The symptoms of the inherited form of ichthyosis vulgaris are not usually present at birth but generally develop between 3 months and 5 years of age. The symptoms will often improve with age, although they may grow more severe again in old age.

The condition is not life-threatening; the impact on the patient, if it is a mild case, is generally restricted to mild itching and the social impact of having skin with an unusual appearance. People afflicted with mild cases have symptoms that include scaly patches on the shins, fine white scales on the forearms and upper arms, and rough palms. People with the mildest cases have no symptoms other than faint, tell-tale "mosaic lines" between the Achilles tendons and the calf muscles.

Severe cases, although rare, do exist. Severe cases entail the buildup of scales everywhere, with areas of the body that have a concentration of sweat glands being least affected. Areas where the skin rubs against each other, such as the armpits, the groin, and the "folded" areas of the elbow and knees, are less affected. When the buildup of scales is bad, the person with a severe case suffers from "prickly itch" when he or she needs to sweat but cannot because of the scales. Various topical treatments are available to "exfoliate" the scales. These include lotions that contain alpha-hydroxy acids.

Many people with severe ichthyosis have problems sweating due to the buildup of scales on the skin. This may lead to problems such as "prickly itch" or problems associated with overheating. The majority of people with vulgaris can sweat at least a little. Paradoxically this means most would be more comfortable living in a hot and humid climate. Sweating helps to shed scales which improves the appearance of the skin and prevents "prickly itch".

The dry skin will crack on digits or extremities and create bloody cuts. Skin is painful when inflamed and/or tight.

For children and adolescents: psychological precautions may include inconsistent self-image, mood fluctuates due to cyclical outbreaks, prone to addiction, may socially withdraw and/or separate when skin is noticeably infected, pre-occupation with appearance.

Strong air-conditioning and excessive consumption of alcohol can also increase the buildup of scales.

Over 50% of people with ichthyosis vulgaris suffer from some type of atopic disease such as allergies, eczema, or asthma. Another common condition associated with ichthyosis vulgaris is keratosis pilaris (small bumps mainly appearing on the back of the upper arms).

IBS has symptoms very similar to epidermolytic hyperkeratosis (EHK) but is generally milder than EHK. IBS affects only the upper layers of the epidermis whilst EHK affects the suprabasal layer which is deeper in the

skin.

At birth the baby's skin has a red appearance like a sun burn (erythema). Blistering is usually present at birth and may be extensive or localized depending on the severity of the disease.

Over the first few weeks the redness disappears and is replaced by dry, flaking skin on the arms, legs and around the belly button. Other areas of skin appear normal. The skin is fragile and is prone to blistering (caused by mild trauma or sweating). After a few months hyperkeratosis develops with a dark grey or brown, ridged appearance on the ankles, knees and elbows. Palms and soles are generally unaffected. A slightly unpleasant, sweet odour may be present.

A distinctive characteristic of IBS which is not present in other forms of ichthyosis is called the "Mauserung phenomenon" (Mauserung is German for "moulting" and was first described by H.W.Siemens). These are small patches of bare, apparently normal skin in the middle of areas of hyperkeratosis.

As the sufferer ages the flaking and blistering should improve. The hyperkeratosis may grow more severe but more localized and is generally only present on flexural folds of the major joints.

Keratosis pilaris results in small bumps on the skin that feel like rough sandpaper. They are skin-colored bumps the size of a grain of sand, many of which are surrounded by a slight pink color in light skinned people and dark spots in dark skinned people. Most people with keratosis pilaris do not have symptoms but the bumps in the skin can occasionally be itchy.

Though people with keratosis pilaris experience the condition year-round, the problem can become exacerbated and the bumps are likely to look and feel more pronounced in color and texture during the colder months when moisture levels in the air are lower. The symptoms may also worsen during pregnancy or after childbirth.

Keratosis pilaris (KP) (also follicular keratosis, lichen pilaris, or colloquially "chicken skin") is a common, autosomal dominant, genetic condition of the skin's hair follicles characterized by the appearance of rough, slightly red bumps on light skin and brown bumps on darker skin. It most often appears on the back, outer sides of the upper arm (though the forearm can also be affected), face, thighs, and buttocks; KP can also occur on the hands, and tops of legs, sides, or any body part except glabrous skin (like the palms or soles of feet). Often the lesions will appear on the face, which may be mistaken for acne.

Epidermolytic hyperkeratosis is a skin disorder that is present at birth. Affected babies may have very red skin (erythroderma) and severe blisters. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis).

As affected individuals get older, blistering is less frequent, erythroderma becomes less evident, and the skin becomes thick (hyperkeratotic), especially over joints, on areas of skin that come into contact with each other, or on the scalp or neck. This thickened skin is usually darker than normal. Bacteria can grow in the thick skin, often causing a distinct odor.

Epidermolytic hyperkeratosis can be categorized into two types. People with PS-type epidermolytic hyperkeratosis have thick skin on the palms of their hands and soles of their feet (palmoplantar or palm/sole hyperkeratosis) in addition to other areas of the body. People with the other type, NPS-type, do not have extensive palmoplantar hyperkeratosis but do have hyperkeratosis on other areas of the body.

Epidermolytic hyperkeratosis is part of a group of conditions called ichthyoses, which refers to the scaly skin seen in individuals with related disorders. However, in epidermolytic hyperkeratosis, the skin is thick but not scaly as in some of the other conditions in the group.

"http://ghr.nlm.nih.gov/condition/epidermolytic-hyperkeratosis"

Ichthyosis bullosa of Siemens is a type of familial, autosomal dominant ichthyosis, a rare skin disorder. It is also known as bullous congenital ichthyosiform erythroderma of Siemens or ichthyosis exfoliativa. It is a genetic disorder with no known cure which is estimated to affect about 1 in 500,000 people.

Many other conditions can lead to localized scaling or hyperpigmentation.

This condition should firmly be distinguished from dermatitis artefacta, which is the "factitious" creation of a skin lesion, whereas dermatosis neglecta results from unconscious avoidance of cleaning due to pain or immobility.

Other skin conditions which should not be mistaken for dermatosis neglecta include: terra firma-forme dermatosis (in which there is no history of inadequate cleaning); confluent and reticulated papillomatosis of Gougerot and Carteaud; several forms of ichthyosis; acanthosis nigricans; and Vagabond's disease.

Dermatosis neglecta is a skin condition in which accumulation of sebum, keratin, sweat, dirt and debris leads to a localized patch of skin discoloration or a wart-like plaque. It is caused by inadequate hygiene of a certain body part, usually due to some form of disability or a condition that is associated with pain or increased sensitivity to touch (hyperesthesia) or immobility.

Dermatosis neglecta typically develops several months after a disability or other affliction leads to improper cleaning. Patients may deny that negligence is the cause of the lesion, even though it completely resolves on vigorous rubbing with alcohol swabs or water and soap (which provides both diagnosis and treatment). Recognizing the diagnosis avoids unnecessary skin biopsies.

Examples of case reports from the literature include a man who avoided washing the skin area surrounding an artificial pacemaker out of fear it might be damaged; a woman who didn't clean the right side of her chest due to hyperesthesia following an amputation for breast cancer (mastectomy); a girl who was afraid to wash the area around an abdominal scar; and a man with multiple fractures, shoulder dislocation and radial nerve palsy which significantly reduced his mobility.

Keratosis pilaris atropicans includes many forms of keratosis pilaris with cicatricial alopecia. Variants include keratosis pilaris atrophicans faciei, atrophoderma vermiculatum, keratosis follicularis spinulosa decalvans, and ichthyosis follicularis.

There are many types of ichthyoses and an exact diagnosis may be difficult. Types of ichthyoses are classified by their appearance and their genetic cause. Ichthyosis caused by the same gene can vary considerably in severity and symptoms. Some ichthyoses do not appear to fit exactly into any one type. Different genes can produce ichthyoses with similar symptoms. Of note, X-linked ichthyosis is associated with Kallmann syndrome (close to "KAL1" gene). The most common or well-known types are as follows:

Affected babies are born in a collodion membrane, a shiny, waxy-appearing outer layer to the skin. This is shed 10–14 days after birth, revealing the main symptom of the disease, extensive scaling of the skin caused by hyperkeratosis.

With increasing age, the scaling tends to be concentrated around joints in areas such as the groin, the armpits, the inside of the elbow and the neck. The scales often tile the skin and may resemble fish scales.

Epidermolytic ichthyosis (EI), (also known as "epidermolytic hyperkeratosis (EHK)", "bullous congenital ichthyosiform erythroderma (BCIE), bullous ichthyosiform erythroderma, or bullous congenital ichthyosiform erythroderma Brocq) is a rare and severe form of ichthyosis this skin disease affects around 1 in 300,000 people.

It involves the clumping of keratin filaments.

In medicine, the term collodion baby applies to newborns who appear to have an extra layer of skin (known as a "collodion membrane") that has a collodion-like quality. It is a descriptive term, not a specific diagnosis or disorder (as such, it is a syndrome).

Ichthyosis is a family of rare genetic skin disorders characterized by dry, thickened, scaly skin.

There are more than 20 types of ichthyosis which range in severity of symptoms, outward appearance, underlying genetic cause, and mode of inheritance (e.g., whether the abnormal gene inherited is dominant, recessive, autosomal, or X-linked). Ichthyosis comes from the , since dry, scaly skin is the defining feature of all forms of ichthyosis.

The severity of symptoms can vary enormously, from the mildest, most common, type such as ichthyosis vulgaris which may be mistaken for normal dry skin up to life-threatening conditions such as harlequin type ichthyosis. Ichthyosis vulgaris accounts for more than 95% of cases.

Trachyonychia, sometimes called sandpapered nails, is a condition characterized by rough accentuated linear ridges (longitudinal striations) on the nails of the fingers and toes. When the condition occurs on all the twenty nails of the fingers and toes, it is known as twenty-nail dystrophy, most evident in childhood, favoring males.

Trachyonychia causes the nails to become opalescent, thin, dull, fragile, and finely longitudinally ridged, and, as a result, distally notched. It can be a manifestation of lichen planus, psoriasis, alopecia areata, immunoglobulin A deficiency, atopic dermatitis, and ichthyosis vulgaris.

"The longitudinal striations can occur as a normal part of the aging process", and not until the nails start to thin and get a sandpaper look is the condition called trachonychia. The nails are opalescent and frequently are brittle and split at the free margin. There has been evidence of the condition as a cutaneous manifestation of lichen planus. It has also been associated with other diseases such as eczema, psoriasis, alopecia areata, and atopic dermatitis. Trachonychia is often seen in vitiligo patients – suggesting that they are more susceptible to this condition.

Newborns with harlequin-type ichthyosis present with thick, fissured armor-plate hyperkeratosis. Sufferers feature severe cranial and facial deformities. The ears may be very poorly developed or absent entirely, as may the nose. The eyelids may be everted (ectropion), which leaves the eyes and the area around them very susceptible to infection. Babies with this condition often bleed during birth. The lips are pulled back by the dry skin (eclabium). Joints are sometimes lacking in movement, and may be below the normal size. Hypoplasia is sometimes found in the fingers. Polydactyly has also been found on occasion. In addition, the fish mouth appearance, mouth breathing, and xerostomia place affected individuals at extremely high risk for developing rampant dental decay.

Patients with this condition are extremely sensitive to changes in temperature due to their hard cracked skin, which prevents normal heat loss. Respiration is also restricted by the skin, which impedes the chest wall from expanding and drawing in enough air. This can lead to hypoventilation and respiratory failure. Patients are often dehydrated, as their plated skin is not well suited to retaining water.

Ichthyosis en confetti, also known as ichthyosis with confetti, congenital reticular ichthyosiform erythroderma (CRIE) and ichthyosis variegata, is a very rare form of congenital ichthyosis in which healthy patches of normal skin co-exist within the abnormal skin areas. The condition is caused by a frameshift mutation in the keratin 10 gene (KRT10); mutant keratin 10 accumulates in the nucleolus, a sub-nuclear structure, rather than within cellular intermedite filaments like the wild-type protein. Children with the condition exhibit red, flaky skin; however, for reasons not yet totally clear, wild type clonal patches of skin start to appear, in place of the red, flaky skin. Due to the clonal nature of the growth of the normal skin cells, it appears the patient is covered with confetti, hence the name of the condition. It has been hypothesized that this is the result of a combination of mitotic recombination and natural selection within the skin.

Ichthyosis linearis circumflexa is a distinctive skin condition of generalized hyperkeratosis and polycyclic and serpiginous erythematous plaques with a characteristic, migratory, double-edged scale at the margins, and is the typical cutaneous manifestation of Netherton's syndrome.

The symptoms of ichthyosis hystrix Curth-Macklin are similar to epidermolytic hyperkeratosis (NPS-2 type) but there is no blistering and the hyperkeratosis is verrucous or spine-like. The hyperkeratosis is brown-grey in colour and is most obvious on the arms and legs. It is an autosomal dominant condition and can be caused by errors to the KRT1 gene. It is named after Helen Ollendorff Curth (1899-1982), a German-Jewish dermatologist, and Madge Thurlow Macklin (1893–1962), an American medical geneticist, and is one of the first syndromes named after two women.

Skin disorders are among the most common health problems in dogs, and have many causes. The condition of a dog's skin and coat are also an important indicator of its general health. Skin disorders of dogs vary from acute, self-limiting problems to chronic or long-lasting problems requiring life-time treatment. Skin disorders may be primary or secondary (due to scratching, itch) in nature, making diagnosis complicated.

There are two expressions of this condition, one for long or double coated breeds and one for short coated breeds, both with differing presentations.

- For long- or double-coated breeds such as Poodles, Akitas and Samoyeds, the condition often presents itself with silvery dandruff which adheres to the coat, hair loss (not to be confused with moulting or "blowing coat"), a dull and brittle coat, and later on skin lesions along the back and ears as well as thickened skin and a musty or rancid odour.

- For short-coated breeds such as Vizslas, the condition causes facial swellings, nodular skin lesions, fine dandruff which does not adhere to the coat, and a general "moth-eaten" appearance to the coat.

Ichthyosis hystrix is a group of rare skin disorders in the ichthyosis family of skin disorders characterized by massive hyperkeratosis with an appearance like spiny scales. This term is also used to refer to a type of epidermal nevi with extensive bilateral distribution.

LS can occur without symptoms. White patches on the LS body area, itching, pain, pain during sex (in genital LS), easier bruising, cracking, tearing and peeling, and hyperkeratosis are common symptoms in both men and women. In women, the condition most commonly occurs on the vulva and around the anus with ivory-white elevations that may be flat and glistening.

In males, the disease may take the form of whitish patches on the foreskin and its narrowing (preputial stenosis), forming an "indurated ring", which can make retraction more difficult or impossible. In addition there can be lesions, white patches or reddening on the glans. In contrast to women, anal involvement is less frequent. Meatal stenosis, making it more difficult or even impossible to urinate, may also occur.

On the non-genital skin, the disease may manifest as porcelain-white spots with small visible plugs inside the orifices of hair follicles or sweat glands on the surface. Thinning of the skin may also occur.

Trichorrhexis invaginata (also known as "Bamboo hair" ) is a distinctive hair shaft abnormality that may occur sporadically, either in normal hair or with other hair shaft abnormalities, or regularly as a marker for Netherton's syndrome. The primary defect appears to be abnormal keratinization of the hair shaft in the keratogenous zone, allowing for intussusception of the fully keratinized and hard distal shaft into the incompletely keratinized and soft proximal portion of the shaft.