History Ichthyosis has existed as long as mankind has existed, and even dogs can
have ichthyosis. It is thought that some individuals of the Merovingian dynasty, and also
Siegfried, the hero in the German medieval Nibelungenlied had
ichthyosis. The first scientific, documented case is of Edward Lambert, who was
introduced to the Royal Society in London on May 16th 1731. His parents
were not affected, but he is described as having Ichthyosis Hystrix.
He married and passed on his condition to six of his offspring, however
his life span was not diminished by his ichthyosis because he was aged
90 when he died in an accident in 1806. Symptoms The characteristic symptom of all the ichthyoses is a dry, thickened
epidermis (outermost layer of the skin) and visible scaling. Some types
of ichthyosis show reddened skin and most people with congenital
ichthyosis cannot sweat. Ichthyosis with blistering (EHK) and ichthyosis
with associated findings (e.g. Netherton's syndrome, Sjögren-Larsson
syndrome) are rare. Cause The skin is alive. It is constantly renewing itself, dying and
shedding. The cuticle consists of several sub-layers and cells are born in the
deepest layer called stratum basale. These cells migrate outward,
flattening and dying as they go and finally arriving at the surface
layer called the corneal layer. The corneal layer consists of thin layers of flat dead cells containing
keratin, a stringy, fibrous protein which reinforces the corneal layer.
Fat is stored between the cells and this makes the skin water-repellent.
The corneal layer also helps to regulate the water balance of the body.
The corneal layer is constantly shedding in microscopically small pieces
and the whole process is called keratinization. This process of
keratinization renews the skin approximately every 4 weeks. In healthy skin, the production of new cells and the shedding is
constant, but with ichthyosis the shedding is disturbed and visible
scales are formed. Proliferation-hyperkeratinization occurs in some of
the ichthyoses where the cells are formed too rapidly whilst in others
the skin's natural shedding process is slowed or inhibited. In X-linked
Ichthyosis and Ichthyosis Vulgaris the skin cells reproduce
at a normal rate but do not shed as quickly, and it is this which
produces a build-up of scales. Effect The skin is the body’s largest organ and therefore ichthyosis affects
the sufferer accordingly. With moderate ichthyosis the affects are
less, and especially in winter the skin is dry, sometimes scaly and
itching may occur. With severe ichthyosis (congenital ichthyosis) more
scales are formed and the symptoms are more extreme. Ichthyosis disturbs the normal function of the skin and because sweating
is affected, the body cannot regulate internal temperature normally and
overheating occurs. It is important to always have water at hand in
the summer and whilst taking exercise. Swimming is often a very
suitable exercise, because of the cool water. With EHK
the skin is very fragile and easily forms blisters. If the soles of the
feet are affected just a short walk may result in sore and aching
blisters. This is an issue for a baby learning to walk. Therapeutic
horseback riding may help by training muscles to find balance and to
learn rhythm without putting pressure on the soles of the feet. Diagnosis A physician can often diagnose ichthyosis just by looking at the skin. In some cases, a blood test or a skin biopsy will be taken to confirm
the diagnosis. A small piece of skin is extracted in a biopsy and
examined under a microscope. Family history is also very useful and most recently genetic testing is
helpful in making a diagnosis. Ichthyosis is not more or less common in any ethnic group. Treatments The routine of skin care is very time consuming, with daily bathing and
moisturising and regular exfoliation of the build up of scales. Treatments take the form of topical application of moisturisers which
include ointments, creams, lotions and emollient oils. Retinoids may be used for some conditions. Careful exposure to sunlight may improve the condition. Types There are several forms of ichthyosis. Most forms are genetic
conditions, which can be divided into two main groups: Noncongenital (vulgar) ichthyosis is not visible at birth; it develops
within the first months after birth. Congenital ichthyosis is present at
the day of birth.

• noncongenital ichthyosis
  • Ichthyosis vulgaris (Autosomal Dominant Ichthyosis vulgaris,
    ADI)
  • X-linked ichthyosis (XRI)
• congenital ichthyosis
  • Ichthyosis lamellaris
  • Bullous Ichthyosis (Epidermolytic hyperkeratosis, EHK)
  • Harlequin Ichthyosis
  • Netherton's syndrome
  • Sjögren-Larsson syndrome
• Ichthyosis acquisita is acquired not inherited, it is a
  manifestation of other diseases.