Year : 2005 | Volume
: 50 | Issue : 3 | Page : 158--160
Epidermolysis bullosa pruriginosa
Suruchi Puri, Soni Nanda, Chander Grover, B SN Reddy
Department of Dermatology and STD, Maulana Azad Medical College and Lok Nayak Hospital, New Delhi-110 002, India
Department of Dermatology and STD, Maulana Azad Medical College and Lok Nayak Hospital, New Delhi-110 002
Epidermolysis bullosa (EB) pruriginosa is a rare distinct variant of dystrophic EB. It is characterized by extremely pruritic, lichenified or nodular lesions predominantly over legs, milia formation and albopapuloid lesions on the trunk. Toe nail dystrophy is a consistent finding in adult patients. The rarity of intact blisters, prominent nature of some of the scars and the marked lichenification with severe pruritus lead to a confusion with commoner disorders, like lichen simplex chronicus, lichen planus hypertrophicus and dermatitis artefacta. We present a rare and interesting case of EB pruriginosa where the diagnosis was confirmed with help of characteristic histopathology.
|How to cite this article:|
Puri S, Nanda S, Grover C, Reddy B S. Epidermolysis bullosa pruriginosa.Indian J Dermatol 2005;50:158-160
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Puri S, Nanda S, Grover C, Reddy B S. Epidermolysis bullosa pruriginosa. Indian J Dermatol [serial online] 2005 [cited 2021 Sep 24 ];50:158-160
Available from: https://www.e-ijd.org/text.asp?2005/50/3/158/18932
A 50 year old man presented to us with complaints of symmetrical, itchy, raised skin lesions over the limbs since childhood. The lesions were excrusiatingly itchy to disrupt the daily activities and sleep of the patient. There was a history of occasional fluid filled lesions following trauma and a history of loss of all toe nails. No history of atopy, food or drug allergy, nor any systemic or cutaneus cause for severe pruritus was detectable. Similar history was present in the other 2 brothers and in his father. Patient had taken treatment in the form of both topical and systemic therapies from many private practitioners and government hospitals with no relief.
Examination revealed a middle aged man of normal built and intelligence. Mucocutaneus examination showed numerous excoriated and lichenified papules with associated scarring and milia formation in a striking linear configuration over extensor aspects of both forearms and shins [Figure 1]. There was complete sparing of the face, neck and major flexures. Blisters which were seen only occasionally on physical examination were flaccid, present over a normal skin base and dozed out watery fluid on puncturing. There was anonychia of all the toe nails [Figure 2]. Finger nails, hair and mucosa showed no abnormality. Rest of the systemic examination was within normal limits.
Hemogram, renal function, liver function, serum electrolytes were all normal. Autoantibody screening was also negative. Histopathological examination of the lichenified papule revealed hyperkeratosis, acanthosis, subepithelial split and a moderate mixed inflammatory infiltrate in the dermis.
Based on the classical history, examination findings and histopathological report of the patient, a diagnosis of epidermolysis bullosa (EB) pruriginosa /pretibial EB was established. The prognosis was explained to the patient and he was given symptomatic treatment.
EB pruriginosa is a type of dystrophic EB termed by McGrath in 1994, though a number reports of similar condition have appeared in literature since 1946.- Both autosomal dominant and recessive patterns have been recognized. Genetic linkage studies in families with dominant and recessive dystrophic EB have confirmed tight linkage to the type VII collagen gene. Structural protein abnormalities of type VII collagen either in the helical portion or the globular end domains suggesting the possible influence of type VII collagen gene, along with some other factor, might be responsible for causing a variety of abnormalities in the collagen helix assembly dimer formation or lateral aggregation, thus resulting in a diversity of clinical features., Recent molecular analysis studies have revealed a glycine substitution within the triple helical collagenous domain of the type VII molecule, to be exclusively associated with the dominant dystrophic EB, and EB pruirigunosa. 
The condition is characterised by extremely pruritic linear lichenified or nodular prurigo-like lesions predominantly over legs, occasional trauma-induced blistering, excoriations, milia, nail dystrophy and in some case albopapuloid lesions on the trunk with onset at birth (with only mild acral blistering) or during infancy or childhood. The exact cause of pruritus in this condition is unknown. Possibly, the exposure of type VII collagen is known to trigger the activation of the kinin cascade. Bradykinin possibly interacting with other mediators might be responsible for the severe pruritus. Pruritus is however a recognised feature of all types of EB, though it is particularly troublesome in the Dowling-Meara form of EB simplex, besides being noted in dystrophic and junctional EB. Onset of itching at childhood similar to our case was noticed in 5 out of 8 patients described by McGrath, et al and in Kennedy's patient as well. Apart from the dystrophic scarring with milia, toe nail dystrophy is a consistent finding in adult patients.,
Histologically, a split may be evident at the dermoepidermal junction, although frank blisters are rarely seen. Ultrastructurally, there is a sublamina densa level of blister formation and quantitative or qualitative changes in anchoring fibrils at the dermoepidermal junction. Reduction in anchoring fibril number is found in lesional, perilesional and non- lesional skin of patients with EB pruriginosa.
In the present case, diagnosis was established on the basis of presence of lesions since childhood, intensely itchy lesions over extensors of upper and lower limbs, loss of toe nails, a positive family history, presence of lichenified papules in a linear fashion with associated scarring, milia formation and occasional blisters and normal hair and mucosa with the histopathology revealing a subepidermal cleft.
The commoner non-EB dermatoses form important differential diagnosis for the condition. These include lichen planus hypertrophicus, lichen simplex chronicus, cutaneous amyloidosis, Neekam's disease and dermatitis artefacta. The rarity of intact blisters, prominent nature of some of the scars, and the marked lichenification with severe pruritus shows overlap with these commoner non-EB related dermatoses. None of the above lesions would reveal a subepidermal cleft on histopathology.
The condition is a genodermatosis and there is no definite treatment to date. Symptomatic treatment for pruritus includes use of oral antihistaminics, short course of low dose oral steroids, oral antibiotics to treat the secondary infection. Retinoids (etretinate), and thalidomide have been tried but lesions recur after the stoppage of the therapy. Surgical treatment in the form of dermabrasion, excision and grafting can be performed but new lesions continue to appear. Gene therapy and genetic counselling are possibly the most promising approach to a patient with this condition.
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