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CASE REPORT
Year : 2016  |  Volume : 17  |  Issue : 1  |  Page : 32-34

Pretibial dystrophic epidermolysis bullosa pruriginosa: A rare case report in a child with low intelligent quotient


1 Department of Pathology, JSS Medical College and Hospital, JSS University, Mysore, Karnataka, India
2 Department of Dermatology, Institute of Applied Dermatology, Kasargod, Kerala, India

Date of Web Publication4-Jan-2016

Correspondence Address:
B Vijaya
Department of Pathology, JSS Medical College and Hospital, JSS University, Mysore, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2319-7250.173160

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  Abstract 

Dystrophic epidermolysis bullosa (DEB), a rare form of EB, is characterized by defects in Type VII collagen which is encoded by COL7A1 gene located on chromosome 3p21. A 12-year-old female with low intelligent quotient presented with intensely pruritic multiple violaceous papules which were coalescent at areas on both the shins. Histopathological examination showed epidermis displaying focal thinning. A subepidermal cleft was seen beneath the basement membrane zone. The dermis showed a linear array of keratinous cysts with intervening diffuse lymphohistiocytic infiltrate. Features were suggestive of pretibial DEB. Since it was associated with intense itching, the lesion was termed as pretibial DEB pruriginosa which has combined elements of exclusive pretibial lesions and intense itching. An appropriate clinical history and increased awareness of histopathological features will enable earlier diagnosis and suitable management.

Keywords: Dystrophic, epidermolysis bullosa, pretibial, pruriginosa


How to cite this article:
Vijaya B, Narahari S R, Deka P, Manjunath G V. Pretibial dystrophic epidermolysis bullosa pruriginosa: A rare case report in a child with low intelligent quotient. Indian J Paediatr Dermatol 2016;17:32-4

How to cite this URL:
Vijaya B, Narahari S R, Deka P, Manjunath G V. Pretibial dystrophic epidermolysis bullosa pruriginosa: A rare case report in a child with low intelligent quotient. Indian J Paediatr Dermatol [serial online] 2016 [cited 2020 Jul 9];17:32-4. Available from: http://www.ijpd.in/text.asp?2016/17/1/32/173160


  Introduction Top


Epidermolysis bullosa (EB) is a heterogeneous group of noninflammatory disorders, usually inherited as autosomal dominant or recessive form, characterized by the development of blisters or erosions following the minor trauma of the skin. The clinical presentation ranges from the minimal involvement of the hands and feet to severe, life-threatening, generalized blistering with dystrophic changes, and extra cutaneous involvement.[1] Dystrophic EB (DEB), a rare type, is characterized by defects in Type VII collagen which is encoded by COL7A1 gene located on chromosome 3p21.


  Case Report Top


A 12-year-old female, with low mental intelligent quotient (IQ), presented with intense pruritic lesions on the leg for the past 10 years to the Institute of Applied Dermatology, Kasargod. She had taken multiple treatments, from allopathic to ayurvedic, with no satisfying result. She was also on oral Vitamin B supplements. Routine blood and urine investigations revealed no abnormality.

On examination, multiple violaceous papules which were coalescent at areas were present on the anterior shin [Figure 1]. Lesions were refractory to treatment. The clinical differential diagnoses were lichen planus, lichen amyloidosis, and prurigo. Initial biopsy reported elsewhere revealed appearances of lichen plano-pilaris which was becoming chronic. Follow-up biopsies done revealed features consistent with milia and prurigo nodularis. The third biopsy was sent to the present institution.
Figure 1: Multiple elevated violaceous papules and dusky lesions seen in the pretibial region of the lower limb

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Histopathological examination showed epidermis displaying focal thinning with effacement of rete ridges. A subepidermal cleft without significant inflammatory infiltrate was noted just beneath the basement membrane zone. The roof of the cleft was formed by very minimal dermal tissue just beneath the basement membrane zone. The dermis showed a horizontal linear array of keratinous cysts with intervening diffuse lymphohistiocytic infiltrate [Figure 2]. Pigment incontinence was noted. Histological features were suggestive of a noninflammatory subepidermal bullous disorder favoring a diagnosis of DEB. Long-standing lesions develop milia which were seen as a horizontal linear array of keratinous cysts. Since the lesions were limited to the pretibial region and were intensely pruritic, the final diagnosis offered was pretibial DEB (dermolytic) pruriginosa (Pr).
Figure 2: Subepidermal clefting beneath the basement membrane zone and linear array of keratinous cysts in the superficial dermis with intervening lymphohistiocytic infiltrate (H and E, ×40)

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  Discussion Top


EB are best classified into three subgroups on the basis of the level at which the skin separates. The three subgroups are - intraepidermal/epidermolytic (EB simplex), intra-lamina lucida/junctional (junctional EB), and sub-lamina densa/dermolytic (DEB).[1]

DEB represents a group of inherited disorders that are characterized by defects in Type VII collagen and sub-lamina densa blisters. Type VII collagen is encoded by COL7A1 gene that is located on chromosome 3p21.[2],[3] It is usually inherited as an autosomal dominant or recessive disorder, although an acquired form has also been recognized. The incidence of the hereditary forms is 1:50,000 births; the more severe recessive forms have an incidence of 1:200,000–1:500,000 births.[1]

The rare pretibial variant of DEB was first described by Kuske in 1946.[4] Pretibial EB (PEB) is distinguished from other forms of DEB by a milder phenotype which is characterized by nail dystrophy, scars, and milia that are frequently associated with pruritic, lichenoid papules. The skin lesions preferentially affect the pretibial skin. Intact blisters rarely are observed. Although nail dystrophy presents in childhood, the onset of skin lesions typically occurs after 10 years of age and has been reported to occur as late as the fifth decade.[4] The lesions in the present case started when the patient was 3-year-old and gradually progressed to lichenified papules. The lesions were intensely pruritic to disturb the child who was already slightly disabled with low IQ.

PEB shows appreciable clinical overlap with another rarely described DEB subset, DEB-Pr. Several authors have suggested these conditions may represent the same disease.[5],[6] The case in the present study had exclusive pretibial lesions with associated intense pruritis, and hence it was labeled as pretibial DEB-Pr.

The incidence of PEB is unknown. It may be more common than suspected as it can be misdiagnosed as other inflammatory diseases.[7] This has happened in the present case also where earlier biopsies were misdiagnosed as lichen plano-pilaris, lichen planus, and prurigo nodularis. Inheritance of both PEB and DEB-Pr is autosomal dominant, although sporadic, and compound heterozygous cases have been described.[5],[8] On several studies, mutational analysis have shown glycine substitution mutations in COL7A1 in both variants.[8]

Histologically, many studies have shown that biopsies from the lesions studied show subepidermal blisters and superficial dermal fibrosis within which multiple small cysts lined by keratinizing epithelium are seen.[3],[9] When the level of clefting was observed carefully in the present case, the roof of the cleft was seen just beneath the basement membrane zone with a minimal amount of dermal tissue. This substantiates the pathology in the Type VII collagen in the region of anchoring fibrils. The dermis may show moderately dense lymphocytic infiltrate. The keratinous cysts have been linked to be of eccrine origin.[10]

The mainstay of treatment for this condition includes prevention of trauma and local wound care. Use of cyclosporine, thalidomide, and topical tacrolimus for the treatment of pruritus associated with the DEB-Pr has been recommended by many studies. Recent advances in the treatment of junctional EB by transplantation of genetically modified epidermal stem cells and successful gene expression repair by spliceosome-mediated RNA trans-splicing in EB simplex promise to revolutionize the treatment of EB.[3]


  Conclusion Top


Pretibial DEB with an element of intense pruritis may be a distinct entity where in the lesions are exclusively pretibial and highly pruritic. The prevalence of papular itchy lichenoid lesions, signs of scratching, and paucity of blisters at the time of clinical examination may result in incorrect diagnosis and treatment. An appropriate clinical history and increased awareness of histopathological features will enable earlier diagnosis and suitable management. This rare case of pretibial DEB with intense pruritis occurring in a child with low mental IQ all the more raises the question of means of alleviating the pruritis which may cause secondary changes and mask the true nature of the lesion.

Acknowledgment

We acknowledge Dr. Guruprasad Aggithaya, Institute of Applied Dermatology, Kasargod for providing the clinical inputs.

Financial Support and Sponsorship

Nil.

Conflicts of Interest

There are no conflicts of interest.

 
  References Top

1.
Weedon D, editor. The vesiculobullous reaction pattern. In: Weedon's Skin Pathology. 3rd ed. London: Churchill Livingstone; 2010. p. 93-148.  Back to cited text no. 1
    
2.
Naeyaert JM, Nuytinck L, De Bie S, Beele H, Kint A, De Paepe A. Genetic linkage between the collagen Type VII gene COL7A1 and pretibial epidermolysis bullosa with lichenoid features. J Invest Dermatol 1995;104:803-5.  Back to cited text no. 2
    
3.
Rizzo C, Anandasabapathy N, Walters RF, Rosenman K, Kamino H, Prystowsky S, et al. Pretibial epidermolysis bullosa. Dermatol Online J 2008;14:26.  Back to cited text no. 3
    
4.
Kuske H. Epidermolysis traumatic, regionar uber beiden tibiae zur athrophie fuhrend mit dominanter verenbung. Dermatological 1946;91:304.  Back to cited text no. 4
    
5.
Lee JY, Pulkkinen L, Liu HS, Chen YF, Uitto J. A glycine-to-arginine substitution in the triple-helical domain of Type VII collagen in a family with dominant dystrophic epidermolysis bullosa pruriginosa. J Invest Dermatol 1997;108:947-9.  Back to cited text no. 5
    
6.
Bridges AG, Mutasim DF. Pretibial dystrophic epidermolysis bullosa. Cutis 1999;63:329-32.  Back to cited text no. 6
    
7.
Tang WY, Lee KC, Chow TC, Lo KK. Three Hong Kong Chinese cases of pretibial epidermolysis bullosa: a genodermatosis that can masquerade as an acquired inflammatory disease. Clin Exp Dermatol 1999;24:149-53.  Back to cited text no. 7
    
8.
Christiano AM, Lee JY, Chen WJ, LaForgia S, Uitto J. Pretibial epidermolysis bullosa: genetic linkage to COL7A1 and identification of a glycine-to-cysteine substitution in the triple-helical domain of Type VII collagen. Hum Mol Genet 1995;4:1579-83.  Back to cited text no. 8
    
9.
Joshi A, Sah SP. Pretibial epidermolysis bullosa. Indian J Dermatol 2002;47:179-81.  Back to cited text no. 9
  Medknow Journal  
10.
Berk DR, Bayliss SJ. Milia: a review and classification. J Am Acad Dermatol 2008;59:1050-63.  Back to cited text no. 10
    


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  [Figure 1], [Figure 2]



 

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