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.

CIE has symptoms very similar to Lamellar ichthyosis (LI) but milder and is considered by many scientists to be a variant of that disease, so both diseases are grouped under the title autosomal recessive congenital ichthyosis (ARCI).

The baby is often born in a collodion membrane, a shiny, wax outer layer on the skin and usually with ectropion, having the lower eyelid turned outwards. When the membrane is shed the skin is red with a generalized white scale. Palms, soles and areas on the joints are often affected with hyperkeratosis, a thickening of the layer of dead skin cells on the surface of the skin. In classical CIE (unlike LI) there is little eclabion (eversion of the lips), ectropion and alopecia (hair loss).

Many people with ACRI don't fit neatly into the definition of LI or CIE but have characteristics of both diseases. The definitions of CIE and LI describe the extremes of the range of ACRI.

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.

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.

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).

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.

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.

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:

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.

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.

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.

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).

The symptoms associated with the disorder are often confused for other dermatological disorders. The symptoms below are ones specifically associated with IPS.

Red endemic skin as well as spongy and desquamating (peeling) skin are consistent with this syndrome.

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.

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.

HIES often appears early in life with recurrent staphylococcal and candidal infections, pneumonias, and eczematoid skin.

- Autosomal dominant Hyper-IgE Syndrome caused by STAT3 defects, called Job Syndrome, have characteristic facial, dental, and skeletal abnormalities. Patients with STAT3 HIES may have either delay of or failure in shedding of primary teeth. The characteristic facial features are usually set by age 16. These include facial asymmetry, a prominent forehead, deep-set eyes, a broad nasal bridge, a wide, fleshy nasal tip, and mild prognathism. Additionally, facial skin is rough with prominent pores. Finally, some patients with STAT3 HIES have scoliosis, as well as bones that fracture easily.

- Autosomal recessive

Congenital Ichthyosiform Erythroderma (CIE), also known as Nonbullous congenital ichthyosiform erythroderma is a rare type the ichthyosis family of skin diseases which occurs in 1 in 200,000 to 300,000 births.

The major symptoms of XLI include scaling of the skin, particularly on the neck, trunk, and lower extremities. The extensor surfaces are typically the most severely affected areas. The >4 mm diameter scales adhere to the underlying skin and can be dark brown or gray in color. Symptoms may subside during the summer.

In 1937, Touraine and Solente first noted the association between hair-shaft defects (bamboo node) and ichthyosiform erythroderma. Còme first coined the term ichthyosis linearis circumflexa in 1949, although Rille had previously recorded the distinctive features of ichthyosis linearis circumflexa by 1922. In 1958, Netherton described a young girl with generalized scaly dermatitis and fragile nodular hair-shaft deformities, which he termed trichorrhexis nodosa. Later, this was more appropriately renamed as trichorrhexis invaginata (bamboo hair) for a ball-and-socket–type hair-shaft deformity at the suggestion of Wilkinson et al.

In 1974, Mevorah et al. established the clinical relationship between ichthyosis linearis circumflexa and Netherton syndrome, and an atopic diathesis was found to occur in approximately 75% of patients with Netherton syndrome.

This is rare and is usually due to mutations in the R-spondin 4 (RSPO4) gene which is located on the short arm of chromosome 20 (20p13). Clinically it is manifest by the absence (anonychia) or hypoplasia (hyponuchia) of finger- and/or toenails.

Hystrix-like ichthyosis–deafness syndrome (also known as "HID syndrome") is a cutaneous condition characterized by a keratoderma.

Netherton syndrome is characterized by chronic skin inflammation, universal pruritus (itch), severe dehydration, and stunted growth. Patients with this disorder tend to have a hair shaft defect (trichorrhexis invaginata), also known as "bamboo hair". The disrupted skin barrier function in affected individuals also presents a high susceptibility to infection and allergy, leading to the development of scaly, reddish skin similar to atopic dermatitis. In severe cases, these atopic manifestations persist throughout the individual's life, and consequently post-natal mortality rates are high. In less severe cases, this develops into the milder ichthyosis linearis circumflexa.

Netherton syndrome has recently been characterised as a primary immunodeficiency, which straddles the innate and acquired immune system, much as does Wiskott-Aldrich syndrome. A group of Netherton patients have been demonstrated to have altered immunoglobulin levels (typically high IgE and low to normal IgG) and immature natural killer cells. These Natural Killer cells have a reduced lytic function; which can be improved with regular infusions of immunoglobulin (see 'Treatment'); although the mechanism for this is not clear.

Patients are more prone than healthy people to infections of all types, especially recurrent skin infections with staphylococcus. They may have more severe infections; but are not as vulnerable to opportunistic pathogens as patients with true Natural Killer cell deficiency-type SCID.

Elevated IgE is the hallmark of HIES. An IgE level greater than 2,000 IU/mL is often considered diagnostic. However, patients younger than 6 months of age may have very low to non-detectable IgE levels. Eosinophilia is also a common finding with greater than 90% of patients having eosinophil elevations greater than two standard deviations above the normal mean. Genetic testing is available for "STAT3" (Job's Syndrome), "DOCK8 (DOCK8 Immunodeficiency or DIDS)", "PGM3" (PGM3 deficiency), "SPINK5" (Netherton Syndrome - NTS), and "TYK2" genetic defects.

The development of ichthyosis in adulthood can be a manifestation of systemic disease, and it has been described in association with malignancies, drugs, endocrine and metabolic disease, HIV, infection, and autoimmune conditions.

It usually is associated with people who have Hodgkin's disease but it is also occurs in people with mycosis fungoides, other malignant sarcomas, Kaposi's sarcoma and visceral carcinomas. It can occur in people suffering from leprosy, AIDS, tuberculosis, and typhoid fever.