The Application Of Dermoscopy In The Differential Diagnosis Of Plaque Psoriasis And Pityriasis Rubra Pilaris

BackgroundDermoscopy is a kind of microscopic image analysis technology,can increase the permeability of the skin,and reduce the reflected light through a special transmitter.Dermoscopy is a non-invasive examination method,and duing to the function of amplification,it can make many morphological characteristics visible which are invisible to the naked eye.Mainly by the use of oil,light and optical amplification device.Through the epidermal layer showing the lower epidermis,dermal-epidermal junction,papillary dermis and superficial dermis,it can oberserve what can not be observed by the naked eye,such as the vascular morphology in the dermal layer,vascular distribution and arrangement,and even the pigment structure.The manifestations of dermoscopy have certain reliance corresponding between clinical and pathological manifestations.In the other words,dermoscopy could be taken as a bridge between the clinical dermatology and dermatopathology.It represents a link between macroscopic clinical skin pathology and microscopic skin histopathological performance.Dermoscopy,first being used in the diagnosis and differential diagnosis of pigmented diseases,has received the affirmation of its diganostic value in the pigmented neoplasm both in the domestic and abroad academia.Recently,dermoscopy has also began to be applied in the field of non pigmented skin diseases.A large number of literature shows that,in clinical examination increase dermoscopy greatly improving the diagnosis accuracy,thereby reducing the number of biopsy,which reduces the medical expense and unnecessary surgical morbidity.In addition,this procedure will not only establish the clinical confidence of doctors,but also establish the patient's confidence.Pityriasis rubra pilaris(PRP)is a rare chronic squamous keratotic inflammatory dermatosis characterized by flaky erythema scaly,follicular keratosis,and palmplantar hyperkeratosis.The etiology and pathogenesis of PRP are unclear.There are six different subtypes in children and adults.Though controversial about the classification of PRP still exists,it is always being devided into two types,familial(hereditary,congential)type and acquired type.The former is scare,and can always being found in childhood,while the latter is common in adulthood.In mild type,the skin rashes can extended to the extermities,while the serious case can have much generalized manifestation,sometimes even evolved into the diffuse erythroderma.Psoriasis is a chronic inflammatory dermatosis with erythema and scale.As a multiple genetic deficiency disease,psoriasis could be induced by various factors,such as trauma,infection,drug,etc.With low onset-age,high incidence,long duration,and susceptible to various inducible factors,the disease can relapse again and again,not only affect the physical health of patients,but also affect their psychological condition,so as to do harm to their living quality.Therefore,the diagnosis and treatment of psoriasis is an important research area for dermatologists,which is of great significance to the improvement of the quality of the psoriasis patients' life.PRP and plaque psoriasis(PP)all belong to erythema squamous inflammatory dermatosis,mostly with typical clinical characteristics can contribute to the clinical diagnosis,but for the atypical cases,sometimes histopathological examination should be performed to make clear diagnosis.Researchers have found that most lesions with erythematous dermatosis,having changes in pigment and vascular structure mainly in the epidermis and dermis.The dermoscopy of PP has been widely studied both at home and abroad,and the characteristics of skin microscopy PRP are less studied in foreign countries,and there is also no report in China.ObjectiveTo study the dermoscopic patterns of Pityriasis rubra pilaris and Plaque psoriasis,assess the value of dermoscopy in the differential diagnosis of both diseases.Methods1.Data from March 2016 to November 2017 in the first affiliated hospital of zhengzhou university dermatologist outpatient clinic and pityriasis rubra pilaris and plaque psoriasis cases,a total of 42 cases.It consisits of PRP 15 cases,PP 27 cases.There were 8 males and 7 females in PRP group.Age 3 ~ 55 years old,median age 42.6 years old;The course of illness was 0.5 ~ 2 years,with an average of 1.1 years.15 males and 12 females in PP group;Age 7 ~ 53 years old,median age 44.3 years old;The course of illness was 0.5 ~ 2.1 years,with an average of 1.2 years.2.Dermoscopy was performed on all cases of the recently developed skin lesions of trunk and limbs,using portable demoscopy German company FotoFinder dermoscopy system(Medicam 800 hd FotoFinder Systems GmbH,Birbach,Germany),with the Handyscope iPhone6 s software to connect to the mobile phone,output dermoscopy images,skin assessment of background color,white keratin plugs,Vascular distribution,vascular morphology,color of scales,Scales distribution.3.A biopsy was performed on all cases of the recently developed skin lesions of trunk and limbs,and after the specimens were taken,hematoxylin-eosin staining was used for staining,which was observed under the microscope of philiphs.4.The statistical description method of experimental data of the classification data using the percentage.To determine whether there was a statistical difference between the dermoscopic characteristics of the two diseases by using the chi 2 test,if it does not meet the chi square test conditions,using the Fisher exact test probability method,P < 0.05 for the difference was statistically significant.All statistics were analyzed by SPSS 22.0 statistical software.Results1.The clinical manifestations of PRP group were mainly flaky erythema scale,follicular keratosis papule and palmoplantar hyperkeratosis,and the main clinical manifestations of PP group were erythema scale,membrane phenomenon,and point hemorrhage.2.Dermoscopic results showed yellowish background(86.7%),whitish keratotic plugs(73.3%),linear vessels(86.7%)and vessel distributing at the edge(53.3%)in PRP group,and bright red background(85.2%),white diffuse scales(74.1%),dotted vessels(96.3%),and diffused distributing vessel(81.5%)in PP group,showing significant differences between two group(P<0.05).3.The histopaththologic results showed follicular keratotic plugging(46.7%),vertical and horizontal hyperkeratosis and parakeratosis(73.3%),hypergranulosis(80.0%),and irregular spinous hypertrophy(86.7%)in PRP group,and fusion parakeratosis(88.9%),decreased or disappeared granule(85.2%),regular spinous hypertrophy(81.5%),epidermal keratinization of Munro microabscess(48.1%)in PP group,showing significant differences between two group(P<0.05).ConclusionPRP and PP have the dermoscopic and histopathologic features of its own,dermoscopy is of great value in the differential diagnosis.