Rare Ichthyoses Factsheet

What is ichthyosis? 

‘Ichthyosis’ is a group of genetic skin conditions characterised by dry, scaly skin.  

There are a number of conditions that as well as having ichthyosis present with other features and some of these very rare forms of ichthyosis are summarised below. 

Sjögren-Larsson syndrome 

This condition is characterised by three features: a) ichthyosis; b) neurological problems which are often severe and c) mild to moderate mental retardation. The neurological problems can cause weakness and partial paralysis in the legs, but often these children learn to walk unaided or with the help of crutches. It is inherited as autosomal recessive affecting one in four children, assuming both parents are carriers. It is caused by an abnormality in a chemical (fatty alcohols) in the skin and nerves. The gene has been found allowing pre-natal diagnosis early in pregnancy. Treatment includes regular skin care, moisturising creams, bath oil, physiotherapy, as well as support from a number of specialists – dermatologist, neurologist and orthopaedic surgeon. Acitretin or neotigason is a retinoid drug taken by mouth which is related to vitamin A and can be helpful for this condition. It needs careful monitoring under hospital supervision. Orthopaedic surgery, such as the release of tightened tendons, is beneficial. 

Conradi-Hünermann syndrome 

In this condition ichthyosis is associated with bone abnormalities and cataracts. X rays of the skeleton in babies shows tiny spots at the growing end of the long bones called stippling, which is characteristic for this condition. The ichthyosis or scaling of the skin is often in lines or swirled patterns. It is inherited as a disorder of the X-chromosome and seen in girls. Treatment is along the same lines as the other more severe ichthyoses. 

Keratitis-ichthyosis-deafness (or KID) syndrome 

This combination is rare and most cases are sporadic with no family history. The skin changes develop in infancy with spiny thickening of the skin, which is prone to becoming infected. They are handicapped by deafness and visual impairment. Treatment is symptomatic and along the same lines as the other more severe ichthyoses. 

Refsums disease 

This ichthyosis is usually not severe and develops later in childhood with fine white scales like ichthyosis vulgaris. The main problem is neurological with progressive weakness and a serious eye condition called retinitis pigmentosa. It is due to an accumulation of a fat chemical called phytanic acid in the skin and nerves. Dietary restriction of phytanic acid, found particularly in green vegetables, is helpful if started at an early age. 

Trichothiodystrophies 

The main features are ichthyosis and short brittle hair. It is due to a deficiency of sulphur, which can be demonstrated in the hair. There are a number of different variations depending on other associated symptoms. These are given the names: IBIDS (ichthyosis, brittle hair, impaired intelligence, decreased fertility and short stature) and PIBIDS which is the same but with photo- (or sun-) sensitivity. Treatment is symptomatic and along the same lines as the other more severe ichthyoses. 

CHILD syndrome 

The acronym child describes a very rare disorder comprising congenital hemidysplasia (under developed) with ichthyosiform erythroderma and unilateral limb defects, mainly skeletal hypoplasia [1]. The skin lesion more often resembles a unilateral inflammatory epidermal naevus (warty birthmark), rather than an ichthyosis. Happle suggested that it is a unique inherited naevus determined by an X-linked dominant mutation, as the female : male ratio is 28 : 1 and skin involvement may occur in Blaschko’s lines.  Over 30 cases have been reported since the 1960s. 

The skin lesions are usually noted in the first days of life as an inflamed, hyperkeratotic (warty), crusted or thickened plaque covering a large area or most of one side of the body, with sharp demarcation at the midline. Linear bands of normal skin on the affected side and of ichthyotic scaly red skin on the ‘normal’ side may occur, and suggest a mosaic somatic mutation. The flexures on the affected side are preferentially involved, and the head is usually spared. The skin lesions may progress in the first year of life and then improve with time. Unilateral alopecia and nail dystrophy may occur. Various other defects, some of which may prove fatal, include congenital heart disease, spina bifida and renal defects. The most common skeletal defect is ipsilateral limb hypoplasia, and calcific stippling of epiphyses (bone growth plates) in infancy has been reported. A sibling of an affected patient had bilateral limited skin disease in the absence of extracutaneous features. Bilateral symmetrical lesions were reported in one patient with a novel NSDHL mutation. The lesions may be mistaken for an epidermal naevus, lichen striatus or linear psoriasis. Cataracts do not occur. 

Genetics. The theory of X-linked dominant inheritance is convincing and explains the apparent lethality in male embryos. The predominantly unilateral and mosaic distribution is attributed to the Lyon effect of random X chromosome inactivation. An early teratogenic insult and syndromes associated with limb reduction defects must be included in the differential diagnosis. 

Treatment. Emollients and keratolytics are helpful. Urea-containing emollient, retinoid therapy and methotrexate have improved the skin lesions in individual patients. 

Moisturising creams and skin treatment  

It is very important that the skin is kept moisturised at all times and that moisturising creams or ointments are applied frequently. Moisturising agents should be perfume-free and without additives to avoid any allergic reactions. The use of bath oils (not bubble bath or soap) is helpful so that bathing does not cause drying or irritation of the skin and soaking in the bath tends to be more beneficial than taking a shower.  

Emollients and keratolytic creams which contain urea, and/or lactic acid (see product’s ingredients label for these) can be useful to remove scales. However these should be avoided if the skin is particularly itchy or red because they may irritate the skin.  

In very severe cases antibiotics can be given to treat secondary infections.  

More specific information on caring for the skin can be found on the Ichthyosis Support Group website at www.ichthyosis.org.uk.  

Personal care 

Scaling and peeling skin, particularly in the most visible areas such as the scalp or face, can be difficult for building self-confidence so individuals may need extra support.  General practitioners need to understand the psychological impact of the condition and provide adequate support to the family. This may require the involvement of other healthcare professionals.  

Further help 

There are a number of online forums about Ichthyosis where individuals can share their experiences and detail their own treatment recommendations. Not everything will work for everyone but these forums are a good place both to receive and offer support. 

Contact the Ichthyosis Support Group for information, advice, details on useful products, and to be connected with other people to share experiences and helpful advice. 

Download The Rare Ichthyoses Factsheet

To find out more about the ISG or become a member please get in touch in one of the following ways: 

By Phone

0800 368 9621

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[email protected] 

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facebook.com/ichthyosissupportgroup 

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