Diagnostic spectrum and therapeutic efficiency in teledermatology–Results of the largest cohort study to date

Timely and comprehensive dermatological care is a major challenge. Digitized medical consultation offers a possibility to overcome this problem. Here, we studied the diagnostic spectrum and treatment success in teledermatology in the largest cohort to date. Over 12 months, 21 725 individuals received a diagnosis and therapeutic advice using the asynchronous image‐text method. In the context of quality management, 1802 individuals (~10%) of both sexes with a mean age of 33.7 years (SD 15.36) received a follow‐up 3 months after the initial consultation to assess the treatment outcome. Of these, 81.2% did not require a face‐to‐face consultation. Therapeutic efficiency could be ascertained in 83.3% of the patients, whereas 10.9% did not improve, and 5.8% did not provide an information on the course of therapy. Teledermatology is a useful tool in digitalized medicine and complements the classical in‐person dermatological examination, as shown by the high degree of treatment efficacy in this study. Although face‐to‐face consultations can not and should not be completely substituted by teledermatology it reflects a significant contribution to patient care and justifies the further expansion of digital structures in dermatological care.

Over 12 months, 21 725 individuals received a diagnosis and therapeutic advice using the asynchronous image-text method. In the context of quality management, 1802 individuals (~10%) of both sexes with a mean age of 33.7 years (SD 15.36) received a follow-up 3 months after the initial consultation to assess the treatment outcome. Of these, 81.2% did not require a face-to-face consultation. Therapeutic efficiency could be ascertained in 83.3% of the patients, whereas 10.9% did not improve, and 5.8% did not provide an information on the course of therapy. Teledermatology is a useful tool in digitalized medicine and complements the classical in-person dermatological examination, as shown by the high degree of treatment efficacy in this study. Although face-to-face consultations can not and should not be completely substituted by teledermatology it reflects a significant contribution to patient care and justifies the further expansion of digital structures in dermatological care.

K E Y W O R D S
diagnostic spectrum, teledermatology, telemedicine, therapeutic efficiency advice within 24 h via a certified teledermatology app provider (Dermanostic, inc.; https://derma nostic.com). The teledermatological consultation could be requested either by downloading an app from the Google Play Store/Apple App Store or by using the WebApp directly in the browser (no download necessary). Based on a standardized protocol and the SAF method, each patient submitted three clinical pictures and answered a short questionnaire (Table 1). In ambiguous instances, the app provider free of charge offered the further evaluation of such inconclusive cases by an expert panel consisting of three board-certified dermatologists with at least 30 years of professional experience. 5 For quality management, the app provider also continuously conducted a random follow-up of 10% of the patients, which was performed over the phone by trained study nurses using a standardized questionnaire ( Table 2). All individuals in this study provided

| DISCUSS ION
Demographic data regarding gender and age of patients seeking teledermatological advice are scarce, and only a few previous publications have delineated these aspects. 3,4 We could not detect a specific sex predominance in this study, which is in line with the data of previous investigations. 3,4,6 In our cohort, the mean age of the majority of the patients was 33.7 years. This is in accordance with the results of other groups who evaluated the age distribution of patients with varied skin disorders seeking teledermatological advice. 4,6 The most common diagnosis in this study was acne, both in the overall cohort and in the follow-up cohort. These results are consistent with those of traditional office-based FTF outpatient dermatological care. 7 Interestingly though, a recently published TA B L E 1 Questionnaire for teledermatological consultation.  results of other groups who reported a diagnostic accuracy in the range of 70%-85%. 11,12 To the best of our knowledge, the efficiency of a therapeutic regimen prescribed following a teledermatological consultation has not been systematically assessed to date. However, this aspect certainly is one of the major factors underlying patient satisfaction with teledermatology services. 11 Therefore, it might be worth paying more attention to this issue in the future.
In the current study, 81.2% of the individuals who sought a teledermatological consultation did not require an additional FTF examination, in spite of the fact that each patient was encouraged to see a dermatologist in person if symptoms persisted or worsened.
This is in line with previous reports or even better than the results of other groups and suggests a high level of patient satisfaction with the dermatological services provided, in particular the unique feature of a second opinion by an expert panel of highly experienced board-certified dermatologists that was provided in ambiguous and difficult cases. 10,11 Here, 326 individuals (18.3%) were deliberately referred for an additional FTF dermatological examination. As in previous studies by other groups, 92 of these individuals (28.2%) were patients with a suspected diagnosis of a skin tumor who required further diagnostic work-up. 13 Taken together, we report on the largest telederamtological follow-up study on varied dermatological diseases in the context of quality assessment. Our results show that teledermatology is a valuable digital complement to the traditional dermatological FTF examination that is easily accessible for the patient at any time and associated with a high degree of therapeutic efficiency.

ACK N OWLED G M ENT
Open Access funding enabled and organized by Projekt DEAL.