Ectodermal Dysplasia Workup

Updated: Feb 11, 2019
  • Author: Kara N Shah, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Laboratory Studies

In general, laboratory studies are not useful in the diagnosis or management of the ectodermal dysplasias.

Patients with ectodermal dysplasia associated with immunodeficiency may have hypogammaglobulinemia with impaired lymphocyte proliferation and cell-mediated immunity. An appropriate evaluation, including determination of quantitative immunoglobulin levels and T-cell subset populations, should be performed.

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Imaging Studies

Perform orthopantography at an early age if hypodontia or dental abnormalities are present.

X-ray films of hands, feet, or both may demonstrate specific skeletal deformities.

Renal ultrasonography, voiding cystourethrography, and intravenous pyelography may be helpful in evaluating children with ectodermal dysplasia in association with cleft lip and/or palate for underlying genitourinary tract anomalies.

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Other Tests

Sweat pore counts, pilocarpine iontophoresis, and skin biopsy may document hypohidrosis and a reduction in the number of eccrine glands.

Sweat pore counts may be performed using yellow starch–iodine powder applied to palmar or dorsal skin. In unaffected persons, sweating turns the yellow starch–iodine powder to deep purple, allowing visualization of sweat pores. Sweat pores are poorly visualized in affected children. Female carriers of X-linked EDA may demonstrate a mosaic pattern of areas of normal numbers of sweat pores alternating with areas of absent pores. Streaky areas of hypohidrosis that follow Blaschko lines are observed upon starch-iodine staining.

For skin biopsy, the hypothenar eminence is the most reliable biopsy site in order to demonstrate an absence or hypoplasia of sweat glands. Fetal skin biopsy may help identify the presence of decreased numbers of eccrine sweat glands for prenatal diagnosis of hypohidrotic ectodermal dysplasia.

Prenatal diagnosis using genetic mutation analysis may be performed for those ectodermal dysplasias in which the genetic mutation is known.

Indirect prenatal diagnosis may be performed by linkage analysis applied to chorionic villus samples at the 10th week of gestation for some ectodermal dysplasias.

Genetic testing for several forms of ectodermal dysplasia, including hidrotic ectodermal dysplasia; X-linked recessive and autosomal dominant hypohidrotic ectodermal dysplasia; EEC syndrome, AEC syndrome, and other related ectodermal dysplasias and WNT10A-associated ectodermal dysplasias is available through GeneDx.

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Histologic Findings

Skin histopathology documents a reduction in the number of sweat glands, hair follicles, and sebaceous glands associated with the different ectodermal dysplasias. In EDA, the epidermis is thin and flattened. Eccrine sweat glands are few or poorly developed or are very rudimentary. Beyond the skin, mucous glands in the upper respiratory tract and bronchi are often reduced in number. Salivary glands may show ectasia of ducts and inflammatory changes.

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