Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that is clinically defined by lesions ranging from painful, deep seated nodules to abscesses, draining sinus tracts, and ultimately, irreversible fibrotic scars. While the etiology remains unclear, a number of mechanisms ranging from genetics to aberrations of the immune system have been proposed. In addition, HS has a number of associations and may occur in conjunction with several diseases that span a host of medical specialties. The estimated prevalence ranges are from 1% to 4%; however, a large degree of under-reporting and misdiagnosis of this condition likely underestimates its true clinical significance. The debilitating consequences of missed diagnoses or improper management leads to severe pain and irreversible cutaneous manifestations (i.e., fistulae, sinus tracts, disfiguring scarring). HS has been found to significantly impair patients' quality of life to a greater degree when compared with other skin conditions. Early recognition and treatment are critical for a favorable prognosis, and diagnostic delays may be related to variable presentations within numerous comorbidities. Here we provide an in-depth, clinical-based review of HS, highlighting the clinical presentation, pathophysiology, grading systems, epidemiology, and comorbidities, in hopes of shedding light on an often misunderstood disease and ultimately moving closer to a more conclusive understanding of its various presentations and association.

Nail manifestations are 1 of the several extrapulmonary findings associated with COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nail changes, however, have been largely ignored and not yet summarized. This article is intended to increase awareness of nail manifestations of SARS-CoV-2, which occur weeks to months after acute infection and the periungual pernio-like changes may occur concomitantly with infection. An electronic search was carried out in PubMed (Medline), Science Direct, and Scopus databases. The following keywords and all of their possible combinations were used to identify studies: “SARS-CoV-2,” “COVID-19,” “Coronavirus,” “2019-ncov,” “nail,” and “nails.” Six case reports were included in this study. Manifestations identified included red half-moon sign, transverse orange nail lesions, Mees’ lines, and Beau’s lines. Though largely nonspecific, these findings can be recognized with the onset of symptom onset or as late as 16 weeks following the disease. Some of these findings are shared with other conditions associated with a proinflammatory state. Nail changes offer unique insight into the pathophysiologic basis for SARS-CoV-2 and they may serve as diagnostic clues.

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