Information on the following diseases can be found in the Related Disorders section of this report:

• Ichthyosis
• Ichthyosis Congenita
• X-Linked Ichthyosis
• Keratitis Ichthyosis Deafness Syndrome

Keratosis follicularis spinulosa decalvans is one form of the ichthyoses, a group of inherited disorders of the skin in which the skin tends to be thick and rough, and to have a scaly appearance. Hardening of the skin around the hair follicles leads to scarring and baldness. Allergic reactions (atopy), reduced tolerance of bright light (photophobia), and inflammation of the eye’s cornea (keratitis) may also occur. Occasionally, the teeth become stained.

The word decalvans comes from the Greek for snake and alludes to the whorls and winding streaks characteristic of the pattern of baldness in this disorder. The name is often accompanied by the phrase "cum ophiasi" which simply means baldness.

Keratosis follicularis spinulosa decalvans is inherited as an X-linked dominant trait.

Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated "p" and a long arm designated "q". Chromosomes are further subdivided into many bands that are numbered. For example, "chromosome Xp22.2-p22.13" refers to a region between bands 22.2 and 22.13 on the short arm of the X chromo-some. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.

X-linked dominant disorders are caused by an abnormal gene on the X chromosome, but in these rare conditions, females with an abnormal gene are affected with the disease. Males with an abnormal gene are more severely affected than females, and many of these males do not survive.

Keratosis Follicularis Spinulosa Decalvans is a rare disorder affecting males more severely than females.

Symptoms of the following disorders may be similar to those of Keratosis Follicularis Spinulosa Decalvans. Comparisons can be useful for a differential diagnosis:

"Ichthyosis" or "Disorders of Cornification" are general terms describing a group of scaly skin disorders. They are characterized by an abnormal accumulation of large amounts of dead skin cells (squames) in the top layer of the skin. The conversion of an abnormally large number of epidermal cells into squamous cells is thought to be caused by a defect in the metabolism of skin cells known as "corneocytes" or of the fat-rich matrix around these cells. The cells can be thought of as bricks, while the matrix would be the mortar holding these cells together. (See "Ichthyosis" in the Rare Disease Database.)

Ichthyosis Congenita (Collodion Baby; Congenital Ichthyosiform Erythroderma; Xeroderma; Desquamation of Newborn) is an inherited skin disorder. It is characterized by generalized, abnormally red, dry and rough skin, with large, coarse scales. Itchiness (pruritus) usually also develops. Skin on the palms of the hands and soles of the feet is abnormally thick. (For more information, choose "Ichthyosis Congenita" as your search term in the Rare Disease Database.)

X-Linked Ichthyosis is an inherited skin disorder affecting males, which is caused by a deficiency of the enzyme steroid sulfatase. This enzyme deficiency leads to biochemical alterations in steroid hormone metabolism. Cholesterol sulfate may accumulate in the blood and skin. (For more information, choose "X-Linked Ichthyosis" as your search term in the Rare Disease Database.)

Keratitis Ichthyosis Deafness (KID) Syndrome is a very rare disorder, thought to be inherited. It is characterized by inflammation of the eye's cornea (keratitis), fixed hardened skin scales (plaques) on the extremities and face, thick hardened skin on the palms of the hands and the soles of the feet, and deafness. (For more information, choose "Keratitis" as your search term in the Rare Disease Database.)

Other forms of Ichthyosis include Sjogren-Larsson Syndrome, Netherton Syndrome, Ichthyosis Hystrix, Lamellar Ichthyosis, Refsum Syndrome, Darier Disease, Conradi-Hunermann Syndrome, Chanarin-Dorfman Syndrome, and Epidermolytic Hyperkeratosis. (Choose the appropriate name as your search term for more information on that disorder in the Rare Disease Database.)

Diagnosis
In most instances the appearance of the skin determines the diagnosis but a family history and physical examination are often required to rule out other possible causes of scaly, dry skin.

Some physicians may examine skin tissue under a light microscope or even under an electron microscope.

Treatment
The dry scaly skin of KFSD is treated by applying skin softening (emollient) ointments, preferably plain petroleum jelly. This can be especially effective after bathing while the skin is still moist. Salicylic acid gel is another particularly effective ointment. The skin should be covered at night with an airtight, waterproof dressing when this ointment is used. Lactate lotion can also be an effective treatment for this disorder.

Drugs derived from Vitamin A (retinoids) such as tretinoin, motretinide, and etretinate are often effective against symptoms of Ichthyosis, but can cause toxic effects on the bones in some cases. A synthetic derivative of Vitamin A, isotretinoin, when taken by pregnant women, can cause severe birth defects to the fetus. These Vitamin A compounds have not yet been approved by the Food and Drug Administration (FDA) for treatment of Ichthyosis, and should be avoided by women of child-bearing age.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

McKusick VA, ed. Online Mendelian Inheritance In Man (OMIM). The Johns Hopkins University. Keratosis Follicularis Spinulosa Decalvans cum Ophiasi; KFSD. Entry Number; 308800: Last Edit Date; 5/20/2003.

TEXTBOOKS
Sybert VP. Ichthyosis. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:120-21..

Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:831-32.

Berkow R., ed. The Merck Manual-Home Edition.2nd ed. Whitehouse Station, NJ: Merck Research Laboratories; 2003:1192.

Champion RH, Burton JL, Ebling FJG. eds. Textbook of Dermatology. 5th ed. Blackwell Scientific Publications. London, UK; 1992:1329-65.

REVIEW ARTICLE
Alfadley A, Al Hawsawi K, Hainau B, et al. Two brothers with keratosis follicularis spinulosa decalvans. J Am Acad Dermatol. 2002;47(5 Suppl):S275-78.

JOURNAL ARTICLES
Porteous ME, Strain L, Logie LJ, et al. Keratosis follicularis spinulosa decalvans: confirmation of linkage to Xp22.13-p22.2. J Med Genet. 1998;35:336-37.

Romine KA, Rothschild JG, Hansen RC. Cicatricial alopecia and keratosis pilaris. Keratosis follicularis spinulosa decalvans. Arch Dermatol. 1997;133:381, 384.

Herd RM, Benton EC. Keratosis follicularis spinulosa decalvans: report of a new pedigree. Br J Dermatol. 1996;134:138-42.

FROM THE INTERNET
Keratosis follicularis spinulosa decalvans. Orphanet. nd.
www.orpha.net/concor/cgi-bin/Pages/Service/Signe/Service_PatSgn_Data.php?PatId=2192

Ichthyosis. British Association of Dermatologists. nd. 5pp.
www.bad.org.uk/patients/skin_disease_info/ichthyosis/

Ngan V. Ichthyosis. New Zealand Dermatological Society. Last updated 8 September 2003. 4pp.
www.dermnetnz.org/dna.dry.skin/ichth.html