Definition
The term ichthyosis is used to indicate a series of cutaneous affections called "genodermatosis", that is genetic disorders whose effects appear on the skin.
The term "ichthyosis" derives from the Greek word " Iχτυς", whose meaning is "fish" and indicates the typical scaly appearance that the skin of patients affected by these diseases takes.
Classification
The ichthyosis is not only a disease in itself, but often it is related to other diseases and can be the cause or the consequence; the classification of the various types of ichthyosis is problematic, precisely because the disease has various facets.
A first major classification is that which divides the different types of ichthyosis into hereditary forms and acquired forms .
The hereditary forms, naturally, are present since birth, since the genetic alterations are transmitted by the parents.
The acquired forms, on the other hand, appear in adulthood, usually in association with other pathologies of various origins and nature, such as, for example, tumors (lymphomas, lung, liver, breast or kidney cancer, etc.), Crohn's disease, diseases of the thyroid gland or AIDS.
However, in general, ichthyosis is divided into categories based on the resulting clinical picture . In this regard, we can distinguish:
- The ichthyosis linked to the X chromosome;
- Lamellar ichthyosis;
- Vulgar ichthyosis;
- Epidermolytic hyperkeratosis;
- Harlequin ichthyosis;
- Congenital ichthyosiform erythroderma.
Another classification of the different types of ichthyosis - defined as "ultrastructural classification" - provides for its subdivision into four types (types I, II, III and IV) according to the structural characteristics of the epidermal cells subjected to biopsy. This classification, however, is used only for the hereditary forms and not for the acquired forms.
Finally, a further classification used to subdivide the forms of hereditary ichthyosis foresees the grouping into:
- Syndromic ichthyosis, ie ichthyosis that occurs both in the skin and in other organs;
- Non syndromic ichthyosis, ie types of ichthyosis that occur only in the skin.
Incidence
Severe ichthyosis of the legs. Image from en.wikipedia.org - See Other Fish Pictures
Excluding vulgar ichthyosis, these diseases are rare forms, which occur mostly in one subject for every 3, 000 people; the ichthyosis linked to the X chromosome and the Harlequin ichthyosis register an incidence index equal, respectively, to 1: 300, 000 and 1: 500, 000 / 1, 000, 000.
Due to the rarity of incidence, Arlecchino ichthyosis is sometimes excluded from the common list of ichthyosis.
Types of ichthyosis
The table below lists the most well-known types of levies and summarizes the main characters that distinguish one form from another.
| Form of ichthyosis | Linked to the X chromosome | lamellar | Vulgar ichthyosis | Epidermolytic hyperkeratosis | Congenital ichthyosiform erythrodermia | Harlequin * or diffuse ichthyosis |
| Areas affected | Trunk, neck. Does not affect hands or feet | It affects the palms of the hands and the feet of the feet, but the entire surface can be affected | Back, palm of the hands, plantar of the feet, extensor zones | Micro warts spread throughout the body surface, particularly the limbs | Palmi (mostly) | The whole body |
| Transmission | Recessive, linked to the X chromosome | Autosomal recessive transmission. Very rare disease | Autosomal dominant transmission | Very rare pathology (1: 500, 000) | Autosomal dominant. Rare disease (1: 300, 000) | Rare autosomal recessive (1 case in a million). It occurs at birth and can result in death |
| Related diseases | Disorders of vision (affects the cornea) | Ectropion or piaghetta (abnormal presence of the intracervical mucosa in the cervix) | Keratosis pilare, atopy | Keratin disorders, hyperkeratosis, diffuse erythema | Erythema, hyperkeratosis | Lips and eyelids spilled outwards. The scales are square (hence "Arlecchino") |
| Features | The scales and lamellas are large, but not very thick with a dark color. It appears already at birth, or in childhood | The lamellas are large, developed and wide. It appears at birth. It is also called collodion baby | The scales are thin. The disorder arises during childhood | The lower atria often have warts and bubbles | The lesions manifest themselves as serous bubbles that tend to burst | More serious form of ichthyosis. Thick skin, which prevents movement |
Finally, we recall that among the various forms of ichthyosis, xerosis is also inserted, the lightest and least severe form of skin pathology. Generally, xerosis affects the lower and upper limbs, showing dryness of the skin associated with mild itching, which worsens during the winter season. The itchy sensation is enhanced by the use of aggressive and irritating detergents, which eradicate the protective lipid layer of the skin.
Diagnosis
Since these are relatively rare diseases, the diagnosis of ichthyosis is not always easy to make.
However, the first step in diagnosing the disease is certainly the physical examination that involves the analysis of scales and lamellae that form on the skin of patients. In detail, the doctor will evaluate the appearance and distribution on the body, also determining the possible presence of blisters.
The doctor will then investigate the patient's family history since ichthyosis is a hereditary pathology.
In order to discriminate which form of ichthyosis affects the patient, the doctor can then resort to tests such as biopsy, which can be associated with molecular genetic analysis in order to definitively confirm the diagnosis.
Finally, some forms of ichthyosis can also be diagnosed in the prenatal phase. For example, ichthyosis linked to the X chromosome can be diagnosed by performing amniocentesis; while lamellar ichthyosis, Harlequin ichthyosis and epidermolytic hyperkeratosis can be diagnosed in the prenatal phase by performing fetoscopy.
Symptoms
To learn more: Symptoms Ichthyosis
The first symptoms of hereditary ichthyosis usually appear shortly after birth, or in any case within the first year of a child's life.
The ichthyosis can manifest itself simply with dry skin, or it can result in more serious forms, presenting thickening of the skin associated with scales and gills that disfigure and disfigure the image of the person and that can create more or less serious problems for the individuals who are affections.
The alteration of the keratinization, in fact, involves the accumulation and overlapping of dead cells one to the other, which scale the skin connoting it of the typical characteristics of dry skin (more marked phenomenon in the rare forms of ichthyosis).
The severity of skin thickening and the formation of scales and lamellae depends on the form of osteosis of which the patient suffers. Depending on their severity, the cutaneous manifestations of ichthyosis can lead to consequences - sometimes even very serious - both physical and psychological.
In other cases, on the other hand, the ichthyosis may itself be the symptom of other basic pathologies that afflict the patient (see the chapter "Associated diseases"). This is the case of acquired ichthyosis.
Predisposing factors
Since skin dryness is one of the typical symptoms of various forms of ichthyosis, the cold and dry climate could enhance and favor the ichthyosic manifestation, but it can never represent its triggering cause, since ichthyosis are genetic pathologies.
Complications
As just stated, the skin symptomatology of the various types of ichthyosis can lead to different physical and psychological consequences. The severity of these consequences is generally greater the more severe is the form of ichthyosis of which the patient suffers.
Physical complications
Depending on the body area in which the symptoms of ichthyosis occur, various complications can arise due to skin thickening, such as:
- Difficulties in movement and difficulty in walking, especially if the ichthyosis occurs in the soles of the feet;
- Hair growth disorders;
- Difficulty closing eyes;
- Difficulty transpiration, as thickening of the skin can hinder this physiological process.
Furthermore, the dryness and thickening of the skin that occurs in individuals suffering from ichthyosis make the skin unelastic and favor its rupture. The cracked and no longer intact skin is so easily exposed to the contraction of possible bacterial, viral or fungal infections.
Psychological complications
The appearance of an individual suffering from ichthyosis can be profoundly altered, leading, in some cases, to serious psychological complications. Generally, children and adolescents are the ones most affected by this type of consequences, since the "different" physical appearance and the resulting physical complications can make meetings and relationships with peers very difficult.
Associated diseases
As mentioned above, ichthyosis can be a symptom of other diseases: the Refsum syndrome and Sjögren-Larsson syndrome are two examples.
The first represents a rare hereditary pathology that involves ataxia (loss of muscle coordination), polyneuritis (inflammation of the nerves) and deafness; while the second syndrome is associated with muscular paralysis with progressive mental retardation.
Leprosy, AIDS and hypothyroidism represent three other pathologies that begin with different forms of acquired ichthyosis; also sarcoidosis shows signs of typical ichthyosis (consistent scales developed in the lower limbs). The biopsy of the skin affected by ichthyosis does not always give good results, on the contrary, in most cases it is useless for the diagnosis.
Treatment
Considering that ichthyosis is included among genetically transmitted diseases, treatment is almost impossible.
However, there are some treatments that can be carried out in order to alleviate the symptoms. In this regard, we can distinguish topical treatment from systemic treatment. However, the latter cannot be used on all patients suffering from ichthyosis.
Topical treatment
The topical treatment of ichthyosis aims to reduce skin thickening and restore lost hydration to the skin.
To achieve the first objective, normally, pharmaceutical preparations (creams or lotions) are used based on keratolytic agents capable of eliminating skin scales.
In this regard, active ingredients such as salicylic acid, urea and alpha-hydroxy acids (such as, for example, glycolic acid) are particularly useful.
In some cases, the use of drugs for topical use (creams, lotions, gels, ointments, etc.) based on retinoids can be effective.
However, the use of these substances is certainly not free from side effects. In fact, alpha-hydroxy acids could be irritating to dry and dehydrated skin of individuals suffering from ichthyosis. In addition, in the presence of cuts and cracks, the aforementioned active ingredients could be absorbed causing potentially serious side effects even at the systemic level.
For this reason, topical treatment of ichthyosis must always take place under the strict supervision of the doctor.
To give the skin lost hydration and elasticity, instead, it can be useful to use moisturizing products and products based on Vaseline and emollients, very useful and highly recommended to soften the skin.
If the ichthyosis is caused by a systemic disorder, it would be good to lubricate the affected areas with substances such as propylene glycol (humectant). This substance is also effective in lightening the symptoms derived from lamellar ichthyosis or ichthyosis linked to the X chromosome. In children, occlusive bandages are not recommended.
Systemic treatment
For most ichthyosic diseases, retinoids represent a very effective cure, which does not completely combat the disease, but can certainly heal the symptoms. Retinoids are administered orally.
However, in general, the systemic use of retinoids is advisable in severe cases of ichthyosis. In other cases, on the other hand, their topical use associated with the local application of preparations that promote the emollient, nourishing and keratolytic action (vaseline, urea, glycerin, glycolic and salicylic acid) may be sufficient.
In any case, it should be remembered that oral retinoids can cause various side effects (such as increased triglyceride blood levels), particularly when used for long periods of time, as is the case with patients suffering from ichthyosis .
Not to forget, then, that retinoids are potential teratogens and, consequently, their use is absolutely prohibited during pregnancy.
In subjects suffering from epidermolytic hyperkeratosis, instead, the ideal treatment is represented by cloxacillin or erythromycin, antibiotics useful in the prevention of pain associated with malodorous pustules that form following the contraction of a bacterial superinfection.
Psychological treatment
In the event that the ichthyosis leads to psychological and social complications - in addition to the pharmacological treatment aimed at alleviating the cutaneous symptoms of the disease - it will be necessary to provide the patient with adequate support and psycho-social support, in order to avoid further and more serious complications.
Useful tips
To improve the efficacy of ichthyosis treatments - whether topical or systemic - and to get relief from the symptoms of the disease, it may be useful to take small steps, such as:
- Reduce the frequency of washing to avoid aggravating skin irritation;
- Do not use toxic substances, with high absorption (eg hexachlorophene, a bactericidal substance / disinfectant) and irritating products;
- Prefer the use of mild detergents, even better if prescribed or recommended by your doctor;
- Avoid direct and excessive exposure to atmospheric agents that can dry out, dehydrate and further irritate the skin (sun, wind, cold, etc.);
- Always follow the doctor's instructions scrupulously and never rely on DIY.
To learn more: Drugs for the treatment of ichthyosis "
