PEDBASE.org - The Pediatric Database - Detailed information of HYPOHIDROTIC (ANHIDROTIC) ECTODERMAL DYSPLASIA

HYPOHIDROTIC (ANHIDROTIC) ECTODERMAL DYSPLASIA

DEFINITION:

An x-linked recessive disorder characterized by a triad of defects including hypohidrosis, hypotrichosis, and anomalous dentation.

EPIDEMIOLOGY:

incidence: ?
age of onset:
- infancy -> childhood
risk factors:
- familial - x-linked recessive
  - chrom.#: Xq12.2-13.1
  - gene: ?
  - also an autosomal recessive form

PATHOGENESIS:

1. Background

also called Christ-Siemens-Touraine Syndrome, Anhidrotic Ectodermal Dysplasia, Ectodermal Polydysplasia, Hypohidrosis-Hypodontia-Hypotrichosis
one in a heterogeneous group of disorders (there may be over 120 different types) characterized by a number of defects involving the teeth, skin, and appendageal structures (hair, nails, and eccrine and sebaceous glands):
1. Hypohidrotic (Anhidrotic) Ectodermal Dysplasia

2. Hidrotic Ectodermal Dysplasia (Clouston Type)

3. EEC Syndrome

4. Rapp-Hodgkin Ectodermal Dysplasia

5. Robinson-Type Ectodermal Dysplasia
the ectodermal dysplasias are due to disturbances in the tissue derived from ectoderm -> absent or hypoplastic glandular systems:
1. Eccrine Glands - sweating deficit

2. Lacrimal Glands - lacrimation deficit

3. Mucous Glands - respiratory manifestations and atopic disease

4. Sebaceous Glands - skin manifestations

full expression in this type is only in males; heterozygote females may have some clinical features

CLINICAL FEATURES:

1. Eccrine Manifestations

1. Hypohidrosis

reduction or absence of sweating
high fever in a warm environment
may present as fever of unknown origin

2. Integument Manifestations

1. Hypotrichosis

sparse, unruly, lightly-pigmented hair
variable alopecia
eyebrows & lashes sparse/absent (lashes may be double-set)

2. Others

dry, hypopigmented skin
prominent venous pattern due to translucent quality of the epidermis
atopic dermatitis

3. Dental Manifestations

1. Anomalous Dentation

hypodontia to anodontia
widely-spaced peg-shaped or conical teeth
numerous caries and discoloured teeth

4. Facial Manifestations

frontal bossing
malar hypoplasia
flattened nasal bridge
prominent low-set ears
prominent chin
thick, everted lips
wrinkled, hyperpigmented periorbital skin

5. Ocular Manifestations

cataracts
corneal dysplasia
defective/diminished lacrimation
stenotic lacrimal puncta

6. Respiratory Manifestations

asthma
dysphonia
hoarseness
recurrent pulmonary infections
rhinitis - atrophic -> purulent

7. Other Manifestations

atopic disease (allergic rhinnitis, asthma, atopic dermatitis)
conductive hearing loss
gonadal abnormalities
hypoplastic or absent mammary glands
mental retardation in selected patients

INVESTIGATIONS:

1. Pathology

biopsy of palmar skin -> absence or hypoplasia of eccrine glands

2. Pilocarpine Iontophoresis

reduction or absence of sweating
topical application of o-phthalaldehyde to palmar skin

MANAGEMENT:

1. Supportive

Eccrine - air conditioning, avoid high temperatures
Integument - topical corticosteroids & antibiotics, wig
Dental - early evaluation for prostheses, close care
Ocular - artificial tears
Respiratory - intermittent saline irrigation, topical petroleum application, bronchodilators, antibiotics, etc

Pediatric Database - HYPOHIDROTIC (ANHIDROTIC) ECTODERMAL DYSPLASIA

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