Ichthyosis describes a group of disorders characterised by persistent scaling of the skin.
Last updated February 2014 by Professor Celia Moss, Consultant Dermatologist, Birmingham Children’s Hospital, Birmingham, UK.
There are several different types of ichthyosis. Some mainly affect the skin, such as:
- ichthyosis vulgaris
- X-linked ichthyosis
- congenital ichthyosiform erythroderma (also known as non-bullous ichthyosiform erythroderma)
- lamellar ichthyosis
- epidermolytic hyperkeratosis (also known as bullous ichthyosiform erythroderma)
- harlequin ichthyosis.
Others are multi-system disorders, affecting other body systems, such as the nervous or immune systems, such as:
- Netherton syndrome
- Sjögren Larsson syndrome
- Refsum disease
- neutral lipid storage disease
- KID syndrome (a rare congenital disorder characterised by keratitis, ichthyosis, and deafness)
- Conradi-Hunermann syndrome.
Scaling varies in severity, from relatively mild scaling in ichthyosis vulgaris to the severe constricting plate-like scale of harlequin ichthyosis. Depending on the condition there may also be redness or blistering.
Ichthyosis is due to a mutation in a gene responsible for a normal skin structure. Each type of ichthyosis is due to a different gene mutation.
A dermatologist will diagnose ichthyosis simply from the appearance of the skin. Diagnosing the precise type of ichthyosis may require referral to other specialists and investigations such as blood tests (for genetic testing) and occasionally skin biopsy (where a small piece of skin is removed for analysis).
There is no cure for ichthyosis but the condition can be alleviated. The mainstay of treatment is to moisturise and exfoliate the skin, to minimise dryness, scaling, cracking and build-up of skin. A variety of moisturisers is available. Steroid creams are not appropriate treatment for ichthyosis. Retinoid drugs such as acitretin are beneficial for some types of ichthyosis but can have serious side effects so their use is restricted to severe cases.
Sometimes additional treatments are required, such as antiseptics or antibiotics for infection, suction clearance of the ear canal for blockage by scales, physiotherapy and night-time splinting to prevent joint contractures. Tight skin may prevent the eyelids from closing fully, so the exposed eye must be protected by lubricants and checked regularly by an ophthalmologist.
The appearance of the skin often attracts unwanted attention and remarks, causing distress to patients of all ages and their families. Counselling and psychological support should be requested if necessary.
Some types of ichthyosis are simply passed from one generation to the next (autosomal dominant, eg ichthyosis vulgaris); X-linked ichthyosis affects only males, while females can be carriers. Most severe types of ichthyosis are inherited as autosomal recessive traits; parents appear unaffected but carry one copy of the mutant gene, while a child receiving two copies of the mutant gene will have ichthyosis. Once the type of ichthyosis has been diagnosed, patients may be referred to a clinical geneticist to discuss the inheritance pattern and risks to future pregnancies.
Prenatal diagnosis is available for most severe types of ichthyosis, using chorionic villus sampling, and requires careful counselling by a clinical geneticist.
Ichthyosis Support Group
The Group is a Registered Charity in England and Wales No. 1142457. It provides information and support to anyone affected by ichthyosis, and offers events and a family conference.
Group details last updated February 2016.