History
Individuals affected by ectodermal dysplasia have abnormalities in different ectodermal structures. Some ectodermal dysplasia types are mild, while others are devastating. Obvious manifestations of the disorders are not clinically apparent in most newborns. Dental, hair, and nail anomalies usually become evident during infancy or childhood. A family history of similar clinical features is helpful.
Other signs and symptoms that may be variably seen include the following:
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Hyperthermia with fever and seizures
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Xerophthalmia (decreased tears) and conjunctivitis [47]
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Deficient hearing or vision
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Xerostomia (decreased saliva) [48] and frequent dental caries
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Developmental delay or mental retardation
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Dysphagia
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Growth failure [46]
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Signs of airway constriction and inflammation [49]
Physical Examination
Clinical appearance depends on the specific anomalies associated with each disorder. General features may include the following:
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Dry, hypopigmented skin is a feature. A chronic eczematous dermatitis may be present.
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Sweating may be absent or reduced.
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Sparse, fair, brittle hair with alopecia is a feature, as are absent or diminished body hair and sparse or absent eyebrows and eyelashes.
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Nail dystrophy is a feature.
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Dental features may include hypodontia or anodontia; malformed, rudimentary, or pegged teeth; and/or enamel defects and frequent dental caries. [53]
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Diminished lacrimation and salivation are reported.
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Dysmorphic facies is a feature.
Following are several of the well-defined ectodermal dysplasias.
Hypohidrotic ectodermal dysplasia
Hypohidrotic ectodermal dysplasia is characterized by reduced or absent sweating associated with other ectodermal defects. [54]
The typical facies, which is often not recognized until infancy, is characterized by frontal bossing; sunken cheeks; saddle nose; thick, everted lips; wrinkled, hyperpigmented periorbital skin; and large, low-set ears. See the image below.
Wrinkled, hyperpigmented skin around the eyes and everted lips are typical characteristics of anhidrotic/hypohidrotic ectodermal dysplasia syndrome.
Dental manifestations include conical or pegged teeth, hypodontia or complete anodontia, and delayed eruption of permanent teeth.
Most patients have fine, sparse, lusterless, fair hair; therefore, little pigmentation in the hair shaft is observed microscopically and the medulla is often discontinuous. When medullation is present, a "bar code" appearance is often seen.
Onychodystrophy may occur but is not common. Extensive scaling of the skin and unexplained pyrexia secondary to anhidrosis may occur in the neonatal period. The development of a chronic eczematous dermatitis is common. Other common signs are short stature, eye abnormalities, decreased tearing, and photophobia.
X-linked hypohidrotic ectodermal dysplasia (EDA or Christ-Siemens-Touraine syndrome) is the most common ectodermal dysplasia. Female carriers may display a blaschkoid distribution of hypohidrosis as a result of lyonization and somatic mosaicism for the abnormal X chromosome. Autosomal recessive and autosomal dominant forms of hypohidrotic ectodermal dysplasia have been reported but are rare. Intelligence is normal.
Hidrotic ectodermal dysplasia (Clouston syndrome)
Hidrotic ectodermal dysplasia (Clouston syndrome) is inherited in an autosomal dominant manner; the homozygous state may be lethal. It is more common in persons of French-Canadian ancestry. [55, 56, 57]
Scalp hair is very sparse, fine, and brittle and alopecia is common. Eyebrows are thinned or absent. Nail dystrophy is common. Persistent paronychial infections are frequent. Polydactyly, syndactyly, and bulbous fingertips may be present. Patients have normal facies, no specific dental defects, and normal sweating. Other reported findings include reticulate hyperpigmentation of the knees, elbows, and fingers; palmoplantar keratoderma; and eccrine poromatosis.
Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC or Hay-Wells) syndrome
AEC (Hay-Wells) syndrome is inherited as an autosomal dominant trait of variable expressivity. [58] Scaling and erythema may be present at birth. The characteristic facies is due to ankyloblepharon (congenital adhesion of the upper and lower eyelid margins by fibrous bands); a broad nasal bridge; and a sunken, hypoplastic maxilla. Cleft palate is common; cleft lip is rare.
A recalcitrant, crusted, inflammatory scalp dermatitis may cause scarring alopecia. [59] Chronic blepharitis and conjunctivitis may develop. Nails are absent or dystrophic; pegged teeth are common. Mild hypohidrosis is common. Hair may be sparse and coarse.
Ectrodactyly-ectodermal defects-cleft lip/palate (EEC) syndrome
EEC syndrome is inherited as an autosomal dominant trait of low penetrance and variable expressivity. [60] Many sporadic cases have been reported. Ectrodactyly with tetramelic 3-4 syndactyly results in the characteristic lobster-claw deformity of the hands and feet. Hypoplastic metacarpal or metatarsal bones may be present. Cleft lip and palate create a characteristic nasal contour.
Other ectodermal anomalies include mild hypohidrosis; coarse, dry hair with hypotrichosis; xerostomia; dystrophic nails; dental enamel hypoplasia; and microdontia.
Associated defects include blepharophimosis, lacrimal duct anomalies, strabismus, deafness, choanal atresia, and abnormalities of the genitourinary tract. A rare variant, ectrodactyly-ectodermal defects-clefting with urinary tract abnormalities and thymic abnormalities (EEC/EECUT), has also been associated with T-cell lymphopenia. [61]
Rapp-Hodgkin ectodermal dysplasia
Rapp-Hodgkin ectodermal dysplasia is an autosomal dominant syndrome. [62] High forehead, narrow nose, cleft lip or palate, and maxillary hyperplasia produce a distinctive facies. Hypohidrosis is severe enough to result in heat intolerance. Dental defects include conical teeth and hypodontia. Hair is sparse, has a steel-wool texture, and may show pili torti or pili canaliculi, as shown in the images below. Many patients present with recalcitrant, inflammatory scalp dermatitis followed by scarring alopecia. Nails are narrow and dystrophic, also shown below. Occasional abnormalities include deafness, eye defects, and hypospadias.
Abnormal hair shaft showing pili torti and a longitudinal groove (pili canaliculi) from a patient with Rapp-Hodgkin syndrome.
Hands of father and son with Rapp-Hodgkin syndrome. Nails have the same characteristics; they are brittle, thin, and dystrophic.
Complications
Patients with severe dental abnormalities or cleft lip and/or palate may develop feeding difficulties, which may result in malnutrition and failure to thrive.
Patients affected by anodontia may show shrinkage of the bone supporting the denture after long-term denture use.
Patients with anhidrosis/hypohidrosis are prone to hyperpyrexia and heat exhaustion.
Patients with chronic scalp dermatitis and erosions often develop recurrent bacterial and fungal skin infections.
Patients with abnormal mucous gland function may develop secondary infections, especially in the upper respiratory tract.
Patients with immunodeficiency are at risk for recurrent viral, bacterial, and fungal infections.
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A newborn boy with anhidrotic/hypohidrotic ectodermal dysplasia syndrome showing generalized fine scaling and a history of intermittent fever.
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Wrinkled, hyperpigmented skin around the eyes and everted lips are typical characteristics of anhidrotic/hypohidrotic ectodermal dysplasia syndrome.
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Typical cleft lip/palate and maxillary hyperplasia in a patient with Rapp-Hodgkin syndrome.
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Abnormal hair shaft showing pili torti and a longitudinal groove (pili canaliculi) from a patient with Rapp-Hodgkin syndrome.
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Hands of father and son with Rapp-Hodgkin syndrome. Nails have the same characteristics; they are brittle, thin, and dystrophic.
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Ectodermal dysplasia, ectrodactyly, and clefting syndrome. Light-colored hair and scalp and earlobe defects are observed. Cleft lip and palate results in a characteristic nasal contour.
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Ectrodactyly observed in an individual with ectodermal dysplasia, ectrodactyly, and clefting syndrome.
