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

• Ichthyosis
• Ichthyosis Congenita
• X-Linked Ichthyosis
• Psoriasis

Erythrokeratodermia Progressiva Symmetrica is a rare form of ichthyosis, a group of skin disorders characterized primarily by scaly skin. Usually, this disorder stabilizes after 1 to 2 years, and partially regresses during puberty. This disorder is characterized by red hardened plaques with clear limits. Skin plaques are distributed symmetrically on the head, buttocks, legs and arms. The palms of the hands and the soles of the feet may be involved. The lesions may be itchy (pruritic).

Erythrokeratodermia Progressiva Symmetrica is a hereditary disorder transmitted through either autosomal recessive or dominant genes.

Human traits, including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother.

In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is 25 percent. Fifty percent of their children risk being carriers of the disease, but generally will not show symptoms of the disorder. Twenty-five percent of their children may receive both normal genes, one from each parent, and will be genetically normal (for that particular trait). The risk is the same for each pregnancy.

In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child.

Erythrokeratodermia Progressiva Symmetrica affects males and females in equal numbers. It is a rare skin condition.

Symptoms of the following disorders may be similar to those of Erythrokeratodermia Progressiva Symmetrica. 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. (For more information, choose "Ichthyosis" as your search term 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, caused by a deficiency of the enzyme steroid sulfatase. This enzyme deficiency leads to biochemical alterations in steroid hormone metabolism and 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.)

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.)

Psoriasis is a common chronic and recurrent skin disorder characterized by dry, well-circumscribed silvery gray scaling spots (papules) or plaques which usually appear on the scalp, elbows, or knees. (For more information, choose "Psoriasis" as your search term in the Rare Disease Database.)

Erythrokeratodermia Progressiva Symmetrica 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.

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 web site.

For information about clinical trials being conducted at the 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

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

GENETICALLY TRANSMITTED, GENERALIZED DISORDERS OF CORNIFICATION. THE ICHTHYOSES: M.L. Williams, et al.; Dermatol Clin (January 1987: issue 5(1)). Pp. 155-178.

THERAPEUTIC ACTIVITY OF LACTATE 12% LOTION IN THE TREATMENT OF ICHTHYOSIS. ACTIVE VERSUS VEHICLE AND ACTIVE VERSUS A PETROLEUM CREAM: M. Buxman, et al.; Journal Am Acad Dermatol (December 1986: issue 15(6)). Pp. 1253-1258.

THE METABOLIC BASIS OF INHERITED DISEASE, 5th ed.: John B. Stanbury, et al., eds.; McGraw Hill, 1983. Pp. 1027-1039.

PROGRESSIVE SYMMETRIC ERYTHROKERATODERMIA. HISTOLOGICAL AND ULTRASTRUCTURAL STUDY OF PATIENT BEFORE AND AFTER TREATMENT WITH ETRETINATE: V. Nazzaro, et al.; Arch Dermatol (April 1986: issue 122(4)). Pp. 434-440.