10 Rare Skin Diseases

Skin conditions are common among people of all ages. Some skin diseases such as keratosis pilaris or psoriasis affect millions of Americans each year. Typically, skin disorders are easy to treat or are so mild that they require no treatment at all. There are, however, some skin conditions that are so rare and severe that they require specialized medical treatment. The following 10 skin diseases are so rare that you may have never heard of them at all.

1. Argyria

Argyria is a rare skin disorder that causes the skin to change color into a blue or grayish hue. The cause can be attributed to overexposure to silver. If a person ingests a large dose of silver or is exposed to small amounts of silver for a prolonged period, silver particles can deposit in the skin and stain the skin and mucous membranes bluish-gray or slate-gray.

The disease is not life-threatening, but the discoloration of the skin can pose challenges in day-to-day life. The pigmentation is permanent and almost untreatable. The prevalence of argyria is unknown.

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Symptoms

The main symptom of argyria is blue-gray, metallic, or slate-gray skin. This condition usually begins with a gray-brown staining of the gums that later progress to involve large areas of the skin.

Other symptoms include:

• The fingernails, conjunctival membranes, and mucous membranes may become hyperpigmented (when patches of skin becomes darker compared to the rest)
• Hyperpigmentation is most pronounced in sun-exposed areas such as the face (particularly forehead and nose), neck, arms, and hands

Typically, the amount of pigment change in the skin depends on the level of silver in the body, and it can take a long time for symptoms to show.

Risk Factors

The biggest risk factor is silver abundance in the body. Exposure to silver can take place through occupational exposure like workers involved in silver mining, taking medications with silver salts such as eye drops, using colloidal silver supplements like those for arthritis and diabetes, and during certain surgical and dental procedures involving silver sutures and silver dental fillings.

Treatment

There is no cure for Argyria, but some treatment options are available for those with the disorder. To help lessen the skin pigmentation, using a 5% hydroquinone treatment could help reduce the amount of silver in the skin, making it look less blue or gray. Laser therapy has also been explored as a viable option for the treatment of the disease.

2. Morgellons

Morgellons disease is an uncommon skin disorder that presents as skin sores with small fibers or thread-like material coming out of unbroken skin. The skin condition causes a person to feel as though there are insects crawling on top or underneath their skin near the infected area. Morgellons is often mistaken as a psychiatric disorder.

The prevalence of Morgellons disease is 3.65 cases per 100,000 people. These data were collected by the Centers for Disease Control and Prevention (CDC) during a study with 3.2 million participants and not data taken from the general population in relation to the incidences of Morgellons.

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Symptoms

The main symptoms of Morgellons is a skin rash with sores that have thread-like fibers of various colors coming out of the skin and a biting and crawling sensation.

Morgellons can cause a wide variety of symptoms, including:

• Intense itching in the affected area
• Visual disturbances
• Tinnitus
• Painful skin ulcers
• Irregular heart rate
• High pulse rate
• Unexplained shortness of breath
• Coughing
• Chronic fatigue
• Difficulty concentrating
• Short-term memory loss
• Musculoskeletal pain
• Fibromyalgia

Risk Factors

It's unclear what the exact cause of this skin disorder is. Research has found that Morgellons disease could actually be a tick-borne illness and is associated with Lyme disease. The Morgellons Research Foundation has identified an association with three more bacterial pathogens: Chlamydophila pneumonia, Babesia species, and Borrelia species. The number of cases related to infection is small, however, and there is no evidence that these bacteria directly cause Morgellons disease. A study by the CDC concluded that the fibers were mainly derived from fabric, such as cotton, and that the illness was associated with significantly reduced health-related quality of life.

Treatment

There are typically two different courses of treatment, depending on what the doctor thinks caused the skin disorder. For those that suspect an infection, such as a bacterial infection caused by a tick bite, treatment will typically be done with a round of antibiotics. Morgellons may also be treated with antipsychotic medications.

3. Erythropoietic Protoporphyria

Erythropoietic protoporphyria (EPP) is a skin disorder caused by genetic mutations that cause a deficiency of enzyme protoporphyrin IX. It results in a buildup of protoporphyrin proteins, making the skin to become highly vulnerable to sunlight exposure. It is thought that it occurs in only one in 75,000 to one in 200,000 people in Europe. The risk of developing EPP is approximately one in 10 for the offspring of an affected parent.

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Symptoms

EPP causes skin pain on exposure to sunlight, most often on the tops of the hands and feet, face, and ears. Pain can be severe and last days after sun exposure. Visible changes are mild in most cases. Other symptoms that can occur after being out in the sun in people with EPP include:

• Redness
• Swelling
• Blistering
• Crusting

The symptoms of EPP tend to go away within one day and don’t generally lead to permanent damage. Symptoms are worse in summer and sunny climates. Over the years, the skin on the backs of the hands and cheeks can have some thickening with subtle pitted scarring.

People with EPP are also at a heightened risk of developing liver damage because of the high amounts of the protoporphyrin protein in their blood.

Risk Factors

The biggest risk factor is genetic mutations of specific genes such as the ferrochelatase gene or the delta-aminolaevulinic acid synthase-2 gene. These mutations are inherited. Children and infants are found to develop symptoms early on in life when exposed to sunlight.

In very rare instances, EPP has been reported to have been caused by myelodysplasia or myeloid leukaemia.

Treatment

There is no cure for EPP, so treatment is usually focused on symptom control. Narrowband UVB phototherapy increases melanin content in the skin and induces skin thickening so to provide some level of protection from the sun. Oral antioxidants such as beta-carotene, Polypodium leucotomas extract, warfarin, and N-acetyl cysteine have been used, but are not supported by evidence.

Iron supplementation should be avoided as iron can increase photosensitivity in EPP. Afamelanotide has been reported to be effective for EPP. It is approved for the treatment of EPP under orphan drug status. People with EPP who also have liver disease require specialist medical treatment and possibly a liver transplant.

4. Harlequin Ichthyosis

Harlequin ichthyosis is a genetic disorder characterized by the thickening of the skin over most of the body at birth. The diamond-shaped plates that form over the skin are separated by cracks, and can affect the eyelids, mouth, ears, nose, and cause limited movement in the arms and legs. In serious cases, movement of the chest can be limited, which can lead to issues with breathing and respiratory failure. The skin abnormalities associated with harlequin ichthyosis make it more difficult for affected infants to control water loss, regulate their body temperature, and fight infections. The condition affects one in every 500,000 babies born every year in the United States.

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Symptoms

People with this skin disorder have severely thickened skin with large, shiny plates of hyperkeratotic (thickening of the outer layer of the skin) scale and deep erythematous (red) fissures separate the scales.

Other symptoms include:

• Severe ectropion (eyelid turns outwards)
• Poorly developed nose, obstructed nostrils
• Poorly developed, flattened, or absent ears
• External auditory canal may be obstructed by scale
• Eclabium (lips turn outwards)
• Hypoplasia (underdevelopment of tissues or organs) and extra fingers and toes

Risk Factors

Harlequin ichthyosis is passed down through autosomal recessive genes, so the biggest risk factor is being born from both parents who have the affected gene. The likelihood of having a rare skin disorder is 25% if both parents pass down the gene. If only one parent has the gene, it’s unlikely that the condition will develop. The person will, however, become a carrier, and it can still be passed down to future children.

Treatment

There is no cure for this skin disorder, so treatment focuses on protecting the skin and preventing infections. The thick plate-like outer layer of skin eventually splits and peels at birth, leaving the vulnerable inner layers of the skin exposed. Antibiotic treatment is needed to prevent or treat infections at this time.

Softening emollients, especially those containing urea, salicylic acid, or alpha hydroxy acids, are particularly effective when applied after bathing while the skin is still moist. These products work to keep the skin moisturised and pliable while preventing the cracking and fissuring that can lead to secondary bacterial infection. Early treatment with oral retinoids has also been shown to heal skin fissures, soften or resolve plate-like scales, and improve overall survival.

5. Ichthyosis Vulgaris

Ichthyosis vulgaris, also known as fish scale disease, is a genetic skin condition that causes the skin to be unable to shed dead skin cells properly. Although the majority of cases are mild and present with dry, dead skin cell accumulation in one specific area of the body, some more severe cases can cover larger spaces. It typically occurs in one in every 250 people, and accounts for close to 95% of all ichthyosis cases.

Symptoms

Fish scale disease can be found on any part of the body, and symptoms are less severe in a warm, humid climate. Symptoms often appear after about two months of birth and usually before the age of 5. Symptoms may worsen up to puberty, and sometimes improve with age.

The main symptoms include:

• Chapping of palms and soles
• Keratosis pilaris
• Hyperlinearity (pronounced skin lines) of palms and soles

Atopic dermatitis is present in 50% of people with ichthyosis vulgaris (and 8% of those with atopic eczema have the features of ichthyosis vulgaris). When atopic dermatitis is associated with severe ichthyosis vulgaris, the dermatitis tends to be early in onset, severe, and more likely to persist into adulthood. There is also an increased risk of asthma, rhinitis, and food allergy.

Risk Factors 

The main risk factor is being born to one or both parents who have the gene. Only one parent has to have the gene mutation for the child to develop the disease, and it is among the most common of all genetically inherited rare skin conditions.

Adults can also develop the condition if they have cancer, kidney failure, or thyroid disease. It has also been found in people on specific medications.  

Treatment

Since there is no cure for fish scale disease, treatment options are designed to help cope with and manage the disease. Treatments include:

• Exfoliation
• Regular application of lotions with propylene glycol
• Using a humidifier
• Bathe in salt water
• Apply creams or lotions containing salicylic acid, glycolic acid, lactic acid, or urea to exfoliate and moisturise skin. These may irritate active eczema
• Oral retinoids for severe cases

Tips to help manage this condition:

• Apply lotions and creams to damp skin to trap in the moisture (within three minutes of showering/bathing)
• Lotion and creams can be kept under occlusion for one or two hours with a cling-film wrap to enhance skin hydration
• Gently rub a pumice stone on wet skin to help remove thickened crusty skin
• Brush washed hair to remove scales from scalp

6. Elastoderma

Elastoderma is a rare skin disorder that causes extreme looseness in the skin. It can affect any area of the body, but is most typically found on the skin of the neck, elbows, and knees. The cause of the condition is unknown, and it often occurs in people without a family history of the disorder.

Symptoms

The main symptom of elastoderma is loose skin that sags or hangs in folds. The skin is not stretchy and can often appear wrinkled.

Other symptoms include:

• A lack of recoil of the skin, or the skin tissue’s inability to take on its original shape after being deformed
• Skin nodules
• Skin papules
• Increase sensitivity to sound, taste, smell, or touch (hyperesthesia)

Most people with the skin condition will have one or more symptoms. Eczema and bacterial infections on the upper layer of the skin have also been found in those with elastoderma.

Risk Factors

The cause of elastoderma is largely unknown. It is thought to occur when there is an over-production of elastin in a specific area of skin. Elastin is a protein that is a vital component of skin and other connective tissues throughout the body. It is not clear what causes this increase in elastin in people with this condition.

Treatment

There is no known cure for elastoderma. Some cases have been treated with surgical excision (removal of affected skin), but hyperlaxity of skin often returns following the surgery.

7. Interstitial Granulomatous Dermatitis

Interstitial granulomatous dermatitis (IGD) is a rare skin disorder that presents as a particular pattern of inflammation on the skin, typically described as the rope sign. It is often found in people with autoimmune disorders, and is typically found in early childhood cases of Blau syndrome. IGD often occurs alongside other autoimmune diseases, mainly rheumatoid arthritis. It’s thought that only 53 cases were reported in 2019.

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Symptoms

The main symptoms of IGD is an inflamed rash, but there are also other symptoms, including:

• Red or skin-coloured patches, papules, and plaques
• Round, annular or cord-like lesions 
• Lesions wax and wane, and may vary in size and shape over days to months
• Mild itch or burning sensation
• The lesions tend to be symmetrically distributed on the trunk, but proximal limbs may also be affected

This condition is most commonly found in middle-aged women.

Risk Factors

The exact cause of IGD is unknown, but this condition has been associated with other autoimmune diseases. Research has suggested that it is a cutaneous form of rheumatoid arthritis.

Other conditions that have been linked to IGD include:

• Other forms of arthritis
• Lupus erythematosus
• Antiphospholipid syndrome
• Churg-Strauss syndrome
• Thyroiditis
• Vitiligo

IGD has also been associated with some forms of cancer including leukemia, lymphoma, breast cancer, hyposquamous cell carcinoma, and endometrial neoplasia.

Various medications, particularly calcium channel blockers, lipid-lowering agents, angiotensin-converting enzyme inhibitors, antihistamines, anticonvulsants, and antidepressants have been associated with IGD. Anti-TNF agents such as etanercept, infliximab, and adalimumab are also linked to IGD. 

Treatment

Treatment options for the disease are typically topical steroids or hydroxychloroquine. A case report found that IGD associated with RA was successfully treated with etanercept, which resolved the skin lesions, suggesting that anti-TNF antibodies may be clinically effective for the treatment of IGD.

8. Pemphigus

Pemphigus is an autoimmune skin disease that causes blisters and sores on the skin, in the mouth or throat, or on the genitals. The type of pemphigus depends on where the blisters form, and some are fatal if left untreated. Older adults tend to have this condition, but it can affect people at any age. Research has found that the prevalence of pemphigus is quite low in the United States at only 5.2 cases per 100,000 adults. The prevalence increases with age, and both men and women were affected equally.

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Symptoms

The main symptom of pemphigus is blisters on the skin that rupture and become open sores. Blisters can appear suddenly and spread, and can linger for years. Sores heal slowly, and when they heal, they turn into a dark spot.

Pemphigus vulgaris (70% of all pemphigus cases) begins in the mouth and then occurs on the skin or genital area. Pemphigus foliaceus affects only the skin and often develops on the face, scalp, and upper body. There is also drug-induced pemphigus, which is. a result of taking certain medications.

Other symptoms of pemphigus can include:

• Burning
• Nail problems
• Pain
• Fatigue
• Weakness
• Light sensitivity
• Eye problems

Risk Factors

Pemphigus is more common in people of Jewish or Mediterranean descent. Other factors that may increase a person's chance of pemphigus include:

• Family history of pemphigus
• A history of autoimmune diseases, such as myasthenia gravis , systemic lupus erythematosus, or thymoma
• Regular use of certain medications: Chelating agents, such as penicillamine, ACE inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, antibiotics, such as penicillin, anti-seizure medications, such as phenobarbital, and thiols

Treatment

There is no cure for pemphigus, but there are some treatment options to help control the condition and prevent infection of the blisters.

If the condition is caused by regular use of a medication, stopping the course of medication treatment can be enough to help recovery. Otherwise, treatment is typically through medication, wound care, and lifestyle changes.

The wounds are treated similarly to severe burns. They will be cleaned and protected from further contamination. Antibiotic medications will also be applied to the wounds to prevent infections.

Some medications used to help control symptoms include:

• Corticosteroids
• Topical steroids
• Immunosuppressive medications
• Antibiotics
• Medicated mouthwash
• IV immunoglobulin

Soft diets may help until the lesions heal. Some foods may trigger the onset of more sores, including garlic, onions, and leeks. Also avoid foods that can cause irritation in the mouth like foods that are high in acids, spicy, or hard.

9. Hidradenitis Suppurativa

Hidradenitis suppurativa is a chronic inflammatory disease that causes small, painful bumps on many parts of the body, including the underarms, groin, buttocks, upper thighs, and breasts. The condition typically occurs around puberty. It has a prevalence of 88 cases per 100,000 people in the United States. It is three times more common in women than in men. This condition is also common in people between 18 and 49 years old.

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Symptoms

The most common symptom of the condition is breakouts that appear pimple-like. Other symptoms include:

• Painful firm papules and nodules
• Pustules, fluctuant pseudocysts, and abscesses
• Draining sinuses linking inflammatory lesions
• Hypertrophic and atrophic scars.

The lesions tend to persist for weeks or months, and heal very slowly. Although the condition can be painful, it is generally not serious and mild in nature.

Risk Factors

The cause for the condition is relatively unknown. Some experts believe that it could be linked to genetics, issues within the immune function, and hormones. Although "hidradenitis" implies an inflammatory disorder of sweat glands, research has shown that hidradenitis suppurativa is an autoinflammatory syndrome. 

Associations and risk factors include:

• Family history of hidradenitis suppurativa
• Obesity and insulin resistance (metabolic syndrome)
• Smoking
• African ethnicity
• Follicular occlusion syndrome
• Inflammatory bowel disease, particularly Crohn's disease
• Other skin disorders, including psoriasis, acne, hirsutism
• Comorbidities like hypertension, diabetes mellitus, dyslipidaemia, thyroid disorders, arthropathies, polycystic ovary syndrome, adverse cardiovascular outcomes
• Drugs like lithium, sirolimus, biologics
• Syndromes like PAPA syndrome, PASH syndrome, and PAPASH syndrome

Treatment

There are two main treatment options for Hidradenitis suppurativa: medication and surgery. Specific medications used include:

• Antibiotics creams
• Oral or injectable antibiotics
• Pain medications, both over the counter and prescription strength

If medications do not work, then surgical options can be explored for treatment, including:

• Tissue removal surgery
• Nodule removal
• Electrosurgery to remove damaged tissue
• Laser therapy
• Surgical removal of all affected skin

10. Acral Peeling Skin Syndrome

Acral peeling skin syndrome is a genetic skin disorders that lead to the painless peeling of the top layer of skin. "Acral" refers to the fact that the peeling is most apparent on the hands and feet, although peeling may also occur on the arms and legs. It is usually present at birth, but can appear later in childhood or in early adulthood. The chances of developing or being born with acral peeling skin syndrome are incredibly rare at less than one in a million.

Symptoms

The main symptom of acral peeling skin syndrome is excessive painless skin peeling on the hands and feet. Occasionally, peeling may also occur on the arms and legs. The peeling is made worse by heat, humidity, and other forms of moisture and friction.

Other symptoms may include:

• Blistering skin
• Fragile skin
• Itching
• Redness
• Hair that can be plucked easier than what is typical
• Short stature

The affected areas typically heal without scarring. Acral peeling skin syndrome is not associated with any other health problems, and generally doesn't significantly impair quality of life.

Risk Factors

Acral peeling skin syndrome is caused by a mutation in the TGM5 gene, which provides instructions for making an enzyme called transglutaminase 5, a component of the outer layer of skin. TGM5 gene mutations reduce the production of transglutaminase 5, which allows the outermost cells of the epidermis to separate easily from the underlying skin and peel off. This peeling is most noticeable on the hands and feet because these areas are more frequently exposed to moisture and friction.

The biggest risk factor is being born to both parents with mutations in the specific gene that causes the disorder.

Treatment

There is no cure for acral peeling skin syndrome. Treatment is centered on preventing skin damage and addressing symptoms as they occur. The first line of treatment for peeling skin syndrome includes skin-softening ointments and creams to reduce skin peeling. Typically, the best time to apply creams is when the skin is moist following a bath. The preferred ointments include Vaseline or plain petroleum jelly as other types such as corticosteroids and retinoids have shown no efficacy in the treatment of the condition and can even cause adverse reactions.

If blister develop, they may be lanced with a sterile needle. Light dressings should be applied to prevent infection.