The skin is the largest organ of the human body. There are a number of conditions that can affect the skin. Some of them are common, while others are rare.

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Many people may have experienced eczema or hives, for instance. However, some skin diseases affect far fewer people. Many of these are inherited conditions.

Below, we list 11 rare skin diseases along with their symptoms and possible treatments.

This rare skin condition usually affects children under 4 years old. It is a genetic disorder and has similar symptoms to sarcoidosis.

Symptoms include:

  • joint pain and swelling
  • skin reddening
  • patchy, dark spots on the skin
  • eye inflammation and irritation

There is no cure for Blau syndrome, but it is possible to treat and manage its symptoms. For instance, corticosteroids may help with inflammation.

Actinic prurigo (AP) is a skin condition that causes extreme itching in response to sunlight exposure.

Symptoms include:

  • itchy rash
  • small red papules, plaques, or nodules on the skin
  • weeping and crusting, in some cases

Skin exposed to sunlight frequently exhibits the most severe rash.

AP most often crops up on the face, lips, neck, chest, arms, and hands. It can also cause eye irritation. The condition can also affect places on the body that do not get direct sunlight exposure.

There is no cure for AP. However, people can manage symptoms by limiting their exposure to the sun and protecting themselves when they go outside on very sunny days.

During flare-ups, people can use:

  • topical corticosteroids
  • anti-itch creams
  • antimalarial drugs to help with inflammation

Peeling skin syndrome (PSS) is a rare genetic skin disorder where skin shedding happens at an accelerated rate. The condition can start at birth or early on in childhood.

Factors such as heat and friction may worsen the peeling, which can affect only the extremities or the entire body.

Possible symptoms of PSS include:

  • skin shedding or peeling, usually painless
  • blistering
  • itching
  • skin reddening

Treatment for PSS involves adequate moisturizing of the skin. There is no way to stop skin shedding.

People with argyria experience skin color changes because of a buildup of silver salts in the body. The skin takes on a blue-gray appearance.

It can happen when a person self-medicates with supplements or other substances that contain silver. It can also occur because of occupational exposure to silver, such as in metal alloy manufacturing.

Signs of argyria include:

  • blue-gray skin tone, mostly on parts of the skin that get a lot of exposure
  • hyperpigmented nails
  • whites of the eyes taking on a blue-gray tinge

Argyria is a permanent condition. However, a scientific literature review from 2020 suggests that laser treatment may reduce pigmentation in people with argyria.

Erythropoietic protoporphyria is a metabolic disorder. It happens because of an inherited deficiency of an enzyme called ferrochelatase.

People with this disorder have photosensitive skin — skin that is sensitive to sunlight.

Some symptoms of this skin condition include:

  • skin pain upon exposure to the sun
  • with prolonged exposure, redness and swelling of the skin

Blistering and crusting can also occur, but these symptoms are less common. Over time, the condition can lead to scarring and thickening of the skin.

There is no cure for erythropoietic protoporphyria. People must limit sun exposure to prevent a painful reaction.

Infants born with this rare genetic disease have a waxy skin layer that they shed within a few weeks. Once they shed this layer, the skin beneath is red and scaly.

Other symptoms of the condition are:

  • outward-turning lips and eyelids
  • hair loss
  • lack of eyebrows
  • nail abnormalities
  • breathing problems
  • dry skin
  • thickened skin on the palms and the soles of the feet

There is no cure for the condition. Treatment involves managing symptoms, which may vary from person to person. Moisture and humidity can help keep the skin hydrated.

Infants born with this rare condition have thick, hard plates covering their skin. Harlequin ichthyosis affects only one in 300,000 newborns.

Features of the disease include:

  • skin abnormalities at birth
  • very thick, shiny patches or plates of skin
  • fissures separating these thick plates
  • eyelids turned outward
  • nose, ear, and lip abnormalities
  • extra digits on the hands or feet
  • difficulty regulating body temperature
  • dehydration

There is no cure for this rare disease. Treatment revolves around preventing infection and protecting the delicate skin. Doctors may prescribe antibiotics to prevent and treat infection in the few weeks after birth.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are a rare condition that usually occurs after a person takes a certain medication. Anyone can develop it, but it is much more common in people with HIV.

Medications most often linked to SJS and TEN include:

Scientists do not fully understand the reason for this kind of spontaneous reaction to medication.

Some of the signs of SJS and TEN include:

  • fever
  • sore throat
  • problems swallowing
  • cough and runny nose
  • irritated, red eyes
  • aches and pains
  • painful rash that may appear as:
    • flat red or purple spots
    • blisters
    • target-like
    • diffuse reddening
  • mouth ulcers
  • crusted, red lips
  • diarrhea

The first line of treatment is to stop taking the drug that may have caused the reaction.

People who suspect they have this condition should seek emergency medical treatment.

Epidermolysis bullosa refers to a group of inherited skin conditions that cause blisters and lesions on the skin and mucous membranes.

The blistering usually occurs in places where there is friction. It also appears in response to minor trauma.

There is no cure for epidermolysis bullosa, but people can manage the condition by protecting the skin and avoiding blister formation.

People with chromhidrosis produce colored sweat. It typically starts after a person goes through puberty.

Symptoms include:

  • colored sweat that may be black, green, brown, yellow, or blue
  • a warm feeling of the skin right before producing colored sweat
  • a prickly sensation of the skin

This condition is rare but benign. Doctors can treat it with topical capsaicin cream or botox injections.

Necrobiosis lipoidica is a rash that affects the lower legs and is more common in females. It usually affects people with diabetes but can affect others as well.

The rash may be:

  • localized to the shin area
  • painful or tender
  • oval, round, or irregular in shape

The rash often has a center with prominent blood vessels. It can ulcerate because of minor trauma. Ulcers may lead to infection.

Some treatment options involve topical steroids, steroid injections, or niacinamide. Sometimes, no treatment is necessary.

Some of these conditions are hereditary, which means that people have them from birth or develop them early on in childhood.

People whose skin is bothering them because of a rash or other ailment should consult a dermatologist. Most rashes are not a serious cause for concern.

The American Academy of Dermatology Association recommend that people contact a doctor for a rash if:

  • it affects the entire body
  • they also have a fever
  • the rash happened suddenly and is spreading
  • there is blistering or open sores
  • it is painful
  • there is an infection

Most rare skin conditions have a genetic link, and people inherit them in some way. However, sometimes people may develop a rare skin condition later in life.

People who are worried about their skin health should talk with a dermatologist. If a person feels bothered by something on their skin, it is worth speaking with a healthcare professional to get a proper diagnosis.