shingles , also called herpes zoster ( hz ) , is a common viral disease .
psoriasis is another common , chronic relapsing and remitting inflammatory disease that involves the skin and joints with an overall prevalence of 2% to 3% of the world 's population .
koebner phenomenon ( kp ) , also called isomorphic response , is initially referred to the formation of psoriasiform lesions after cutaneous trauma on healthy skin areas of psoriatic patients , and now is extended to the instances that the people who had pre - existing dermatosis develop lesions after trauma or injury .
only a few of psoriatic kp following shingles have been reported in literature , and the kp lesions always occur at healing or healed hz eruptions with a latent period of 1 week to 4 months from the occurrence of shingles in this condition . herein , we report a psoriatic patient in whom kp is occurring at the site of developing hz lesions , and to our knowledge , no similar description has been reported before .
a 30-year - old man was referred with 3-day history of clustered scaly papules on the right chest wall .
the patient had episodes of groups of erythematous papules with shooting pain distributed on his right side of chest alone in the dermatome 9 days ago , which quickly turned into vesicles within 2 days .
he was diagnosed as hz and started on treatment of valaciclovir on the 4 day after the appearance of painful papules , resulting in rapid pain relief after being treated for 2 days .
on the 6 day of the course of disease , the patient found that the vesicles began subsiding and became scaly papules rapidly in situ .
the patient had 7-month history of scalp psoriasis showing good response to topical application of calcipotriol ointment , but he used the medicine irregularly resulting in recurrent lesions sometimes .
he never had kp lesions , and any other associations , since the onset of psoriasis .
cutaneous examination revealed that scaly erythematous papules and plaques located on the scalp and forehead ( figure 1a ) , and groups of clustered erythematous papules with silver scales in the dermatome distributed on the right side of chest wall where the prior hz lesions occurred ( figure 1b , c ) .
no other kinds of lesions were observed elsewhere including limbs , nails , and the trunk except the site where the prior hz eruptions involved .
the patient was diagnosed as kp of psoriasis , and was treated with topical application of clobetasol propionate and calcipotriol compounds , which resulted in excellent response after a week of treatment ( figure 1d ) . on 1 year of follow - up , the patient had occasional recurrence of psoriasis when the treatment was stopped ; no new zosteriform eruptions reoccurred .
interestingly , the recurrent lesions occurred only on the scalp and the areas of prior shingles each time ( figure 1e , f ) .
histology from thoracic lesion showed regular epidermal hyperplasia with test - tube - shaped rete ridges , thinning over some derma papilae , acanthosis , parakeratosis , and lack of granular layer ( figure 2 ) .
( b , c ) groups of clustered papules with silver scales in the dermatome distributed on the right side of chest wall where the previous developing hz involved .
( d ) the scaly papules relived markedly after 1 week of topical application of clobetasol propionate and calcipotriol compounds .
( e , f ) the recurrent psoriatic lesions on the areas of the previous shingle on 7 months of follow - up .
histology shows regular epidermal hyperplasia with test - tube - shaped rete ridges , thinning over some derma papilae , acanthosis , parakeratosis , and lack of granular layer .
the present patient had groups of painful papules and vesicles distributed in the dermatome on unilateral chest wall ; hz can be diagnosed clinically although without laboratory support . generally , the natural history of hz is that its initial lesions appear as erythematous papules , which turn into vesicle within 12 to 24  hours .
the vesicles of hz progress into pustules in about 3 days and form scabs over the next 7 to 10 days .
the inflammatory lesions within the involved dermatome after hz have been rarely described , but the lesions are present as flat topped lesions or annular papules , and usually appear within a month with the absence of scales .
it was found in the present patient that his blisters became scaly papules on the 6 day during the course ; we considered that the scaly papules formed during developing stage of hz rather than recovering time .
based on the psoriasis history and the present clinical features : the developing painful papules and vesicles became scaly papules with underlying bleeding points , which showed excellent response to topical application of clobetasol propionate and calcipotriol compounds , we considered that the present scaly papules are kp of psoriasis subsequent to developing hz rather than to healing hz lesions themselves , although slight scarring may occur in patient with hz at the site the blisters have been .
the diseases tending to koebnerization include psoriasis , vitiligo , lichen planus , darier disease , bullous dermatoses , and so on .
the provoking factors for kp include trauma , burns , friction , insect bites , surgical incision , as well as dermatoses and therapeutics , such as hz , syphilis , and ultraviolet b treatment , and even the cupping therapy , a kind of traditional chinese medicine .
season , disease severity , trauma on skin , scar tissue , and emotional stress can also trigger kp in patient with psoriasis .
the duration from injury to occurrence of kp may range from 3 days to years , but in general , it is between 10 and 20 days .
only a few cases have described their kp lesions of psoriasis at the site of healed or healing hz as well as varicella involved . in the present patient ,
kp eruptions occurred at the areas of developing hz lesions with only 6-day interval from the painful chest and 4 days from the appearance of vesicles , which , to our knowledge , has never been reported before .
other interesting entity is that , on a year of follow - up , the recurrent psoriatic lesions located only on the scalp and the healed hz areas . as the recurrent thoracic lesions occurred synchronously with the scalp 's each time , we considered them to be relapsing psoriasis rather than recurrently psoriatic kp on healed hz .
however , the reason why the recurrent psoriasis was localized to the areas mentioned above was unknown .
although kp is a common condition , its pathogenesis is not fully understood yet , but may involve cytokines , stress proteins , adhesion molecules , and autoantigens .
it is considered that nerve growth factor , tumor necrosis factor- , substance p as well as interleukin-1 play important roles in the pathomechanism of koebnerization in psoriasis .
the occurrence of psoriatic koebnerization at the site of shingles and varicella was considered to be mediated by neuropeptides such as substance p. substance p , an endogenous neuropeptide being potentiated by viral infection and acting as a chemomediator of nociceptive impulse from periphery to central nervous system , plays an important role in the hz - associated pain .
viral infection can potentiate the effect of substance p by decreasing the degradation of its breakdown enzyme .
we speculate that substance p may play an important role in the present kp , although the exact mechanisms remain unknown .
interestingly , we soon met another typical shingles patient with prior severe psoriatic lesions over his whole body , but neither his prior shingles involved areas nor other areas occurred kp during 6 months of follow - up .
it suggests that kp occurs at the site of hz lesions in not all the psoriatic patients with shingles . as a matter of fact , although both psoriasis and shingles are common diseases , few of psoriatic kp subsequent to hz have been reported .
koebner lesions should be treated in the same way as the associated dermatosis , as our present patient did .
the present patient was notable because the psoriatic kp lesions occurred at the site of developing hz , and the recurrent psoriasis localized only on the primarily areas and healed shingles areas .
both psoriasis and shingles are common cutaneous diseases . about 25% of the patients with psoriasis
not only healing and healed shingles can cause kp in psoriasis , but also developing shingles can cause such a condition at the site of hz lesions .
the authors thank professor rashmi sarkar , md , department of dermatology , maulana azad medical college and lnjp hospital , new delhi , india , for her assistance in revising the manuscript ; and also thank the patient participating in the present study .
 abstractboth shingles and psoriasis are common cutaneous diseases . 
 about 25% of the psoriatic patients develop koebner phenomenon ( kp ) after various injuries , and in rare instance , kp may occur at the site of healed or healing shingles.we report a 30-year - old man with 7-month history of scalp psoriasis who developed kp at the areas of developing shingles . 
 cutaneous examination revealed scaly erythematous papules and plaques located on the scalp and forehead , and groups of clustered erythematous papules with silver scales in the dermatome distributed on the right side of chest wall the prior herpes zoster lesions involved . 
 after removal of the scales on the papules , underlying bleeding points were present.the lesions on chest had good response to anti - psoriatic therapies , as the lesions on scalp did . 
 after a year of follow - up , recurrent psoriasis occurred , but the lesions were located only on the scalp , and the areas of prior occurrence of shingles , because of which we considered diagnosis of recurrent psoriasis rather than relapsing kp for the chest lesions.not only the healing and healed shingles can trigger kp in psoriasis , but also the developing shingles can cause psoriatic kp at the site of herpes zoster lesions . 
INTRODUCTION
CASE PRESENTATION
DISCUSSION
CONCLUSIONS
ACKNOWLEDGMENTS