|Year : 2015 | Volume
| Issue : 4 | Page : 203-206
Pretibial epidermolysis bullosa in a Kashmiri girl
Yasmeen J Bhat1, Iffat Hassan1, Peerzada Sajad1, Rohi Wani2
1 Department of Dermatology, STD and Leprosy, Government Medical College, Srinagar, Jammu and Kashmir, India
2 Department of Pathology, Government Medical College, Srinagar, Jammu and Kashmir, India
|Date of Web Publication||24-Sep-2015|
Yasmeen J Bhat
Department of Dermatology, STD and Leprosy, Government Medical College, Srinagar, Jammu and Kashmir
Source of Support: None, Conflict of Interest: None
Pretibial epidermolysis bullosa (EB) is a rare type of dystrophic EB characterized by itching, blisters, atrophy, and scarring localized to the shins. The term pretibial is used because of the localization of lesions to the shins. It has been rarely reported in the literature. There is no specific treatment for any form of EB, and the mainstay of clinical management is based on protection and avoidance of provoking factors. We report a case of pretibial EB in a 15-year-old ethnic Kashmiri girl who presented with a history of blisters over legs of 3 years duration.
Keywords: Dystrophic epidermolysis bullosa, epidermolysis bullosa, pretibial
|How to cite this article:|
Bhat YJ, Hassan I, Sajad P, Wani R. Pretibial epidermolysis bullosa in a Kashmiri girl. Indian J Paediatr Dermatol 2015;16:203-6
|How to cite this URL:|
Bhat YJ, Hassan I, Sajad P, Wani R. Pretibial epidermolysis bullosa in a Kashmiri girl. Indian J Paediatr Dermatol [serial online] 2015 [cited 2021 Jul 25];16:203-6. Available from: https://www.ijpd.in/text.asp?2015/16/4/203/165613
| Introduction|| |
Pretibial epidermolysis bullosa (EB) is a rare subtype of dystrophic EB (DEB) characterized by the development of blisters, erosions, atrophy, and scarring predominantly involving the pretibial region of lower legs. , It is caused by mutations within the Type VII collagen gene (COL7A1) which lead to an alteration of function or to reduced amounts of collagen VII which impairs its assembly into anchoring fibrils.  This in turn causes reduced skin resistance to minor trauma. The disease follows an autosomal dominant or an autosomal recessive pattern of inheritance. Only 40 families or sporadic cases have been reported till date.  The disease usually manifests at birth or during infancy, but the onset may also be delayed until the adolescence. It involves almost exclusively the anterior lower legs (pretibial areas and feet), the hands and nails. The individual lesions, which tend to be papular or plaque-like, are often voilaceous, and occasionally pruritic suggesting the clinical diagnosis of lichen planus. The healing of blisters is associated with hypertrophic scarring and milia formation. Dystrophy of both fingernails and toenails is a characteristic associated feature. Pterygium formation, however, is unusual, thus excluding the diagnosis of lichen planus. ,
| Case report|| |
A 15-year-old ethnic Kashmiri girl, the product of nonconsanguinous marriage presented with a history of mild itching and fluid-filled lesions on the front of both legs of 3 years duration with no prodromal symptoms. The lesions would rupture approximately after 3-4 days time leading to crust formation followed by scarring. There was no history of mucosal lesions, photosensitivity, and joint pains. There was no history of such lesions in other two siblings and her parents. However, there was a history of generalized bullous eruption and scarring in two of her paternal cousins since birth. On examination, there were multiple, erythematous, crusted, and voilaceous plaques of varying sizes ranging from 1 cm to 6 cm on the front of both legs, knees, and feet [Figure 1]. Nikolsky's sign was negative. Shiny atrophic scars were also present on knees and front of both legs [Figure 2]. The nails of 2 nd and 3 rd toenails of both feet were dystrophic [Figure 3]. There were no such lesions on rest of the body. All the mucosae, teeth, hair, palms and soles, and scalp were normal. The baseline investigations were normal. Skin biopsy for histopathological and direct immunofluorescent examination was done. Histopathology revealed a subepidermal blister with minimal inflammatory infiltrate and dermal edema [Figure 4]. Direct immunofluorescence of adjacent non-lesional skin was negative. Electron microscopy was not possible as the facility is not available in our institute. A diagnosis of DEB of the pretibial type was thus made. DEB pruriginosa and albopapuloid variant of DEB (Weber-Cockayne type) were considered in the differential diagnosis.
|Figure 4: Subepidermal split with inflammatory infiltrate and dermal edema (H and E ×40)|
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| Discussion|| |
Epidermolysis bullosa comprises a group of genetically determined skin fragility disorders characterized by blistering of the skin and mucosae following mild mechanical trauma. The incidence and prevalence of EB are estimated to be 19.60/million live births and 8.22/million population. There is no gender, racial, ethnic or geographical predilection for EB. Epidermolysis bullosa is divided into epidermolytic type (suprabasal and basal EB simplex types), junctional type (lamina lucidolytic), dermolytic type (dominant and recessive dystrophic types) and mixed types depending on the level of cleavage and underlying molecular abnormalities.  The investigations which are used for the diagnosis are skin biopsy, electron microscopy, antigen mapping, antibody probes, and DNA-based techniques. There is no specific treatment for any form of EB, and the mainstay of clinical management is based on protection and avoidance of provoking factors. Autologous split-thickness skin grafts have been used for the treatment of pretibial EB and in the treatment of chronic ulcers or erosions in patients with generalized recessive dystrophic EB. ,,
The dystrophic forms of EB are characterized by skin fragility, blistering, scarring, nail changes, and milia formation. There are both autosomal dominant and recessive forms, which are caused by mutations in a single gene, COL7A1, which encodes the anchoring fibril protein, Type VII collagen. Ultrastructurally, the level of blistering or tissue cleavage in all dystrophic forms of EB is immediately below the lamina densa of the epidermal basement membrane, at a site normally occupied by anchoring fibrils. Electron microscopy and immunoelectron microscopy have shown that anchoring fibrils in dystrophic EB are reduced in number, morphologically altered or are completely absent.  Immunofluorescence staining of the skin of patients using antitype VII collagen antibodies showed that the normal bright linear staining is absent in severe generalized recessive DEB, but present in dominant DEB. In the milder or more localized form of recessive DEB, such as pretibial variant the immunoreactivity may be attenuated or normal in intensity. Genetic counseling and gene therapy probably remain the most promising approaches. As in other forms of dystrophic EB, a prenatal diagnosis is possible by finding a cleft/blister formation at dermo-epidermal junction by light microscopy or more precisely by electron microscopy in fetal skin biopsy taken at 15-18 weeks' of gestation. Similarly, rapid prenatal diagnosis may be possible by using LH 7:2 monoclonal antibody staining of skin samples obtained from 18 weeks fetus at risk. ,,
In 1946, Kuske reported a patient with itching, blisters, atrophy, and scarring on the shins. There were further reports of similar patients. In one family with a dominant transmission of the disease, the clinical features were variable. Several authors have referred to this condition as pretibial EB, given the tendency for the lesions to develop in the pretibial areas. Lesions are usually voilaceous, mimicking lichen planus. Nails on both hands and feet tend to be dystrophic. The condition is an autosomal dominant one.  Our patient also seemed to have an autosomal dominant inheritance, being a product of nonconsangineous marriage and history of bullous lesions in cousins.
Epidermolysis bullosa pruriginosa is a rare and distinct clinical subtype of dystrophic EB which was described for the first time in 1994. It is characterized by skin fragility, blistering, scarring, and milia formation, nodular prurigo like and lichenoid lesions. Clinically, these features overlap with those of the pretibial type of DEB. However, all the reported cases suggest a distinct nature and clinical spectrum of this disorder. Furthermore, the lesions in EB pruriginosa are more widespread, always associated with intense pruritus, and the onset of disorder is often late during adulthood.  Other closely mimicking nonbullous dermatosis such as nodular prurigo, lichen simplex chronicus, dermatitis artefacta, lichen planus hypertrophicus, lichen amyloidosis, and hypertrophic scars have distinct clinicopathological features, and all these disorders do not show subepidermal clefting on histopathology.
The autosomal dominant forms of DEB (DDEB) demonstrate relatively mild blistering tendency associated with nail dystrophy. Some DDEB patients present with whitish dermal papules, which are called as albopapuloid lesions. On the basis of the presence or absence of these albopapuloid lesions, DDEB has been conventionally divided into Pasini and Cockayne-Touraine variants, respectively. Type VII collagen gene, COL7A1, is the candidate gene for mutations in DDEB. The blistering tendency in albopapuloid variant persists throughout childhood, but the frequency of blister formation diminishes gradually with age. Nails are dystrophic but less than the pretibial type of EB. Multiple, white-pink papules reminiscent of lichen planus, but without pigmentation or striae of Wickham, located on the extremities and the trunk as well as on the back are a typical feature of the albopapuloid variant which were absent in our case. The papules typically contain milia. Lichenification and hyperkeratosis which is typically seen in the pruriginosa variant of DDEB is absent in albopapuloid variant of DDEB as well as in the pretibial type of EB. 
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]