Through basic science as well as animal and human clinical trials, the evidence is growing for the use of probiotics in the treatment of acne. Acne formation is dependent upon several processes, including follicular hyperkeratinization, excess sebum production, Propionibacterium acnes colonization and an inflammatory cascade. The antimicrobial properties of probiotics as well as the modification of the skin microbiome may decrease levels of P. acnes on the skin. Additionally, successful acne outcomes are influenced by compliance with topical regimens, which can commonly cause skin barrier disruption, leading to dryness and irritation. Consequently, calming inflammation as well as maintaining skin hydration and barrier repair is of primary importance when treating acne. In this chapter, we discuss how probiotics affect several factors in the pathophysiology of acne development and can improve the treatment outcomes.

Medallion-like dermal dendrocyte hamartoma is a rare congenital lesion that is more commonly seen in females. It often presents at birth on the neck or upper trunk as a well-circumscribed, atrophic patch with wrinkling of the overlying skin. Clinically, the differential diagnosis includes atrophoderma, anetoderma, and congenital atrophic dermatofibrosarcoma protuberans. Histologic findings show epidermal atrophy and dermal spindle cell proliferation that is CD34 positive, along with Factor XIIIa in the original reports. Due to this CD34 positivity, another name for the lesion is plaque-like CD34+ dermal fibroma. We present a unique patient case as he is male and the lesion is located on his abdomen. Further reports and studies need to be done for thorough understanding of this neoplasm. K E Y W O R D S CD34, Factor XIIIa, medallion-like dermal dendrocyte hamartoma, plaque-like CD34+ dermal fibroma 1 | INTRODUCTION Medallion-like dermal dendrocyte hamartoma (MLDDH) is a rare cutaneous lesion that has also been described as plaque-like CD34+ dermal fibroma. This entity was first described in 2004 by Rodriguez-Jurado et al with three female patients presenting with atrophic, circumscribed patches that were present since birth on the neck and upper chest. 1 Including our patient, there are 23 reports of this fascinating lesion, leaving much still to be understood. 1-14 Many cases are described in females and present at birth or young age, thought to be congenital. These neoplasms are more commonly reported on the neck and upper trunk. Histologic exam shows epidermal atrophy and spindle cell proliferation in the dermis that staining with CD34 andFactor XIIIa have determined the cells to be dermal dendrocytes. Dermal dendrocytes are believed to be a part of the skin's immunologic response system and associated with collagen tissue. 15 Factor XIIIa+ dermal dendrocytes are considered dermal macrophages, 16 while CD34 expression defines undifferentiated mesenchymal cells whose exact role is undefined. 17 Both of these cell types are often located around adnexal structures in the dermis. 17 The importance of pathology is to exclude the differential diagnosis of dermatofibrosarcoma protuberans (DFSP), often using molecular studies. We describe a patient presentation that contravenes the classic description, in order to bring awareness of this interesting neoplasm with hopes of further understanding. | CASE REPORTA 25 year old Caucasian male presented to the dermatology clinic for a routine skin examination. The patient had no lesions of concern. His dermatologic history involved one moderately dysplastic nevus on his left lower abdomen that had been previously excised. No other significant medical history was noted. On exam, a yellow-to brown, well-circumscribed atrophic patch with slight erythema and visible blood vessels was located on his right lower abdomen (Figure 1). The patient stated that the lesion had been present since a young age and it had remained asymptomatic.The patch was submitted to a skin biopsy. A clinic...

Dermatologic manifestations associated with coronavirus disease 2019 (COVID-19) remain broad and nonspecific. While a surge of “COVID toes” have been reported worldwide, very few cases have been documented in reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed COVID-19 patients. Furthermore, majority of confirmed COVID-19 patients with chilblains-like lesions presented with cutaneous lesions localized to the toes, which was preceded by other systemic symptoms. Our case report describes an occurrence of chilblains-like lesions, limited to the fingers, in an asymptomatic COVID-19 patient confirmed by RT-PCR.