case studies have shown success with topicals such as retinoids, vitamin C, and imiquimod cream, which is an immune response-modifying medication.

Other treatment options may include:

  • Cryotherapy
  • Laser therapy
  • Dermabrasion
  • Curettage, which scrapes the skin surface with a thin, sharp blade
  • Photodynamic therapy

 

Porokeratosis is a noncontagious skin condition that shows up as brown, raised bumps or scaly patches with a distinctive ring around the edge. While the exact cause isn’t fully understood, factors such as genetics, a weakened immune system, and UV exposure play a role. Treatment typically involves prescription topical creams, proper sun protection, and regular monitoring. Persistent or high-risk lesions may require surgery or other more aggressive therapies.

What is disseminated porokeratosis? 

There are two types of porokeratosis that are disseminated: disseminated superficial actinic porokeratosis (DSAP) and disseminated superficial porokeratosis (DSP). DSAP is the most common type of porokeratosis. 

How do you fix porokeratosis?

There is no cure for porokeratosis. Your treatment plan will depend on the severity and type of porokeratosis that you have, but it is likely to involve some sort of topical treatment. 

Is porokeratosis painful?

Not all types of porokeratosis cause pain. It may depend on the location of the skin patches and the friction caused by clothing and shoes. 

Is porokeratosis a rare disease?

Yes, porokeratosis is a rare disease. The exact number of people who have it is unknown. 

Can you freeze porokeratosis?

Yes, cryotherapy — or freezing the skin lesions with liquid nitrogen — is a common porokeratosis treatment option. Talk to your doctor to see if cryotherapy is an option for you.