Features And Differentiation Of Reflectance Confocal Microscopy And Dermoscopy In Scalp Seborrheic Dermatitis And Scalp Psoriasis

Objective:Seborrheic dermatitis,psoriasis are easy to occur in the scalp and other places,which are characterized by scaly erythema,in only the scalp involvement.It is difficult to distinguish between the two diseases.Inrecent years,reflectance confocal microscopy(RCM)and dermoscopy are more and more used in the diagnosis of inflammatory dermatosis,but seborrheic dermatitis mainly studies facial lesions,while psoriasis mainly focuses on trunk and limb plaque type,there are few studies on scalp seborrheic dermatitis and psoriasis.The purpose of this study was to summarize the characteristics of RCM and dermascopy in scalp seborrheic dermatitis and scalp psoriasis,and to evaluate the application value of RCM and dermoscopy in distinguishing scalp seborrheic dermatitis from scalp psoriasis.Methods:30 patients with seborrheic dermatitis and 30 patients with psoriasis scalp were included in this study,all of them were examined by RCM,dermoscopy,and some of them were examined by histopathology,the frequency of RCM and dermoscopic characteristics were summarized,and the sensitivity and specificity for the diagnosis and distinguish of the two diseases.Results:The main features of RCM in scalp seborrheic dermatitis were as follo-ws:parakeratosis,spongiosis,horizontal dilatied blood vessels,dermal inflammatory cell infiltration and follicular keratotic plugging.Spongiosis(sensitivity 100%,specifi-city 83.3%)and horizontal dilatied blood vessels(sensitivity 90%,specificity 86.7%)had higher sensitivity and specificity for diagnosis.The main dermoscopy characteris-tics of the disease were:yellow-red background,branching vessels,atypical vessels,focal distribution of vessels,yellow scales,featureless areas and honeycomb pigment.Honeycomb pigment(sensitivity 90%,specificity 100%),branched vessels(sensitivity 90%,specificity 90%)and featureless areas(sensitivity 86.7%,specificity 93.3%)had higher sensitivity and specificity for diagnosis.The main features of RCM in scalp psoriasis were as follows:hyperkeratosis,parakeratosis,Munro microabscess,up migrated dermalpap illae,enlarged dermal papillae,dermal inflammatory cell infiltration.The up-migrated dermal papillae(sensitivity 93.3%,specificity 100%)and enlarged dermal papillae(sensitivity 93.3%,specificity 80%)had high sensitivity and specificity in the diagnosis of scalp psoriasis..The main dermoscopy characteristics of the disease were:bright-red background,punctate vessels,glomerular vessels,hairpin vessels,annular vessels,uniform distribution of vessels,white scales.Annular vessels(sensitivity 83.3%,specificity 100%)and hairpin vessels(sensitivity 80%,specificity 100%)were highly sensitive and specificity in the diagnosis of scalp psoriasis.Scalp seborrheic dermatitis and scalp psoriasis differentiation:spongiosis,horizontal dilatied blood vessels with the up-migrated dermal papillae,enlarged dermal papillae are the main points of identification in RCM.Honeycombpigment,branchedvessels featureless areas with Annular vessels,hairpin vessels are the main points of identification in dermoscopy.Conclusion:Scalp seborrheic dermatitis and scalp psoriasis has relatively unique characteristics of RCM and dermoscopy.RCM and dermoscopy are of great value in differentiating scalp seborrheic dermatitis from scalp psoriasis.