Histopathologic differentiation of nevus cell aggregates and metastatic melanoma in lymph nodes is challenging. Patients with melanoma who had undergone sentinel lymph node (SLN) biopsy were evaluated using univariate and multivariate analyses as well as Kaplan-Meier statistics. Of the 651 patients, 50 (7.7%) had a nodal nevus in the SLN. In the logistic regression model, primary melanoma on the lower extremities proved to be the strongest independent negative predictor of nodal nevi with an odds ratio of 0.11 (95% confidence interval, 0.034-0.36; P = .0002). Overall 5-year survival (P = .17) and 5-year disease-free survival (P = .45) of patients with nodal nevi did not significantly differ from that of patients with negative SLNs. The frequency and anatomic localization of nodal nevi observed in the present study are in line with previous studies. Our 5-year survival data clearly demonstrate that nevus cell aggregates in lymph nodes have to be considered a benign condition even though it occurs in patients with melanoma. This study provides an indirect proof of validity and accuracy of current histopathologic methods for differentiation between nodal nevi and melanoma metastasis.

IMPORTANCE The variation in both clinical appearance and responses to diverse treatment options emphasize the importance of an accurate, clinically relevant, yet easy-to-use scoring system in hidradenitis suppurativa. OBJECTIVE To propose and provide validation data for the newly designed Severity Assessment of Hidradenitis Suppurativa score. DESIGN, SETTING, AND PARTICIPANTS We prospectively assessed disease severity using Hurley staging and the modified Hidradenitis Suppurativa Score in 355 patients referred to Ruhr-University Bochum Department of Dermatology between March 2016 and June 2017. We also assessed disease severity via the Severity Assessment of Hidradenitis Suppurativa score. MAIN OUTCOMES AND MEASURES Evaluation and assessment of convergent validity and responsiveness to treatment of the Severity Assessment of Hidradenitis Suppurativa score. RESULTS Eighty-eight of the 355 patients (134 [37.7%] men and 221 [62.3%] women with a median [IQR] age of 40 [30-49] years) were classified as Hurley stage I, 221 were Hurley stage II, and 46 were Hurley stage III, with an overall median modified Hidradenitis Suppurativa Score of 31 (interquartile range [IQR], 19.3-53). The median total Severity Assessment of Hidradenitis Suppurativa score was 6 (IQR, 4-9), significantly different among the 3 Hurley groups. The median SAHS score for patients in Hurley stage I was 5 (IQR, 3-6), 6 (IQR, 5-9) for patients in Hurley stage II, and 9 (IQR, 7-12) for patients in Hurley stage III (P < .001, Kruskal-Wallis test). Correlation analysis showed a significant correlation between the modified Hidradenitis Suppurativa Score and the Severity Assessment of Hidradenitis Suppurativa score (r = 0.79, P < .001). Disease severity assessment before and after 3 months of conservative systemic treatment showed a significant correlation between the Severity Assessment of Hidradenitis Suppurativa score and modified Hidradenitis Suppurativa Score. Both the mHSS (P = .001) and the SAHS score (P < .001) significantly differed between the baseline visit (median mHSS, 33 [IQR, 24-52]; median SAHS score, 6 [IQR, 5-9]) and the 3-month visit (median mHSS, 28 [IQR, 15-43.5]; median SAHS score, 5 [IQR, 4-6.3]). The 2 patient-reported items demonstrated excellent test-retest reliability with intraclass correlation coefficient values greater than 0.8. CONCLUSIONS AND RELEVANCE Our validation data demonstrated that the Severity Assessment of Hidradenitis Suppurativa score is a disease severity instrument that significantly correlates with Hurley staging and the modified Hidradenitis Suppurativa Score, and is responsive enough to measure treatment outcome.

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Dear Editor, Growing evidence suggests that SARS‐CoV‐2 vaccination is associated with a variety of cutaneous reactions, also including autoimmune‐mediated conditions such as autoimmune blistering diseases such as bullous pemphigoid (BP). 1,2 We report new‐onset BP in two patients following the first SARS‐CoV‐2 vaccination.