There have been increasing reports of skin manifestations in COVID-19 patients. We conducted a systematic review and included manuscripts describing patients with positive RT-PCR coronavirus testing from nasopharyngeal swabs who also developed cutaneous manifestations. A total of 655 patients were selected, with different types of skin rashes: Erythematous maculopapular (n = 250), vascular (n = 146), vesicular (n = 99), urticarial (n = 98), erythema multiforme/generalized pustular figurate erythema/Stevens-Johnson syndrome (n = 22), ocular/periocular (n = 14), polymorphic pattern (n = 9), generalized pruritus (n = 8), Kawasaki disease (n = 5), atypical erythema nodosum (n = 3), and atypical Sweet syndrome (n = 1). Chilblain-like lesions were more frequent in the younger population and were linked to a milder disease course, while fixed livedo racemosa and retiform purpura appeared in older patients and seemed to predict a more severe prognosis. For vesicular rashes, PCR determined the presence of herpesviruses in the vesicle fluid, which raised the possibility of herpesvirus co-infections. The erythema-multiforme-like pattern, generalized pustular figurate erythema and Stevens-Johnson syndrome were most frequently linked to hydroxychloroquine intake. A positive PCR determination of SARS-COV-2 from conjunctival swabs suggest that eye discharge can also be contagious. These cutaneous manifestations may aid in identifying otherwise asymptomatic COVID-19 carriers in some cases or predict a more severe evolution in others.

Background: Plaque psoriasis (PP) and seborrheic dermatitis (SD) are chronic inflammatory skin diseases with similar clinical and pathological features. Differential diagnosis can be difficult, especially when particular skin areas of the face are involved. Reflectance confocal microscopy (RCM) has been demonstrated to be useful for ‘real-time' diagnosis of skin inflammatory diseases. Objective: To define distinctive confocal criteria of SD and to evaluate the usefulness of this technique for noninvasive differential diagnosis with PP. Methods: A total of 40 patients affected by PP and 19 patients by SD involving the face were recruited and subjected to RCM evaluation. Univariate and adjusted odds ratios were calculated. Discriminant functions were used to plot ROC curves. Results: The results disclosed specific patterns for SD and PP. The following distinctive confocal features for SD have been identified: spongiosis, dermal inflammation and horizontal orientation of dilated blood vessels. Conclusion: SD has a specific and easily recognizable confocal pattern supporting clinical differentiation with PP.

The prompt identification of cutaneous lymphoproliferative disorders (CLD) has always been a challenge in dermatological practice, due to the rarity of this group of diseases, the heterogeneity in clinical presentation, and plenty of variants described in the literature so far. The strict cooperation between dermatologist and pathologist is the key element for the correct diagnosis of CLD deriving from the perfect integration of clinical and histopathological features. In this complex context, dermoscopy could play an adjuvant role in the achievement of the diagnosis, as it fits itself as the third diagnostic tool in the paraphernalia of the dermatologist between the clinical and histopathological examination. This review provides the state of art of dermoscopy of CLD.

Introduction: The use of reflectance confocal microscopy (RCM) for imaging the skin non-invasively has risen constantly during the last decade. One of the main fields of application is in skin cancer diagnosis and, in particular, melanoma diagnosis. Nowadays, RCM is regarded as a secondary level imaging tool, after clinical and dermoscopic examination. Several studies have investigated the diagnostic accuracy of RCM as compared to dermoscopic examination, and its value in enhancing early diagnosis of dermoscopic difficult melanomas. Its axial resolution and its non-invasive and easy clinical application represent the key features for the diffusion of this technique. Areas covered: The purpose of this paper was to review the principles behind RCM image acquisition as well as to describe and discuss key RCM features of melanoma. Moreover, we conducted a literature search in order to highlight the current available evidence about RCM sensitivity and specificity in the diagnosis of melanoma. Expert opinion: During the last decade, we have witnessed an increased interest in noninvasive imaging tools for the diagnosis of skin cancer. RCM is one of the most studied of a series of diagnostic methods emerging in the field of melanoma imaging. RCM is nowadays a well-established technique, integrated in the diagnostic armamentarium of the dermatologist in many referral centres. Most probably in the future, RCM will be more and more frequently available in tertiary referral centres, thus the knowledge of the pros and cons of the tool and its clinical applicability is of upmost importance in order to allow correct referrals with the final aim of improving diagnostic accuracy.

We present two patients with stage IV melanoma, the first with BRAF wild-type melanoma with multiple visceral metastases treated with immunotherapy (pembrolizumab) and the second with BRAFV600E melanoma with subcutaneous and lymph nodes metastasis treated with BRAF and MEK-inhibitors (dabrafenib/trametinib). Already after the second cycle of immunotherapy, the first patient developed a diffuse regression of nevi, perceptible only with the use of dermoscopy and 3 months later a clinically evident poliosis of the eyebrows. The second patient, treated with dabrafenib/trametinib, developed small areas of leukoderma on his chest and white halos around nevi with a dermoscopic globular or structureless pattern. Both observations are suggestive for an immune reaction against melanocytic cells, which is further supported by the complete response to systemic therapy in both patients. It has been demonstrated that the development of vitiligo-like depigmentation during immunotherapy is associated with a better prognosis; in our patient, the phenomenon of poliosis appeared much later than the dermoscopic presence of regression among his nevi, suggesting that the latter may be an early sign (along with vitiligo-like phenomena) of good response to immunotherapy. On the other hand, the development of halo nevi and leukoderma during treatment with BRAF/MEK-inhibitors, suggests that not only immunotherapy but also targeted therapy may induce an immunologic response against melanoma and nevi, again indicative of a favorable prognosis. More data are needed to confirm these findings; however, they indicate that dermatologists should be involved in the follow-up of patients with melanoma, both in studies and clinical practice.