Nasser Rashid Dar ( Departments of Dermatology, Combined Military Hospital, Peshawar. )
Ahsan Hameed ( Military Hospital, Rawalpindi. )
Ashfaq Ahmad Khan ( Military Hospital, Rawalpindi. )
Autoimmunity to type-WI collagen is characterized by autoantibodies predominantly of lgG class to the non-collagenous domain of type-WI collagen present in the anchoring fibrils which bind basement membrane lamina densa to the anchoring plaques in the dermis1. This results in a sublami.na densa split with a blister formation. Type WI collagen autoim.munity is heterogenous in its clinical spectrum presenting as epiderrnaolysis bullosa acquisite (EBA) or a subtype of bullous lupus eiythematosus2. . EBA, the commoner of the presentations, was first described by Elliot in 18953. In its classical form it is characterized by increased skin fragility and non-inflammatory blisters that heal with scarring and milia, occurring predominantly over the trauma prone sites.In addition to its classical form it may clinically mimic bullous pemphigoid or cicatricial pemphigoid. Histologically there is a subepidermal blister with a variable infiltrate. Direct immunoflourescence (DIF) and indirect immunofluorescence (1W) of perilesional salt split skin (SSS), or the substrate respectively demonstrate linear deposition of IgG and sometimes IgA and IgM on the dermal side of the blister. Immunoelectron microscopy shows the imrnunoreactants to be in the subla.mina densa zone. We describe a case of EBA whom we believe is the first confirmed case from Pakistan.
A 46 years old male presented with 3 months histoty of an itchy blistering eruption over the neck, scalp, upper trunk, knees and elbows. He also had a blister on the tongue. On examination tense blisters on normal looking skin were seen on the above mentioned sites. Scarring and milia were also noticed on these sites. A tense haemorrhagic blister was also seen on the lateral aspect of the tongue (Figure 1).
The mucosa was otherwise normal looking. During his stay in the hospital he also developed small vesicular eruption on the forearms in addition to the larger bullae. Systemic examination did not reveal any abnormality. Routine histopathology of a fresh lesion showed asubepidermaiblisterwithadense neutrophilic infiltrate. DIF studies of perilesional and lesional skin revealed linear deposition of IgG and C3 at the dermoepidermal junction (Figure 2)
extending into the floorof the blister cavity (FigUre 3).
DJF of 1.0 molar NaCI split perilesional skin showed the immunoreactants to be confined to the floor of the split. Similar findings were seen in the vesicular lesions of the forearms. IIF was negative. These findings were consistent with the diagnosis of epidermolysis Bullosa Acquisita (EBA). Other investigations including blood counts, urinalysis, chest radiograph, autoimmune profile, liver functions tests and ultrasound abdomen were within normal limits. The patient was given tablet prednisolone 80 mg/day. The vesicular lesions were first to heal followed by the other lesions. After 3 weeks the steroids were tapered to 10mg eveiy alternate day. With this treatment the patient is in rernissionwithanoccasionaiblisterevery now and then. The patient is being followed-up since 10 months.
The diagnostic criteria for EBA are (a) A late onset mechanobullous disorder; (b) No family history of a mechanobullous disorder; (c) A subepidermal blister on routine histopathology; (d) A positive DIF with IgG at the dermoepidermal junction of perilesional skin; (e) deposits localized to lower lamina densa/sublamina densa zone on immunoelectron microscopy; (f) Alternative to (e) are indirect or direct immunofluorescence on SSS and/or western blotting4.
EBA is the prototype and the most common disease associated with autoimmunity to type-VII collagen5. The age of onset vanes widely from early childhood to late adult life, but most cases begin between the fourth and fifth decades. Classical presentation of EBA includes skin fragility, trauma induced blisters and erosions mainly on extensor aspects. The lesions are characteristically non-inflammatory and heal with scarring and milia. Scarring may be absent in the eariy stages of the disease. Mucosal surfaces may be affected including oral, pharyngeal, laiyngeal, nasal, conjunctival, esophageal, genital and urinary bladder rnucosa6. Lesions may resemble dominantdystmphicEB, porphyrias and bullous amyloidosis, but other clinical features and immunofluorescence can differentiate between the various conditions. Othervariants of EBA include a bullous pemphigoid like picture7 or a mixture ofclassicalEBAandbullous pemphigoid. EBA may clinically resemble cicatricial pemphigoid in producing scarring of the mucosae8. Routine histopathology shows a subepidermal blister, which is a feature shared by so many other disease and therefore, is of no diagnostic value. DIF shows deposition mostly of IgG but also C3, IgM, or IgA9,10, at the dermoepidermal junction. About half the patients have no circulating auto-antibodies10 and therefore, the HF on SSS is of no help in such patients. This was the case in ourpatient for whom a modified DIF test was done which can distinguish between EBA and bullous pemphigoid with certainty10. Perilesional skin was incubated in 1M NaCI for 48 hours at 4°C. This procedure separates the epidermis from the dermis at the lamina lucida. The specimen was then frozen and cryosections were treated with reagents for DIF. Because the immunoreactants in EBA are in the sub-lamina densa area, they are seen on the dermal side of the saline induced split. In this patientthe modified DlF showed deposition of lgG and C3 on the derinal side of the split. C3 deposition is not very common in EBA. IIF was negative in this patient because of lack of detectable circulating auto- antibodies.Our patient responded to standard immunosuppressive therapy, but this may not always be the case. Other therapies that may be effective and can be tried in resistant cases include, cyclosporin11, dapsone, coichicine, phenytoin, vitamin E, gold, plasmapheresis12 and intravenous immunoglobulin13. This is the first confirmed report of EBA from this countiy.In the absence of facilities for immunoelectron microscopy and immunoblot analysis, immunofluorescence studies on SSS are the minimum essential for the diagnosis of this disease.
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