Ichthyosis is a generic term that includes numerous forms of this illness. To this day, 28 different forms have been listed. Ichthyosis is a chronic disease, most of the time of a genetic origin, for which the prevalence depends strongly on the different forms of the illness.
What is ichthyosis?
The most common form is the ichthyosis vulgaris, or vulgar ichthyosis. It is the most frequent transmitted skin condition, and its transmission is generally done according to the autosomal semi-dominant trait (if only one chromosome is affected, the illness will have a light form, if both chromosomes have the mutated allele, the person will generally suffer from a moderate to severe form of the illness). The disease can express itself with different levels of severity, some persons suffering from ichthyosis having not been diagnosed, but are simply considered as having dry skin. This constitutes the huge majority of ichthyosis cases (95% according to the sources) and it is estimated to touch 1 out of 250 births (Wells RS, Kerr CB. Br Med J 1966 ; 1 : 947-50).
The genetic causes of the illness are often about the mutation of the gene coding the profilaggrin, a protein produced in the stratum granulosum, and which, once yielded in multiple filaggrin monomers, is responsible for the aggregation of keratin filaments in the dermis. The mutation of genes coding the profilaggrin leads to a defect in the keratinisation of the skin cells.
The second most frequent form of ichthyosis is the X-linked ichthyosis, with an estimation of its prevalence between 1/200 000 and 1/600 000, and because of its mode of transmission, this form affects almost exclusively men. In this form of ichthyosis, the illness is associated with disorder of the metabolism of the lipids of the skin, which leads to a disturbance of the regulation cycle of the stratum corneum, with a reduction of the flaking of skin cells associated with a hyperkeratosis.
Other forms of ichthyosis exist, and a certain number of them are regrouped under the term of Autosomal Recessive Congenital Ichthyosis (or ARCI). It is in this group that the most severe forms of the illness can be found.
- Lamellar ichthyosis is the most common form of autosomal recessive congenital ichthyosis. Its prevalence is estimated between 1/100 000 and 1/1 000 000. At birth, newborns are often covered in an envelope called the collodion, which disappears a few weeks after birth. The genetic causes of lamellar ichthyosis are multiple, and several genes are associated with this disease.
- Congenital ichthyosiform erythroderma has a prevalence between 1/200 000 and 1/ 1 000 000. As for lamellar ichthyosis, the genetic causes are numerous, and often these two forms have a similar profile, with patients presenting intermediate forms between these two illnesses.
- The form of ichthytosis which has the less favourable prognostic is the Harlequin-type ichthyosis, with a prevalence estimated at 1/1 000 000. In this case, the whole skin is affected by an important hyperkeratosis, and the newborn is wrapped in a collodion membrane, which limits his movements and stretches his faces. Babies suffering from Harlequin-type ichthyosis are particularly fragile at birth, because of a higher risk of infections, respiratory disorder, problems of thermal regulation, and feeding difficulties. The genetic alterations responsible for this form of ichthyosis modify the cellular mechanisms which results in a dysfunction of the lipid barrier.
How does ichthyosis manifest itself?
Ichthyosis, or rather the different forms of ichthyosis, have in common an important dryness of the skin, which is accompanied by an excessive presence of scales, or dead skin. The aspect of these scales, and other manifestations of the illness, are characteristic of the different forms of ichthyosis. For example, for lamellar ichthyosis, the scales are big, dark, and shaped in patches, and for the congenital ichthyosiform erythroderma, the scales are thinner and white, and the patient presents a widespread rash (very red skin).
Other complications can by associated, like eye problems, hearing problems, nail dystrophy, alopecia, palmar-plantar keratoderma, growth retardation, deformation of the extremities… These symptoms are often linked to the different forms of the illness.
What treatments for ichthyosis?
Persons suffering from ichthyosis have an intense daily need for an emollient. It is necessary to hydrate and soften the skin with moistening or emollient products. This can be associated with keratolytic skincare (urea or lactic acid for example).
For certain forms of ichthyosis, systemic retinoids can be a possible oral treatment.
How to relieve ichthyosis?
Persons suffering from ichthyosis have a strong need for moisturising their skin every day. The Hydrating Gel Plus HS is a good solution for this. Indeed, it is based on a patented technology which brings: 40% of moisturising agents and more than 20% of glycerine with a reinforced action of the bisabolol, a soothing agent derived from camomile. It contains only 8 ingredients, thus minimising risks of unwanted reactions for sensitive skins, as well as 0% paraben, 0% silicone (dimethicone), 0% mineral oil, 0% fragrance, 0% EDTA.
Its innovating structure allows for a liberation of glycerine on a long-term basis, to maximise its moistening action while avoiding skin dryness.
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