bullous pemphigoid ( bp ) , an autoimmune bullous disorder due to antibodies against hemidesmosomal proteins namely bp antigen 1 ( bpag1 ) and bp antigen 2 ( bpag2 ) , usually affects the elderly , predominantly as flexural bullae over limbs and abdomen . dyshidrosiform pemphigoid ( dp ) , a rare variant of localized bp , presents over the palms and soles akin to dyshidrosiform dermatitis . an association between neurological diseases ( stroke , dementia , parkinsonism , epilepsy , etc . ) and subsequent development of bp may exist , as autoantibodies against the exposed neuronal antigen ( bpag1-n ) , an alternating spliced form of epithelial bpag1 ( bpag1-e ) that stabilizes the cytoskeleton of sensory neurons , may cross - react with the epithelial antigen ( bpag1-e ) . herein we report the development of dp in a 91-year - old female patient of parkinsonism , enunciating its pathogenesis . a debilitated , non - ambulatory female aged 91 years , known case of parkinsonism since 2 years , presented to us with the history of appearance of multiple blisters over palms and soles since one month . neurological examination revealed mask like facies , glabellar tap , pill rolling tremors of the right hand , cogwheel rigidity and hypertonia of limbs . lateral and palmoplantar aspects of hands [ figure 1 ] and feet [ figure 2 ] showed dark brown encrusted erosions and a few tense clear bullae with negative nikolsky- and asboe - hansen signs . histopathological examination findings of subepidermal bulla containing eosinophilic infiltrate [ figure 3 ] in the lesional skin and igg at dermoepidermal junction ( dej ) on direct immunofluorescense [ figure 4 ] confirmed our clinical suspicion of bp . peripheral blood smear and ultrasonography abdomen were normal . advanced imaging studies could not be carried out due to kyphoscoliosis , chest x - ray evidence of scoliosis to the right and her confinement to the wheelchair she insisted to go home on discharge and passed away a month later due to gastrointestinal bleeding . healed lesions with hyperpigmentation in between fingers of right hand and over right palm bullae over the sole of the left foot lesional skin biopsy showing ( a ) subepidermal blisters predominantly containing eosinophilic infiltrates ( h and e , 10 ) , ( b ) eosinophilic infiltrates ( h and e , 40 ) direct immunofluorescence showing linear deposition of igg in the basement membrane zone ( 400 ) bp , a subepidermal immunobullous dermatosis , has characteristic linear immune deposits of igg and c3 at the dej . the median age of onset is 65 years and incidence ranges between 0.2 and 3 per 100,000 person years . classic bp has generalized large , tense blisters with serous or hemorrhagic fluid arising over normal or erythematous skin , predominantly of flexures , abdomen and thighs . while some patients develop blisters after persistent urticarial lesions , others continue to have urticarial lesions only . several variants ( viz . , vesicular , vegetative , nodular , localized , dyshidrosiform , erythrodermic , etc . ) have been described . rarely , nodules resembling prurigo nodularis and blisters originating on normal - appearing or nodular skin indicate nodular bp . infrequently , the variant of localized bp occurs mainly over the legs , though it has been documented over oral and vulvar regions and also following radiotherapy , surgery , burns , etc . dp , first described by levine et al . in 1979 , is a rare form of localized bp similar to dyshidrosiform dermatitis . the mechanism of localization is still unclear . at the molecular level , bp is characterized by the tissue - bound and circulating igg autoantibodies against the two hemidesmosomal antigens , bpag1 ( 230 kd ) intracellularly and bpag2 ( 180 kd or type xvii collagen ) the transmembrane protein . this igg disrupts dej , by activating complement and causing inflammation and may also directly interfere with the function of hemidesmosomes . bpag1-e , the epithelial isoform that anchors intermediate filaments to the hemidesmosomes and bpag1-n , the neuronal isoform that organizes the neuronal cytoskeleton by binding the neurofilament triplet proteins to the microfilaments , share high homology . bpag1-n , usually protected from antibody recognition , might get uncovered during an acute phase of neurodegeneration , generating autoantibodies that can cause cutaneous damage due to cross - reactivity . multiple microtrauma , microvascular pathology or local inflammation seen on magnetic resonance imaging during the acute phase of neurodegenerative diseases may abolish the brain 's immunological privilege due to the damaged blood - brain barrier . the peripheral immune system might activate itself against the neuronal antigens magnifying damage to the central nervous system . this hypothesis was also supported by the association between the dystonin gene , encoding for the neuronal isoform of bpag1 and degenerative neurological disease in mice . alternatively , factors such as immobility and drugs associated with the management of previous neurological disorders may trigger bp . a recent study reported an associated occurrence of bp in 21% cases of neurological disorder ( 8% stroke , 7% dementia , 3% parkinsonism , 2% epilepsy and 1% multiple sclerosis ) of more than a year 's duration ; however , in none of the cases bp preceded a neurological disorder thereby proving that the exposure of the neuronal antigen can be a causative factor in the later onset of bp in these patients . hence , novel interventions ( e.g. targeting bpag1-n ) based on the immune association between neurodegeneration and bp may become available in the future . to the best of our knowledge , none of the earlier described 21 cases of dp in the world literature have been from india ; our present case of dp in an extremely aged female of parkinsonism  first such from india - emphasizes the imperative requirement of a thorough search for any underlying neurodegenerative disease in all elderly patients of bp .
dyshidrosiform pemphigoid is a rare variant of bullous pemphigoid localized to the hands and feet whose characteristic subepidermal blisters develop as a result of binding of the igg autoantibodies to intracellular plaque and extracellular face of the hemidesmosome recognizing a 230-kda plakin molecule ( bp230 , bpag1or bpag1e ) and a 180-kda transmembrane protein . 
 neurodegenerative processes ( viz . , stroke , dementia , parkinsonism , epilepsy , etc ) uncover bpag1-n , an alternatively spliced form of bpag1-e that stabilizes the cytoskeleton of sensory neurons , generating autoantibodies that may subsequently lead to bp by cross - reacting with bpag1-e . 
 we present a patient with parkinsonism who later developed blisters , erosions and crusts localized to the palms and soles , confirmed histopathologically as bullous pemphigoid . to the best of our knowledge , 
 ours is the first case report from india wherein parkinsonism - generated autoantibodies led to the development of dyshidrosiform pemphigoid due to their cross - reactivity with bpag1-e .