Rapp Hodgkin Syndrome

Ectodermal dysplasias are a heterogeneous group of disorders resulting from abnormalities of structures derived from embryonic ectoderm (skin, teeth, and appendage). Rapp Hodgkin Syndrome (RHS) is a type of anhidrotic ectodermal dysplasia, which was described by Rapp and Hodgkin in 1968.[1] This syndrome is characterized by anhidrotic ectodermal dysplasia, cleft lip, and cleft palate. Other features, which have been described by various authors include coarse and wiry hairs, small mouth, narrow nose, oligodontia or anodontia, conical teeth, anonychia, hyponychia, narrow or dystrophic nails, lacrimal duct abnormalities, ear and ear canal abnormalities, and genitourinary abnormalities.[2,3] It has autosomal dominant inheritance. Here, we report a rare sporadic case of RHS with characteristic manifestations.

A 4-year-old male child, born to unrelated parents, presented with complaints of dark discoloration of skin, inability to sweat, and heat intolerance. Parents also complained that the child had teeth loss, facial deformity, and greying of hairs. There was no history of similar complaints in the family. Dermatological examination revealed dry, hyperpigmented skin with generalized distribution of follicular papules, sparse eyebrows and eyelashes, epiphora, microtia, and orofacial clefting [Figures 1a and b]. He also had coarse, dry and gray hairs, scalp dermatitis, hypodontia, mid facial hypoplasia, hyponychia, and hypospadias [Figure 1c and d]. Histopathological examination of skin revealed hyperkeratosis, acanthosis, follicular plugging, increased pigmentation of basal layer, pigmentary incontinence, perivascular inflammatory infiltrate, and decreased pilosebaceous follicles [Figure 2a and b]. Trichoscopy revealed varying diameters of hair shafts, hair shaft at variable angles, and most follicles containing single hair and gray hairs. Trichoscopic features were consistent with pili torti [Figure 2c and d]. In view of anhidrotic ectodermal dysplasia associated with orofacial clefting, hypodontia, microtia, genitourinary abnormalities, lacrimal duct anomaly, and hair involvement, the diagnosis of RHS was made.

Figure 1.

Repaired cleft lip and palate, epiphora; (b) hypodontia; (c) Scalp dermatitis; (d) Hypospadias

Figure 2.

(a) Histopathology of skin – Hyperkeratosis, acanthosis, follicular plugging (H and E. 4×); (b) Histopathology of skin – Increased pigmentation of basal layer, superficial perivascular infiltrate, and decreased pilosebaceous follicles (H and E, 10×); (c, d) Dry trichoscopy using polarised light (Heine Delta 20) – varying diameters of hair shafts, hair shaft at variable angles, most follicles, containing single hair and gray hairs – consistent with pili torti

RHS is a rare ectodermal dysplasia with characteristic cutaneous features, however, it has been disputed whether it is a distinct clinical entity or part of EEC syndrome (ectrodactyly, ectodermal dysplasia, and cleft lip/palate syndrome).[4] EEC syndrome results from a mutation in TP63 gene[5] and recently it has been found that similar mutation can also be seen in cases of RHS, thereby suggesting that RHS is a part of EEC syndrome.[6]

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Conflicts of interest

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