There are many types of ichthyosis and an exact diagnosis may be difficult. Types of ichthyosis are classified by their appearance and their genetic cause. Ichthyoses caused by the same gene can vary considerably in severity and symptoms. Some ichthyoses don't appear to fit exactly into any one type. Also different genes can produce ichthyosis with similar symptoms. The most common or well-known types are as follows:
- Ichthyosis vulgaris
- X-linked ichthyosis
- Congenital ichthyosiform erythroderma (nbCIE)
- Epidermolytic hyperkeratosis (bullous ichthyosis, bCIE)
- Harlequin type ichthyosis
- Ichthyosis bullosa of Siemens
- Ichthyosis hystrix
- Ichthyosis lamellaris (lamellar ichthyosis)
- CHILD Syndrome
- Conradi-Hünermann syndrome
- Darier's disease
- Erythrokeratodermia variabilis (Erythrokeratodermia figurata variabilis, Mendes da Costa type erythrokeratodermia)
- IFAP syndrome (Ichthyosis follicularis)
- Keratitis-ichthyosis-deafness syndrome (Senter syndrome)
- Netherton syndrome
- Neutral lipid storage disease (Dorfman-Chanarin syndrome)
- Refsum's disease
- Rud syndrome
- Sjögren-Larsson syndrome
- Tay syndrome (IBIDS syndrome, Trichothiodystrophy)
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 a biopsy, a small piece of skin is removed and examined under a microscope. In some instances, genetic testing may be helpful in making a diagnosis.
Ichthyosis is not more or less common in any ethnic group. As of now, there is no way to prevent ichthyosis.
Treatments for ichthyosis often take the form of topical application of creams and emollient oils, in an attempt to hydrate the skin. Retinoids are also used for some conditions. Exposure to sunlight may improve or worsen the condition.
There can be ocular manifestations of ichthyosis, such as corneal and ocular surface diseases. Vascularizing keratitis, which is more commonly found in congenital keratitis-ichythosis-deafness (KID), may worsen with isotretinoin therapy.
Ichthyosis or ichthyosis-like diseases exist for several types of animals, including cattle, chickens, llamas, mice, and dogs. Ichthyosis of varying severity is well-documented in some popular breeds of domestic dogs. The most common breeds to have ichthyosis are Golden retrievers, American bulldogs, Jack Russell terriers, and Cairn terriers.