What are the other Names for this Condition? (Also known as/Synonyms)

• Bullous Ichthyosiform Erythroderma (BIE)
• EHK (Epidermolytic Hyperkeratosis)
• Epidermolytic Hyperkeratosis (EHK)

What is Bullous Ichthyosis? (Definition/Background Information)

• Bullous Ichthyosis is a very uncommon skin disorder that manifests as dry scales, resulting in a rough-dry skin texture. It is a congenital disorder and caused by specific genetic defects in the keratin gene
• Ichthyosis, in general, is of many different types. Some types are congenital and others are acquired. Ichthyosis can also be present as an acquired symptom in other disorders
• There are 5 different types of inherited Ichthyosis disorders that include the following:
  • Ichthyosis Vulgaris; it is the most common form of Ichthyosis
  • Lamellar Ichthyosis, Type 1 to Type 5
  • Epidermolytic Hyperkeratosis (or Bullous Ichthyosis)
  • Congenital Ichthyosiform Erythroderma
  • X-Linked Recessive Ichthyosis
• The pattern and extent of the scales can vary according to the type of Ichthyosis. Depending on the type of Ichthyosis, other symptoms such as involvement of the eyes may be noted
• The diagnosis for Bullous Ichthyosis usually involves a complete medical history assessment, physical examination, and genetic testing
• Once the condition is diagnosed, symptomatic treatment of Bullous Ichthyosis is undertaken, since the condition cannot be cured. This can help prevent complications such as skin infections that occur frequently otherwise
• The prognosis of Bullous Ichthyosis depends on the severity of the signs and symptoms. Individuals with mild signs and symptoms have a better prognosis than those with severe conditions

Who gets Bullous Ichthyosis? (Age and Sex Distribution)

• Bullous Ichthyosis occurs with a general incidence of 1 in 300,000. It is a rare disorder
• The symptoms may occur at birth or may be observed in the neonatal period (first 28 days of life). Generally, the other inherited types occur early in life (usually first 10 years of life) whereas the acquired type can occur later in life
• Bullous Ichthyosis can occur in both males and females; no predilection is noted 
• The condition is seen all over the world; there is no particular geographical restriction or ethnic/racial preference

What are the Risk Factors for Bullous Ichthyosis? (Predisposing Factors)

• In case of inherited Bullous Ichthyosis, a positive family history of Ichthyosis is an important risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Bullous Ichthyosis? (Etiology)

• Bullous Ichthyosis is caused by an abnormality in the development of the part of the skin called  the epidermis. The abnormality occurs during development of the epidermis layer of the skin
• The condition is inherited in an autosomal dominant manner, due to a detective keratin gene. The specific genes affected are the keratin 1 gene and keratin 10 gene (KRT1 and KRT10)
• Bullous Ichthyosis is not a contagious condition. It is caused by a genetic defect, and it cannot be passed on from one individual to another through direct contact

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Bullous Ichthyosis?

The signs and symptoms of Bullous Ichthyosis vary from individual to individual. Some have mild signs and symptoms, while others have severe signs and symptoms. The signs and symptoms of Bullous Ichthyosis may include:

• Blisters on the skin in newborns, which may break to leave behind a red, raw skin surface. Dry scaly skin forms later in life
• The pattern of affected areas depends on the age of the individuals
  • Early-onset Bullous Ichthyosis usually causes blisters
  • Late-onset Bullous Ichthyosis causes thick scales
• The affected areas include the joints and flexural areas (creases of armpits, elbows, and knees)
• Palms and soles may show scaling of skin
• Individuals may have a foul-smelling body odor

Note:

• Many types of Ichthyosis are caused by genetic defects. The signs and symptoms due to a particular genetic defect may vary significantly. This is called variable expression of a genetic defect
• Some types of Ichthyosis may be associated with other diseases such as testicular cancer, sterility in men, malignancy of various parts of the body, heart defects, deafness, hair loss, mental retardation etc. This is NOT the case in Bullous Ichthyosis

How is Bullous Ichthyosis Diagnosed?

It is important to determine the type of Ichthyosis. Many different modalities of testing are used to determine the type of Ichthyosis. However, an accurate diagnosis may not be always possible.

Some of the diagnostic steps for Bullous Ichthyosis may include:

• A through family history and a complete physical examination
• Complete blood count (CBC) test
• Genetic testing of a blood sample for specific types of mutations (in keratin gene) can help confirm a diagnosis. These tests are commercially available
• Ultrasonography may also show excess of amniotic fluid (polyhydramnios), in case of congenital ichthyosiform erythroderma (CIE), to assist in prenatal diagnosis
• Skin biopsy (of the affected skin area) is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis
• Fetal skin biopsy at 19 week gestation will help in diagnosing specific types of congenital Ichthyosis syndromes

A differential diagnosis may be considered by the healthcare provider to rule out other similar conditions. This may include:

• Epidermolysis bullosa
• Lamellar Ichthyosis
• X-Linked Recessive Ichthyosis (XLI)
• Toxic Epidermal Necrosis (TEN) or Steven-Johnson (SJ) syndrome
• Staphylococcal scalded skin syndrome

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Bullous Ichthyosis?

Bullous Ichthyosis can lead to many complications and these may include:

• Dehydration requiring frequent fluid intake
• Painful ulcers
• Infections of the skin requiring frequent medical attention
• Chronic blistering that may get secondarily infected
• Heat intolerance: Skin is a very important organ to maintain the body temperature. Individuals with Ichthyosis have low heat tolerance of the body, resulting in overheating. This may result in heat strokes, which can be a dangerous condition
• Bacterial colonization causes individuals with Bullous Ichthyosis to have a pungent odor
• Individuals with Ichthyosis may have significant psychological issues. Due to abnormal skin, with abnormal scales and odor, these individuals may face social ostracism. This can result in children and adults having low self-esteem and depression

How is Bullous Ichthyosis Treated?

Bullous Ichthyosis is treated symptomatically. Special attention is paid to each individual’s specific condition and needs. There is no cure for the disorder and often a lifelong treatment course is essential.

• Dermatologist’s consultation is very critical in the treatment of Bullous Ichthyosis. An ophthalmologist’s consultation is very important for eye-related abnormalities
• Medications, such as oral retinoid, to decrease scaling of the skin
• Mild keratolytic lotions, containing urea, low concentration salicylic acid, or alpha hydroxy acids as active ingredients can decrease adherence of the abnormal keratin flakes
• Soaking baths, both in plain water and dilute sodium hypochlorite (bleach) can keep skin flexible and lower skin bacterial colonization
• Oral antibiotic treatment may be prescribed for secondary skin infections
• Proper eye care for dry eyes through eye drops help in keeping the dry eye surface moisturized
• Moisturizing creams may be used for dry surface of skin in the affected areas. Reducing exposure can help in decreasing the dryness
• Surgical skin grafts for repair of large areas of severe dry skin
• A social worker or a psychiatric consultation for social issues related to excessive dry skin areas
• Maintain good body hydration status
• Avoiding excessive heat situations, such as outdoor activities in hot sunny days
• Long term treatment of Bullous Ichthyosis is usually necessary in majority of cases

How can Bullous Ichthyosis be Prevented?

Currently, there are no specific methods or guidelines to prevent Bullous Ichthyosis, since it is a genetic condition.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Bullous Ichthyosis
• Reducing sun exposure can help in decreasing skin dryness

What is the Prognosis of Bullous Ichthyosis? (Outcomes/Resolutions)

• The prognosis of Bullous Ichthyosis depends on the severity of the signs and symptoms
• Individuals with severe signs and symptoms have a worse prognosis compared to those with milder signs and symptoms

Additional and Relevant Useful Information for Bullous Ichthyosis:

Numerous conditions can have skin symptoms resulting in dry scaly skin. They include:

• Acrodermatitis enteropathica
• Thyroid disorder causing eye symptoms
• Atopic dermatitis
• Viral infections, such as caused by herpes zoster virus, and HIV
• Kaposi sarcoma in patients with AIDS
• Retinitis pigmentosa
• Acute leukemia
• Psoriasis
• Sarcoidosis