A physician often can diagnose ichthyosis by looking at the skin. A family history is very useful. In some cases, a skin biopsy is done to help to confirm the diagnosis. In some instances, genetic testing may be helpful in making a diagnosis. Diabetes has not been definitively linked to acquired ichthyosis or ichthyosis vulgaris; however, there are case reports associating new onset ichthyosis with diabetes.

Ichthyosis has been found to be more common in Native American, Asian, Mongolian groups. There is no way to prevent ichthyosis.

Ichthyosis is a genetically and phenotypically heterogeneous disease that can be isolated and restricted to the skin manifestations or associated with extracutaneous symptoms. One of which is limb reduction defect known as CHILD syndrome; a rare inborn error of metabolism of cholesterol biosynthesis that is usually restricted to one side of the body. A research done in Egypt proved that it is not a child syndrome and discussed all the case report.

XLI can be suspected based on clinical findings, although symptoms can take varying amounts of time to become evident, from a few hours after birth, up to a year in milder cases. The diagnosis is usually made by a dermatologist, who also typically formulates the treatment plan (see below). STS enzyme deficiency is confirmed using a clinically available biochemical assay. Carrier detection can be performed in mothers of affected sons using this test (see Genetics, below). Molecular testing for DNA deletions or mutations is also offered, and can be particularly useful in the evaluation of individuals with associated medical conditions (see below). Prenatal diagnosis is possible using either biochemical or molecular tests. However, the use of prenatal diagnosis for genetic conditions that are considered to be generally benign raises serious ethical considerations and requires detailed genetic counseling.

The symptoms would appear at birth or shortly after birth. The combination of physical symptoms on the child would suggest they have CHILD syndrome. A skin sample examined under a microscope would suggest the characteristics of the syndrome and an X-Ray of the trunk, arms, and legs would help to detect underdeveloped bones. A CT scan would help detect problems of the internal organs.

Diagnosis can be made at birth by identifying the symptoms of the child. Ultrastructural diagnosis where tissues are analyzed is using electron microscopy is also conducted. A specimen of skin is obtained via a skin biopsy and analyzed to see any tell tale characteristics.Genetic testing can also be done to identify the mutation on the FATP4 gene associated with fatty acid synthesis. Genetic consultation through a genetic counsellor is done to determine whether the individual has this syndrome and reduces the chances of misdiagnoses with other cutaneous diseases.

The diagnosis of harlequin-type ichthyosis relies on both physical examination and certain laboratory tests.

Physical assessment at birth is vital for the initial diagnosis of harlequin ichthyosis. Physical examination reveals characteristic symptoms of the condition especially the abnormalities in the skin surface of newborns. Abnormal findings in physical assessments usually result in employing other diagnostic tests to ascertain the diagnosis.

Genetic testing is the most specific diagnostic test for harlequin ichthyosis. This test reveals a loss of function mutation on the ABCA12 gene. This gene is important in the regulation of protein synthesis for the development of the skin layer. Mutations in the gene may cause impaired transport of lipids in the skin layer and may also lead to shrunken versions of the proteins responsible for skin development. Less severe mutations result in a collodion membrane and congenital ichthyosiform erythroderma-like presentation. ABCA12 is an ATP binding cassette (ABC) transporter, and is a member of a large family of proteins that hydrolyze ATP to transport cargo across membranes. ABCA12 is thought to be a lipid transporter in keratinocytes necessary for lipid transport into lamellar granules during the formation of the lipid barrier.

Biopsy of skin may be done to assess the histologic characteristics of the cells. Histological findings usually reveal hyperkeratotic skin cells, which leads to a thick, white and hard skin layer.

Arts syndrome should be included in the differential diagnosis of infantile hypotonia and weakness aggravated by recurrent infection with a family history of X-linked inheritance. Sequence analysis of PRPS1, the only gene associated with Arts syndrome, has detected mutations in both kindreds reported to date. Arts syndrome patients were also found to have reduced levels of hypoxanthine levels in urine and uric acid levels in the serum. In vitro, PRS-1 activity was reduced in erythrocytes and fibroblasts.

Weissenbacher-Zweymüller syndrome is diagnosed upon a thorough clinical evaluation, detailed patient history, identification of characteristic symptom and a variety of specialized tests which includes x-rays.

There are no life-threatening complications after the perinatal period (around the time of birth) and the skin conditions persist but to a lesser degree of severity. Individuals have a favourable prognosis as symptoms can be managed and past the infancy stage are not life-threatening. The red skin edema improves after a three-week period but the ichthyosis scaling persists. Asthma has been recorded in some cases later on in the individual's life and sign of atopic dermatitis persist, follicular hyperkeratosis and small amounts of scaling at the scalp that goes on into adulthood but otherwise the individual continues a healthy life.

Diagnosis is based on appearance and family history. KID syndrome or keratosis follicularis spinulosa decalvans have some similar symptoms and must be eliminated.

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.

Because XLI is caused by a gene mutation or deletion, there is no "cure." One of the aims of treatment is to reduce scaling by removing the excess, flaky scales, and keep the skin hydrated. This can be achieved using a variety of topical creams.

- Keratolytic agents such as Ammonium lactate (Lac-Hydrin) are used to facilitate the release of retained corneocytes.

- Topical isotretinoin

- The topical receptor-selective retinoid tazarotene

Research is ongoing with regard to the use of gene therapy to treat XLI.

Overheating: The scaling of the skin prevents normal sweating so hot weather and/or vigorous exercise can cause problems.

Eye problems: The eyelids can be pulled down by the tightness of the skin and this can make eyelids (but usually just the lower one) very red and they are prone to drying and irritation.

Constriction bands: Very rarely children with this condition can have tight bands of skin around their fingers or toes (usually at the tips) that can prevent proper blood circulation to the area.

Hair loss: Severe scaling of the skin on the scalp can lead to patchy loss of hair, but this is rarely permanent.

There is currently no treatment for CHILD syndrome so any treatment would target the symptoms currently present. Emoillents like Lac-Hydran (ammonium lactate) and Ureaphil (urea) are used to treat scaly patches on the skin. A pediatric orthopedic surgeon can evaluate any underdevelopment in the bones and treat them if necessary.

There is a compound that is a topical liquid that can calm lesions down on older adults and make them go away on younger children. The mixture was made by Dr. Amy Paller at Children's Hospital. It is mixed as follows: to make 250 ml: Grind up lovastatin tablets 5g (10-20-40-80 mg); mix with cholesterol NF powder (NDC# 51927-1203-00, PCCA) 5g; mix with preserved water while mixing (eventually mixing for 1/2 hour with electronic mortar and pestle) to bring to full volume with preserved water. 8 oz

Sabinas brittle hair syndrome is inherited as an autosomal recessive genetic trait.

In a study by Howell et al. patients were located and studied by means of complete histories and physical examinations, analyses of serum trace metals, ceruloplasmin concentration, urine and serum amino acids, and routine metabolic urine screens. In addition, serum and urine luteinizing hormone (LH) and follicle-stimulating hormone (FSH) values were determined, and were interpreted in conjunction with total plasma estrogen, estradiol, and testosterone levels. Close examination demonstrated the scalp hairs were very brittle, coarse, wiry in texture, and broke off quite easily with mechanical trauma such as combing and brushing. Some hairs could be visualized in their follicles, which were broken off at the skin line. Most patients had accompanying hyperkeratosis (thickening of the skin) of moderate degree on exposed surfaces. Maxillary hypoplasia (midfacial retrusion) was significant in many patients. The brittle, short hair, reduced eyelashes, crowded teeth, and dull appearance created a characteristic facial appearance. Post-pubertal patients had development of secondary sexual characteristics consistent with their age, except for sparse pubic escutcheons. All cases studied demonstrated some degree of mental deficiency; I.Q.'s ranged between 50–60. A deficiency in eye–hand coordination was also noted.

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.

There is no cure as of now. Treatment is directed towards the specific symptoms that are present in each individual. Individuals with hearing loss are able to get treated with hearing aids.

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:

Currently, purine replacement via S-adenosylmethionine (SAM) supplementation in people with Arts syndrome appears to improve their condition. This suggests that SAM supplementation can alleviate symptoms of PRPS1 deficient patients by replacing purine nucleotides and open new avenues of therapeutic intervention. Other non-clinical treatment options include educational programs tailored to their individual needs. Sensorineural hearing loss has been treated with cochlear implantation with good results. Ataxia and visual impairment from optic atrophy are treated in a routine manner. Routine immunizations against common childhood infections and annual influenza immunization can also help prevent any secondary infections from occurring.

Regular neuropsychological, audiologic, and ophthalmologic examinations are also recommended.

Carrier testing for at-risk relatives and prenatal testing for pregnancies at increased risk are possible if the disease-causing mutation in the family is known.

The diagnosis of Muenke syndrome is suspected bases on abnormal skull shape and a diagnosis of coronal craniosynostosis. In 2006, Agochukwu and her colleagues concluded that “A distinct Muenke syndrome phenotype includes: uni or bilateral coronal synostosis, midface hypoplasia, broad toes, and brachydactyly.” Due to phenotypic overlap and/or mild phenotypes, clinical differentiation of this syndrome may be difficult. The suspected diagnosis is confirmed by a blood test to check for gene mutation. To establish the extent of disease in an individual diagnosed with Muenke syndrome, various evaluations are recommended.

Sjögren–Larsson syndrome (SLS) is an autosomal recessive form of ichthyosis apparent at birth.

Sjögren–Larsson syndrome is a rare autosomal, recessive, neurocutaneous disease. This disease can be identified by a triad of medical disorders. The first is ichthyosis, which is a buildup of skin to form a scale-like covering that causes dry skin and other problems. The second identifier is spastic paraplegia which is characterized by leg spasms. The final identifier is intellectual delay.

The gene of SLS is found on chromosome 17. In order for a child to receive SLS both parents must be carriers of the SLS gene. If they are carriers their child has a ¼ chance of getting the disease. In 1957 Sjogren and Larsson proposed that the Swedes with the disease all descended from a common ancestor 600 years ago. Today only 30–40 persons in Sweden have this disease.

Craniometaphyseal dysplasia is diagnosed based on clinical and radiographic findings that include hyperostosis. Some things such as cranial base sclerosis and nasal sinuses obstruction can be seen during the beginning of the child's life. In radiographic findings the most common thing that will be found is the narrowing of foramen magnum and the widening of long bones. Once spotted treatment is soon suggested to prevent further compression of the foramen magnum and disabling conditions.

There is no known cure at the moment but there are several things that can be done to relieve the symptoms. Moisturising products are very helpful to minimize the scaling/cracking, and anti-infective treatments are useful when appropriate because the skin is very susceptible to infection. Extra protein in the diet during childhood is also beneficial, to replace that which is lost through the previously mentioned "leaky" skin.

Steroid and retinoid products have been proven ineffective against Netherton syndrome, and may in fact make things worse for the affected individual.

Intravenous immunoglobulin has become established as the treatment of choice in Netherton's syndrome. This therapy reduces infection; enables improvement and even resolution of the skin and hair abnormalities, and dramatically improves quality of life of the patients; although exactly how it achieves this is not known. Given this; it is possible that the reason Netherton's usually is not very severe at or shortly after birth is due to a protective effect of maternal antibodies; which cross the placenta but wane by four to six months.

Modeling EEC syndrome in vitro has been achieved by reprogramming EEC fibroblasts carrying mutations R304W and R204W into induced pluripotent stem cell (iPSC) lines. EEC-iPSC recapitulated defective epidermal and corneal fates. This model further identified PRIMA-1MET, a small compound that was identified as a compound targeting and reactivating p53 mutants based on a cell-based screening for rescuing the apoptotic activity of p53, as efficient to rescue R304W mutation defect. Of interest, similar effect had been observed on keratinocytes derived from the same patients. PRIMA-1MET could become an effective therapeutic tool for EEC patients.

Further genetic research is necessary to identify and rule out other possible loci contributing to EEC syndrome, though it seems certain that disruption of the p63 gene is involved to some extent. In addition, genetic research with an emphasis on genetic syndrome differentiation should prove to be very useful in distinguishing between syndromes that present with very similar clinical findings. There is much debate in current literature regarding clinical markers for syndromic diagnoses. Genetic findings could have great implications in clinical diagnosis and treatment of not only EEC, but also many other related syndromes.

The only treatment for this disorder is surgery to reduce the compression of cranial nerves and spinal cord. However, bone regrowth is common since the surgical procedure can be technically difficult. Genetic counseling is offered to the families of the people with this disorder.

As with all types of ichthyosis, there is no cure but the symptoms can be relieved.

- Moisturizers

- Prevention of overheating

- Eye drops (to prevent the eyes from becoming dried out)

- Systemic Retinoids (isotretinoin and acitretin are very effective, but careful monitoring for toxicity is required. Only severe cases may require intermittent therapy.)

Psychological therapy or support may be required as well.