the dermal vascular changes have been evaluated by electron microscopy and shown to be due to change from arterial - type vessels to venules . the vascular changes may also precede the epidermal alterations , as shown in some studies . morphometric evaluation of dermal vasculature in psoriasis has shown increased endothelial and luminal volume of vessels compared to control subjects . studies utilizing native capillaroscopy have demonstrated reduction in microvessel density and length density after pulsed dye laser treatment . however , none of the earlier studies have compared vascular morphology between psoriasis and psoriasiform dermatitis . this study was aimed at evaluating the morphometric parameters of papillary dermal vessels in psoriasis and to compare these with psoriasiform lesions . in this study , skin biopsies from 25 cases of psoriasis and 25 of psoriasiform lesions were included . the diagnosis of psoriasis was confirmed on the basis of clinical features ( pink to red papules with fine silvery scales and positive auspitz sign ) in conjunction with characteristic histologic changes . the latter included : regular acanthosis with club - shaped rete ridges , suprapapillary epidermal thinning , hypogranulosis , confluent parakeratosis , spongiform pustules of kogoj and/or munro microabscesses . psoriasiform lesions included in the study were : endogenous eczema : nine cases , hyperkeratotic eczema : seven cases , seborrheic dermatitis : three cases , nummular eczema : 2 cases , and one case each of allergic contact dermatitis , irritant contact dermatitis , lichen simplex chronicus , and pityriasis rosea . serial sections were stained for cd34 ( biogenex , usa ) using the standard streptavidin - biotin - peroxidase method . using image analysis software , the number , area , and length density of microvessel in dermal papillae were calculated from the cd34-stained sections . the microvessel density was calculated as number of vessels per unit ( mm ) papillary dermal area . length density of microvessel ( mm / mm or mm ) was calculated by superimposition of cycloid grid on vertical sections of skin biopsy [ figure 1 ] . microvessel length density is defined as length of microvessels per unit dermal area and was calculated as 2i / l , where i refer to the number of intersections and l is total length of test lines . ratio of microvessel area to the papillary dermal area was also calculated in both the groups included . photomicrograph showing immunostaining for cd34 in a case of psoriasis with superimposed cycloid grid for morphometry ( lsab , 200 ) appropriate statistical analysis was performed on the morphometric parameters between the two groups . on light microscopic evaluation of cd34-stained sections , biopsies from psoriasis showed much greater microvascular staining in the papillary dermis compared to psoriasiform dermatitis [ figure 2 ] . photomicrograph demonstrating the dermal vessels in psoriasis ( a , lsab , 200 ) and psoriasiform dermatitis ( b , lsab 200 ) morphometric analysis showed that length density of microvessels was significantly higher in psoriasis ( 3.731.45 mm ) compared to psoriasiform lesions ( 2.991.99 mm , p value 0.03 ) . microvessel density , i.e. , number of vessels per unit dermal area , was also higher in psoriasis ( 71.2840.05 ) than psoriasiform lesions ( 62.732.03 ) , though the difference was not statistically significant . in contrast to these parameters , the ratio of microvessel area to papillary dermal area was similar in psoriasis ( 0.130.07 ) and psoriasiform lesions ( 0.140.11 ) [ table 1 ] . comparative analysis of dermal microvasculature in psoriasis and psoriasiform dermatitis these three morphometric vascular parameters are depicted in scatter plots [ figures 3a  c ] . ( a ) scatter plots of vessel area per unit papillary dermal area ; ( b ) microvessel density ; and ( c ) length density in psoriasis and psoriasiform dermatitis psoriasis is an autoimmune disease affecting people of all ages , though there is a tendency for onset in early adulthood in patients with genetic transmission . apart from epidermal changes , skin biopsies from patients with psoriasis demonstrate alterations in papillary dermis such as edema and dilated tortuous capillaries . these dilated capillaries are the source of bleeding points generated by gentle scraping of skin ( auspitz sign ) . few ultrastructural studies have shown that dermal capillaries in psoriasis have a wider lumen , bridged fenestrations with edematous areas in endothelial cytoplasm . these changes also correlate with enhanced cutaneous blood flow , including in the perilesional clinically unaffected skin . it has been proposed that vascular changes in the papillary dermis , including enhanced expression of adhesion molecules , permit leukocyte adhesion and assist in the establishment of inflammatory response . barton et al . , in their study , demonstrated higher endothelial volume and luminal volume in the lesional psoriatic skin compared to uninvolved skin of patients with psoriasis as well as control subjects . the authors suggested that increase in these parameters was partly due to the increase in number of vascular profiles . in another study , computerized image analysis was performed to demonstrate the great degree of expansion of the vascular plexus in papillary dermis . the same study also showed significant endothelial proliferation in the papillary dermis of active psoriatic plaques . this study aimed at evaluating the vascular changes in psoriasis vis -  - vis psoriasiform dermatitis . this comparison has not been performed in the available literature till date , to the best of our knowledge . we found a significantly higher length density of vessels in psoriasis compared to psoriasiform lesions ( p<0.05 ) . microvessel density was also higher in psoriasis , though the difference did not reach statistical significance . these results indicate that though there is some vascular proliferation in response to inflammation in psoriasiform dermatitis , the tortuosity , and elongation of vessels reflected by length density is significant in psoriatic lesions only . with the advancing automation in diagnosis , these morphometric techniques might assist in differentiation between psoriasis and psoriasiform lesions , especially in early lesions of psoriasis . the vascular proliferation in psoriatic skin systemic therapy for psoriasis , such as methotrexate , cyclosporine , and tnf antagonists exert their therapeutic effect by immune modulation as well as interference with proangiogenic mediators . in addition , several molecules such as neovastat ( inhibitor of endothelial cell proliferation ) and inhibitors of vegf receptors are undergoing clinical trials . hern et al . , performed native capillaroscopy and showed a significant reduction in the microvessel density , image area fraction , length , density and vessel image width after pulsed dye laser treatment of plaque psoriasis . hence , the superficial microvascular bed in psoriatic skin is a legitimate and easily accessible target for antiangiogenic therapy . the present study demonstrates significant difference in the papillary dermal vasculature between psoriatic skin and psoriasiform dermatitis . these results , which need to be confirmed in further larger studies ,
background : vascular proliferation in the papillary dermis is considered to be an important and probably an early feature of psoriasis . 
 few morphometric studies have attempted to analyze the vascular changes . 
 however , no study was found in the available literature comparing vascular changes between psoriasis and psoriasiform dermatitis.materials and methods : skin biopsies from 25 cases each of psoriasis and psoriasiform lesions were immunohistochemically stained for cd34 ( endothelial marker ) . 
 microvessel density ( mvd ) , microvessel length density and ratio of microvessel area to papillary dermal area were calculated using image analysis software.results:skin biopsies from psoriasis showed higher staining for cd34 on light microscopy . using morphometric techniques , 
 microvessel length density was significantly higher in psoriasis compared to psoriasiform lesions ( p value < 0.05 ) . 
 mvd was also higher in psoriasis , though the difference was not significant . 
 the ratio of microvessel area to dermal area was almost similar in both the groups.conclusion:our results indicate that vascular tortuousity and dilatation is significant only in psoriatic lesions . 
 these results may assist in automated diagnosis of skin biopsies .