Millions of Americans live with at least one skin condition. You’re probably familiar with the more common ones like acne, eczema, and rosacea. In fact, there’s a good chance you may have one of them yourself.

There’s also a wide range of rarer skin conditions that you may not know about. They can range from mild to life threatening. In some cases, they can affect the quality of life of those who develop them.

Read on for a brief overview of some of these lesser-known conditions.

Hidradenitis suppurativa (HS) is a chronic inflammatory condition that causes lesions to form on parts of the body where skin touches skin. The most common areas for breakouts to occur are the:

  • underarms
  • groin
  • buttocks
  • upper thighs
  • breasts

Although the cause of HS is unknown, it’s likely that hormones play a role in its development since it typically begins around puberty.

Up to 2 percent of the population has the condition. It’s most common in people who are overweight or smoke. Women are over three times more likely to have HS than men.

Genetics and the immune system are believed to be factors in who develops the disease.

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People with hidradenitis suppurativa are at an increased risk for certain conditions (or comorbidities), such as:

  • acne
  • inflammatory bowel disease (IBD)
  • follicular occlusion tetrad (a group of inflammatory skin conditions that includes acne conglobata, dissecting cellulitis of the scalp, and pilonidal sinus disease)
  • metabolic syndrome
  • polycystic ovarian syndrome (PCOS)
  • squamous cell carcinoma of the affected skin
  • type 2 diabetes

The initial symptoms of HS are breakouts that look like pimples or boils. These breakouts either stay on the skin or clear and then reappear.

If left untreated, more severe symptoms can occur, such as scarring, infection, and breakouts that rupture and emit a foul-smelling fluid.

There’s currently no cure for HS, but a number of treatment options are available to help manage symptoms. These include:

  • topical ointments,
  • anti-inflammatory drugs, including injectable biologics
  • hormone therapy

Surgery may be considered for more severe cases.

Inverse psoriasis is sometimes called intertriginous psoriasis. Similar to HS, this condition creates red lesions on parts of the body where skin touches skin. These lesions aren’t boil-like. They appear to be smooth and shiny.

Many people with inverse psoriasis also have at least one other type of psoriasis somewhere else on their body. Experts aren’t exactly sure what causes psoriasis, but genetics and the immune system are key contributing factors.

Psoriasis affects about 3 percent of people around the world, and 3 to 7 percent of people with psoriasis have inverse psoriasis.

Since the skin in high-friction areas of the body tends to be sensitive, treating the condition can be difficult. Steroid creams and topical ointments may be effective but often cause painful irritation if overused.

People living with more severe cases of inverse psoriasis may also need ultraviolet B (UVB) light therapy or injectable biologics to manage their condition.

Harlequin ichthyosis is a rare genetic disorder that causes children to be born with hard, thick skin that forms diamond-shaped scales across their bodies.

These plates, separated by deep cracks, can affect the shape of their eyelids, mouth, nose, and ears. They can also restrict movement of the limbs and chest.

Around 200 cases have been reported worldwide. The condition is caused by a mutation in the ABCA12 gene, which allows the body to make a protein essential for the normal development of skin cells.

The mutation prevents the transportation of lipids to the skin’s top layer and results in the scale-like plates. The plates make it more difficult to:

  • manage water loss
  • regulate body temperature
  • fight infection

Harlequin ichthyosis is an autosomal recessive disorder that’s passed on through mutated genes, one from each parent.

Since the biological carriers rarely exhibit symptoms, genetic testing can identify changes in genes and determine your chances of developing or passing on any genetic disorders.

The most common treatment for harlequin ichthyosis is a strict regimen of skin-softening emollients and skin-repairing moisturizers. In severe cases, oral retinoids may also be used.

Morgellons disease is a rare condition in which small fibers and particles emerge from skin sores, creating the sensation that something is crawling on the skin.

Little is known about the condition, but it affects over 14,000 families, according to the Morgellons Research Foundation.

Morgellons is most prevalent in middle-aged white women. It’s also closely associated with Lyme disease.

Some doctors believe it’s a psychological issue since its symptoms are similar to those of a mental health disorder called delusional infestation.

Symptoms are painful but not life threatening. Common symptoms include:

  • itchy skin rashes or sores
  • black fibrous material in and on the skin
  • fatigue
  • anxiety
  • depression

Lesions affect one specific area: the head, trunk, or extremities.

Since Morgellons disease is still not fully understood, there’s no standard treatment option.

People with the disease are typically advised to keep in close contact with their healthcare team and seek treatment for symptoms, such as anxiety and depression.

Elastoderma is a rare condition marked by increased looseness of the skin on specific areas of the body. This causes the skin to sag or hang down in loose folds.

It can occur on any part of the body, but the neck and the extremities, especially around the elbows and knees, are the most commonly affected areas.

Fewer than 1 in 1,000,000 people worldwide have the condition. The exact cause of elastoderma is unknown. It’s thought to be the result of the overproduction of elastin, a protein that gives structural support to organs and tissues.

There’s no cure or standard treatment for elastoderma. Some people will undergo surgery to remove the affected area, but the loose skin often returns following the operation.

Pilonidal sinus disease results in small holes or tunnels at the base or crease of the buttocks. Symptoms aren’t always obvious, so most people don’t seek treatment, or even notice the condition, until problems arise.

It develops when hair between the buttocks rubs together. The resulting friction and pressure push the hair inward, causing it to become ingrown.

This mild condition is seen in 10 to 26 people out of every 100,000. Most people with this condition are between ages 15 and 30, and the incidence in men is twice the incidence in women.

It often affects people working in jobs that require long hours sitting. It’s also a comorbidity of hidradenitis suppurativa (HS).

Treatment for an infected pilonidal sinus depends on a few factors:

  • your symptoms
  • the size of the abscess
  • whether it’s a first-time or a reoccurring infection

Treatment is usually invasive and involves draining the affected pilonidal sinus of any visible pus. Antibiotics, hot compresses, and topical ointments are often used as well.

If you’re one of the 40 percent of people with the condition who have recurring abscesses, be sure to talk with your doctor about additional surgical options.

The National Institutes of Health (NIH) classifies pemphigus as a group of autoimmune diseases that causes your immune system to attack healthy epidermal cells. The epidermis is the skin’s top layer.

As in HS, lesions or blisters appear where skin naturally touches or rubs together. They also appear in or on the:

  • mouth
  • throat
  • eyes
  • nose
  • genital areas

Most people with pemphigus have a type known as pemphigus vulgaris. It occurs in 0.1 to 2.7 people out of every 100,000.

Pemphigus vegetans, a variant of pemphigus vulgaris, accounts for 1 to 2 percent of pemphigus cases worldwide.

Pemphigus vegetans can be fatal if left untreated. Treatment focuses on getting rid of the lesions or blisters and keeping them from coming back.

Corticosteroids, or any other steroids that lower inflammation, are commonly the first line of defense. Beyond that, you can have surgery to extract the lesions or blisters, all while making sure to cleanse and dress the area daily.

Remedies for the mouth and throat include medicated mouthwash or clobetasol, a corticosteroid and ointment used to treat oral conditions.

Crohn’s disease is an inflammatory bowel disease (IBD) that affects the gastrointestinal tract.

Approximately 780,000 Americans are living with it. There are around 38,000 new cases each year. Researchers suspect that genetics, the immune system, and the environment play a role in the development of Crohn’s.

Between 20 and 33 percent of people with Crohn’s experience lesions on the skin as a result of the disease. This is known as a cutaneous outbreak.

Cutaneous lesions look similar to genital warts and develop after the bowel disease has manifested on the skin or another organ outside the intestinal tract. This includes the eyes, liver, and gallbladder. It can affect the joints as well.

There’s no cure for Crohn’s.

Surgery is the go-to treatment option for cutaneous lesions. If your Crohn’s disease and lesions have metastasized, or spread, then they can become painful and lead to fatal complications. Few treatment options are currently available for this stage.

Sneddon-Wilkinson disease is a condition in which lesions of pus crop up on the skin in clusters. It’s also known as subcorneal pustular dermatosis (SPD).

Experts aren’t sure what causes it. Rare and often misdiagnosed, the disease typically affects people over age 40, especially women. As such, its exact prevalence is unknown.

Just like in HS, soft, pus-filled bumps form between skin that rubs together a lot. The cutaneous lesions develop on the torso, between skin folds, and in the genital area. They “explode” due to friction.

An itching or burning sensation may accompany this popping of the lesions. Those sensations are followed by scaling skin and discoloration. Though chronic and painful, this skin condition isn’t fatal.

The treatment of choice for this disease is the antibiotic dapsone, with a 50 to 200 milligram (mg) dose administered orally each day.

Inverse lichen planus pigmentosus is an inflammatory condition that causes discoloration and itchy bumps where skin folds.

Mostly affecting people from Asia, only around 20 cases have been documented worldwide. No one knows what causes it.

Flat lesions, or macules, of discolored skin form in small clusters. They don’t usually contain pus, but they sometimes can. Some people’s skin clears up naturally over time, while others may have symptoms for years.

This condition is moderate, not fatal, and can be treated with a topical cream. Corticosteroids are the go-to treatment options for healing and can even help with pigmentation in some cases.

Dowling-Degos disease is a genetic disorder that causes darkened skin, particularly in places that fold, like the armpit, groin, and joint areas.

Although less common, pigment changes can also affect the neck, hands, face, and scalp.

Most of the lesions are small and look like blackheads, but red spots resembling acne can develop around the mouth.

The lesions can also appear as fluid-filled bumps on the scalp. Itching and burning sensations can occur.

Just like HS, skin changes occur in late childhood or early adolescence.

However, some people don’t have any outbreaks until adulthood. Dowling-Degos isn’t life threatening, though people with the disease can experience distress and anxiety.

No cure currently exists for this disease. Treatments from laser therapy to topical steroids to retinoids have been used, but results vary, and nothing has been reliably effective.

If you’re dealing with a skin condition, listen to your body and take any symptoms seriously.

Talk to your doctor. If needed, they can refer you to a dermatologist.

A dermatologist can help you get a diagnosis and determine the best treatment options for your particular issues.