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Dogs are susceptible to a diverse spectrum of dermatologic conditions, several of these skin disorders are analogous to dermatologic conditions occurring in humans. Pool toes appears on the plantar surface of the feet and toes; it is an aquatic pool-associated frictional dermatosis that results from repeated rubbing of the feet and toes against the rough cement at the bottom of the pool or its border. A frictional dermatosis that can develop on the uncalloused paw pads of puppies, resulting from repeated rubbing of the paws against ambient temperature, not heated, paved road is pavement paws. Neither pool toes nor pavement paws result from contact with a hot surface; these dermatoses are distinctive from beach feet, a thermal-associated superficial burn to the skin resulting from the hot temperature of the sand that contacts that the plantar feet and toes. In conclusion, similar to pool toes, the pathogenesis of pavement paws is a frictional dermatosis that can develop on the uncallused paw pads of puppies resulting from repeated rubbing of the paws against ambient temperature, not heated, pavement.

A simple and rapid method that is not based on race and ethnicity for classifying people with skin of color is of paramount importance in dermatology. The currently used Fitzpatrick classification of sun-reactive skin types is inadequate. Newer scales that have been used in immigration surveys and sociology studies are not applicable in the office setting. A new, non-racial and non-ethnic, colorimetric scale for skin of color has recently been proposed that is simple to perform. The scale has five colors: very light beige (skin color type 1), light brown (skin color type 2), medium brown (skin color type 3), dark brown (skin color type 4) and very dark brown (skin color type 5); an individual with white skin, such as in albinism, would have a skin color type 0 in this classification. In conclusion, the colorimetric scale enables the rapid classification of individuals with skin of color and allows for accurate assessment of skin cancer risk, more appropriate management of cosmetic dermatologic procedures and aesthetic devices, and enhanced ability for focused counseling regarding hair products, skin care interventions, and color-targeted makeup based on the person's skin tone.

Herpetic geometric glossitis is a unique morphologic variant of HSV (herpes simplex virus) type 1 infection on the dorsum of the tongue that presents as an extremely painful linear central lingual fissure with a branched pattern. in the center of the tongue; there is a branched pattern of fissures that extend bilaterally from the central linear fissure. Herpetic geometric glossitis has been reported in 11 patients; 8 of these individuals were immunocompromised. Medical conditions and immunosuppressive medication treatment (7 patients) or only medical disorders (3 patients) or neither (1 patient) were present. HSV type 1 infection was diagnosed by viral culture in (7 patients), Tzanck preparation (2 patients) or clinically (2 patients). Mucocutaneous HSV infection at non-lingual locations--including the lips, labial mucosa, face and chest--were observed in 5 patients. All patients' symptoms and lesions responded to treatment with oral antiviral therapy: acyclovir (9 patients), famciclovir (1 patient) or valacyclovir (1 patient). The lingual pain and dorsal tongue fissures completely resolved completely within two to 14 days. In summary, herpetic geometric glossitis is a unique HSV type 1 infection, usually in immunocompromised patients, that occurs on the dorsal tongue and responds completely after treatment with orally administered antiviral therapy.

The knife-cut sign is a distinctive manifestation of herpes simplex virus (HSV) type 1 or HSV type 2 infection that has been described in at least 10 immunocompromised patients. It appears as an extremely painful linear erosion or fissure in an intertriginous area such as the body folds beneath the breast, or within the abdomen, or in the inguinal region. Also, concurrent HSV infection at other mucocutaneous sites, or viscera, or both have been observed. The patients had medical conditions (at least 9 patients) and/or immunosuppressive drug therapy (6 patients). The diagnosis of HSV infection was confirmed by viral culture (8 patients), biopsy (4 patients), direct fluorescence antibody testing (3 patients), immunohistochemistry staining (2 patients), polymerase chain reaction (2 patients), or Western blot serologic assay (1 patient). Knife-cut sign-associated HSV infection is potentially fatal; three patients died. However, clinical improvement or complete healing occurred in the patients who received oral valacyclovir (1 patient), or intravenous acyclovir (2 patients), or intravenous acyclovir followed by foscarnet (1 patient). In summary, HSV infection associated with a positive the knife-cut sign is a potentially fatal variant of HSV infection that occurs in the intertriginous areas of immunocompromised patients and usually requires intravenous antiviral therapy.

Cutaneous basal cell carcinoma in situ is a recently proposed subtype of this skin cancer. It is characterized by either restriction of the tumor cells within the epidermis or the presence of tumor cells contiguous with the overlying epidermis that extend into the underlying dermis, or both. Importantly, cancer invasion-demonstrated by non-contiguous aggregates of basaloid tumor cells in the dermis-is not a feature of in situ basal cell carcinoma of the skin. A 63-year-old woman with cutaneous basal cell carcinoma in situ-superficial type that presented as an erythematous scaly plaque on her abdomen and a 61-year-old man with a cutaneous basal cell carcinoma in situ-fibroepithelioma type that presented as a flesh-colored smooth exophytic nodule on his back are reported. The characteristics of in situ basal cell carcinoma of the skin in these individuals are summarized. In conclusion, similar to other cutaneous malignant neoplasms-such as squamous cell carcinoma, malignant melanoma, and Merkel cell carcinoma-basal cell carcinoma of the skin can also present as an in situ cancer.

Patients with Muir-Torre syndrome may have a systemic malignancy and a sebaceous neoplasm such as an adenoma, epithelioma, and/or carcinoma. The syndrome usually results from a germline mutation in one or more mismatch repair genes. Iatrogenic or acquired immunosuppression can promote the appearance of sebaceous tumors, either as an isolated event or as a feature of Muir-Torre syndrome and may unmask individuals genetically predisposed to the syndrome. Two iatrogenically immunosuppressed men with Muir-Torre syndrome features are described. Similar to these immunocompromised men, Muir-Torre syndrome-associated sebaceous neoplasms have occurred in solid organ transplant recipients, human immunodeficiency virus-infected individuals, and patients with chronic diseases who are treated with immunosuppressive agents. Muir-Torre syndrome-associated sebaceous neoplasms occur more frequently and earlier in kidney recipients, who are receiving more post-transplant immunosuppressive agents, than in liver recipients. The development of sebaceous neoplasms is decreased by replacing cyclosporine or tacrolimus with sirolimus or everolimus. Specific anti-cancer vaccines or checkpoint blockade immunotherapy may merit exploration for immune-interception of Muir-Torre syndrome-associated sebaceous neoplasms and syndrome-related visceral cancers. We suggest germline testing for genomic aberrations of mismatch repair genes should routinely be performed in all patients-both immunocompetent and immunosuppressed-who develop a Muir-Torre syndrome-associated sebaceous neoplasm.

Perivascular epithelioid cell tumor (PEComa) expresses melanocytic and smooth muscle markers. A man with a primary malignant cutaneous (distal left forearm) PEComa is reported. Immunohistochemistry demonstrated MiTF, HMB-45, caldesmon, desmin, and smooth muscle actin, as well as BCL1, CD10, and CD68. Next generation sequencing showed four pathogenic genomic aberrations involving BIRC3, FANCC, TP53, and TSC1 genes. His work-up was negative for metastatic disease; a wide local excision was performed. Including the reported patient, cutaneous PEComa has been described in 65 individuals: primary benign (N=58), primary malignant (N=5), and metastatic malignant (N=2). Cutaneous PEComa typically presented as a painless, slowly growing nodule of

A collision tumor is a neoplastic lesion comprised of two or more tumors consisting of distinct cell populations in the concurrent location. Multiple skin neoplasms at one site (MUSK IN A NEST) is a term recently coined to describe two or more cutaneous benign or malignant tumors occurring at the same anatomic site. In retrospective studies, seborrheic keratosis and cutaneous amyloidosis have both individually been documented as a component of a MUSK IN A NEST. This report describes a 42-year-old woman who presented with a pruritic skin condition on her arms and legs of 13 years' duration. Skin biopsy results showed epidermal hyperplasia with hyperkeratosis, hyperpigmentation of the basal layer with mild acanthosis, and evidence of amyloid deposition in the papillary dermis. Based on the clinical presentation and pathology findings, a concurrent diagnosis of macular seborrheic keratosis and lichen amyloidosis was established. A MUSK IN A NEST consisting of a macular seborrheic keratosis and lichen amyloidosis is likely a more common occurrence than implied by the paucity of published cases of this phenomenon.

Basal cell carcinoma (BCC) can be a component of a collision tumor in which the skin cancer is present at the same cutaneous site as either a benign tumor or a malignant neoplasm. However, BCC can also concurrently occur at the same skin location as a non-neoplastic cutaneous condition. These include autoimmune diseases (vitiligo), cutaneous disorders (Darier disease), dermal conditions (granuloma faciale), dermal depositions (amyloid, calcinosis cutis, cutaneous focal mucinosis, osteoma cutis, and tattoo), dermatitis, miscellaneous conditions (rhinophyma, sarcoidal reaction, and varicose veins), scars, surgical sites, systemic diseases (sarcoidosis), systemic infections (leischmaniasis, leprosy and lupus vulgaris), and ulcers. The relationship between the BCC and the coexisting non-neoplastic condition may be coincidental or possibly related to the development of the BCC; alternatively, the development of the BCC may be unrelated to the coexisting non-neoplastic conditions and secondary to either a Koebner isomorphic response or a Wolf isotopic response in an immunocompromised district of skin. This paper reviews several of the case reports and studies that describe the association of BCC with these non-neoplastic cutaneous conditions.

Social media (SoMe) refers to a variety of virtual platforms used to enhance sharing of information. To evaluate the influence of SoMe with regards to views and downloads of published dermatology articles, we conducted a retrospective study from July 2020-March 2021 examining articles published on Instagram and Twitter under Dermatology Online Journal (DOJ) accounts and compared these with type-matched and issue-matched articles that were not posted on social media. During this time period, 163 total articles of the three types used for social media (Case Report, Case Presentation, and Photo Vignette) were published in DOJ and 15 were promoted via SoMe. Utilization of SoMe demonstrated a significant (P

Acquired digital fibrokeratoma is a benign fibrous tumor usually located on the toes and fingers. A 63-year-old man with an acquired giant plantar fibrokeratoma is described. He presented with an asymptomatic exophytic nodule of ten years duration; there is no history of trauma to the site. It measured 15x10x5mm and was located on the plantar foot proximal to the third toe. Excisional biopsy established the diagnosis of fibrokeratoma. Giant acquired fibrokeratoma,has been described in 16 patients including ours: three women and 13 men. They are located on either the upper extremity (one man) or the lower extremity (15 individuals). Acquired plantar fibrokeratoma is rare. Including our patient, it has been reported in 11 patients: one woman and ten men. The woman was 13 years of age and the men ranged from 15 to 77-years-old. Plantar acquired fibrokeratomas are located on either the plantar aspect of the toes, the sole of the foot, or the heel. An excisional biopsy provided adequate treatment without subsequent recurrence of both giant and plantar fibrokeratomas.

Hematologic-related malignancy-induced eosinophilic dermatosis (He Remained) has recently been introduced as a new nomenclature to describe the eosinophilic dermatosis that has previously been observed in patients with hematologic malignancies. The condition has been reported in 208 patients; the ratio of men to women is 1.3:1. It is most commonly observed in chronic lymphocytic leukemia patients (77%, 160/208 patients). The chronic and relapsing eosinophilic dermatosis typically presents with pruritic lesions that are pleomorphic in morphology and mimic other conditions. The definitive pathogenesis of He Remained is still being established. However, neoplastic leukemia B cells - directly or indirectly (by stimulating a reactive polyclonal T cell response) - likely have an etiologic role in the pathogenesis of this condition in chronic lymphocytic leukemia patients. In addition, recruitment of eosinophils to the skin may occur secondary to an immune shift toward a T helper 2 type response, possibly caused by the neoplastic cells, that results in these T cells producing interleukin 4. Clinical observations, currently based on the prompt (within four weeks) and sustained (at least 12 weeks to 6 months) resolution of He Remained in two elderly men with He Remained, suggests that dupilumab may be the treatment of choice in chronic lymphocytic leukemia patients with this condition.

Terbinafine is an antifungal agent used in the treatment of hair, nail, and skin dermatophyte infections. Skin side effects to terbinafine are not common. Lichenoid drug eruption is a medication-related adverse cutaneous event; the lesion morphology and pathology mimic lichen planus. A woman with onychomycosis developed a lichenoid drug eruption one week after starting terbinafine. The features of her dermatosis and the characteristics of two additional men who also experienced terbinafine-induced lichenoid drug eruption are discussed. They were receiving a daily terbinafine dosage of either 125mg or 250mg to treat onychomycosis or tinea cruris. The lichenoid drug eruption presented as diffuse or symmetric lesions within one to two weeks after starting terbinafine treatment. The extremities, chest, abdomen, and/or trunk were common sites. Less frequent locations were the lips, nails, palms, soles, and suprapubic region; lesions did not occur on the oral or genital mucosa. The eruption resolved after discontinuation of the medication (with or without treatment using topical corticosteroids, systemic corticosteroids, or both). In addition, more frequently occurring terbinafine-associated cutaneous adverse events (such as urticaria, erythematous eruptions, pruritus, acute generalized exanthematous pustulosis, subacute cutaneous lupus erythematosus, and papulosquamous conditions) are reviewed.

Pleomorphic dermal sarcoma is a cutaneous soft tissue sarcoma that presents as a rapidly enlarging tumor, typically on a sun-exposed location of elderly individuals. The neoplasm shares many similar features — clinical, pathologic, immunohistochemical and genomic — with atypical fibroxanthoma. However, adverse histologic characteristics (deep subcutaneous invasion, tumor necrosis, lymphovascular invasion, and/or perineural invasion) differentiate pleomorphic dermal sarcoma from atypical fibroxanthoma and may account for the more aggressive biologic behavior of pleomorphic dermal sarcoma: local recurrence and metastases. The features of a woman with pleomorphic dermal sarcoma are described. Her sarcoma presented as a rapidly growing ulcerated red nodule on the left side of her face. Imaging studies were performed prior to surgery. The tumor was extirpated with a wide local excision and she received postoperative radiotherapy. There has been no recurrence or metastasis at one-year follow-up. Pleomorphic dermal sarcoma has previously been referred to as a malignant fibrous histiocytoma (until the term became antiquated) and an undifferentiated pleomorphic sarcoma. However, the latter term includes not only neoplasms from the skin but also sarcomas from internal organs, retroperitoneal and osteoid origin. Therefore, when classifying this undifferentiated soft tissue sarcomas of cutaneous origin, the term pleomorphic dermal sarcoma may be preferred.

Localized deposition of mucin in the upper dermis is referred to as cutaneous focal mucinosis. Patients with this condition either present with a single skin lesion (solitary cutaneous focal mucinosis) or numerous skin lesions (multiple cutaneous focal mucinosis). A man with solitary cutaneous focal mucinosis is described and the features of this condition are reviewed. Solitary cutaneous focal mucinosis has a slight male predominance and typically presents in adults, ranging in age from 29 years to 60 years, as a nodule or papule that is flesh-colored or white and most commonly located on an extremity or the trunk. Microscopic examination shows deposition of mucin in the upper dermis; the overlying epidermis can be normal, atrophic or hyperplastic. The skin lesion is often removed at the time of biopsy. However, recurrence has not been observed when the mucin deposition is present at the edge of the biopsy or excision specimen. Although the pathogenesis of this condition remains to be established, in contrast to individuals with multiple cutaneous focal mucinosis, solitary cutaneous focal mucinosis is a unique primary cutaneous mucinosis unrelated to mucinosis-associated systemic diseases.

Nevus sebaceus is a benign skin hamartoma of congenital onset that grows during puberty, and in adulthood can develop secondary benign and malignant neoplasms. The most common benign neoplasms occurring in nevus sebaceus are believed to be syringocystadenoma papilliferum, trichilemmoma, and trichoblastoma. A patient with nevus sebaceus developed not only syringocystadenoma papilliferum but also prurigo nodularis within her hamartomatous lesion; multiple biopsies were necessary to establish the diagnoses. Excision of the residual nevus sebaceus also revealed an apocrine cystadenoma, basaloid follicular proliferation, and sebaceoma. Also, it is important to select the appropriate biopsy site and size when evaluating a patient for secondary neoplasms within their nevus sebaceous. Indeed, more than one biopsy may be required if additional diagnoses are suspected.

A morbilliform drug eruption is the most common condition leading to a dermatology consultation for a patient in the hospital. Timing is an important diagnostic tool since the onset of a skin rash usually takes place within days-to-weeks of the start of the implicated drug. A comprehensive, thorough, and reliable drug history by the clinician is essential. Therefore, to assist in the task of determining the causative medication of a new skin rash in a hospitalized patient, the creation of a drug calendar is recommended. The development of an electronic version of the drug calendar offers several benefits over the manual version. As the use of electronic medical records continues to become the standard in medicine, the electronic drug calendar will serve as an invaluable tool for the diagnosis of drug hypersensitivity.

The nail plate flag sign is a distinctive nail plate change that appears as white, red, white, and red sequential transverse bands beginning at the proximal nail fold. This distinctive nail change was initially described in patients with diabetes mellitus and leprosy; indeed, it was considered to be characteristic, but not diagnostic of leprosy. Subsequently, the flag sign was observed in patients with vitiligo. The flag sign has recently been noted in two men following heart transplantation. In summary, the flag sign is a unique nail change that has occurred in patients with autoimmune disorders, infection, and post transplantation surgery associated with immunosuppressive therapy to prevent organ rejection.

Platelet-rich plasma, which contains numerous growth factors that promote hair growth, is a nonsurgical treatment available for patients with androgenetic alopecia. However, neither the quantity nor the location and depth of platelet-rich plasma placement in the scalp is uniform; in addition, multiple painful injections are required. Vertical uniform channels from the skin surface into the dermis, created by ablative laser fractional photothermolysis, can be used to enhance the cutaneous delivery of medications. This technique — referred to as laser assisted drug delivery — may provide an efficacious means for the administration of platelet-rich plasma to the scalp. It would not only enable the uniform placement of platelet-rich plasma in the dermis (instead of inadvertently in the subcutaneous fat) of androgenetic alopecia patients' scalps, but also eliminate the injection-associated pain. In addition, the topical application of either bimatoprost or minoxidil or both could also be enhanced with laser assisted drug delivery. In conclusion, to potentially maximize the stimulation of hair growth, laser assisted drug delivery of platelet-rich plasma — with or without bimatoprost and/or minoxidil — should be considered in patients with androgenetic alopecia in order to effectively deliver the agents to the dermis where the bulge area of the hair follicles is located.

Metastatic basal cell cancer (BCC) is an ultra-rare malignancy with no approved therapies beyond Hedgehog inhibitors. We characterized the genomics, tumor mutational burden (TMB), and anti-PD-1 therapy responses in patients with locally advanced or metastatic BCC. Overall, 2,039 diverse cancer samples that had undergone comprehensive genomic profiling (CGP) were reviewed. Eight patients with locally advanced/metastatic BCC were identified (two had two CGP analyses; total, 10 biopsies). Two tumors demonstrated PD-L1 amplification. Seven patients had >1 actionable alteration. The TMB (mutations/mb) (median (range)) was 90 (3-103) for the BCCs versus 4 (1-860) for 1637 cancers other than BCC (P < 0.0001). Median progression-free survival (PFS) for all four patients treated with PD-1 blockade was 10.7 months (range, 3.8 to 17.6+ months); three patients had an objective response. In conclusion, advanced/metastatic BCC often has biological features (high TMB; PD-L1 amplification) predictive of immunotherapy benefit, and patients frequently respond to PD-1 blockade.

Osteoma cutis, the development of bone in the dermis and/or subcutaneous fat, can occur as either a primary or secondary condition. Perforating osteoma cutis is rare. A man with a solitary lesion of perforating osteoma cutis is described and the features of individuals with a single perforating osteoma cutis skin lesion are reviewed. A solitary lesion of either primary or secondary perforating osteoma cutis has only been observed in two men and one woman; the lesions had been present from less than one month to 19 or 20 years prior to establishing the diagnosis. The lesion was either located on the forehead (two men) or the breast (one woman). The erythematous (two lesions) or flesh-colored nodules ranged in size from 8×8 millimeters to 1.5×0.5 centimeters. Each had epidermal perforation by bone through a central area that was either crateriform or crusted or keratotic. The clinical differential diagnosis included keratoacanthoma, phlebolith, pilomatricoma, pilomatrical carcinoma, and squamous cell carcinoma. The perforating osteoma cutis lesion was successfully treated with either excision or shave biopsy without recurrence at either 10 or 12-months follow-up.

Genitogluteal porokeratosis is a disorder of keratinization that may present in men in their fourth decade of life. We describe a 52-year-old human immunodeficiency virus (HIV)-positive man with history of anal squamous cell carcinoma who developed verrucous lesions on the buttocks and genitals. The buttock lesions presented shortly after radiotherapy for anal carcinoma a decade prior, whereas the genital lesions presented three months prior in areas treated with injectable medication for erectile dysfunction. Skin biopsy revealed a cornoid lamella, leading to the diagnosis of genitogluteal porokeratosis. The buttock lesions were treated with shave excision and the genital lesions were treated with topical agents. Using the PubMed database, a literature search was performed with combinations of the following key words: acuminata, condyloma, cornoid lamella, genital, genitogluteal, HIV, penile, porokeratosis, verrucous, vulvar. The generated papers and their references were reviewed. To the best of our knowledge, we present the first reported case of genitogluteal porokeratosis in an HIV-positive man. Notably, these lesions developed in sites of prior radiation or injection. This condition should be included in the differential diagnosis of chronic lesions of the genitals and buttocks in patients with HIV and/or history of radiation treatment and/or trauma to the genitogluteal region.

Staphylococcus lugdunensis is a part of the normal skin flora. However, this organism can be a pathogen in certain situations such as advanced age or immunosuppression. Further study regarding situations in which this bacterium becomes a pathogen is warranted.

5-fluorouracil, a fluoropyrimidine antineoplastic drug, is used to topically treat actinic keratoses. Local skin reactions to the medication are common and anticipated. However, severe adverse events from topical 5-fluorouracil are rare and unexpected. A 69-year-old man with a lower lip actinic keratosis developed severe neutropenia on day 11 of topical 5-fluorouracil treatment — after 14 applications. After receiving a subcutaneous injection of filgrastim, his neutrophil count normalized. The PubMed database was used to search the following terms: agranulocytosis, cream, 5-fluorouracil, granulocytopenia, neutropenia, severe, systemic, topical, and toxicity. The papers, and relevant cited references, generated were reviewed. Systemic reactions to topical 5-fluorouracil included angioedema, melanonychia, neurologic conditions (such as acute cerebellar syndrome, headaches, and peripheral neuropathy exacerbation), taste alteration, and systemic toxicity requiring hospitalization (including severe neutropenia). One of the individuals (a man with severe neutropenia and other symptoms) also had a deficiency of dihydropyrimidine dehydrogenase, the enzyme that catalyzes the rate-limiting step in 5-fluorouracil metabolism. Evaluation for dihydropyrimidine dehydrogenase deficiency is not routinely performed in patients receiving systemic or topical 5-fluorouracil. Also, the incidence of potentially severe 5-fluorouracil-induced toxicity associated with topical application of the drug may be greater than documented.

Severe bullous eruptions in systemic lupus erythematosus (SLE) patients include bullous SLE, Rowell syndrome, toxic epidermal necrolysis (TEN), and TEN-like eruption of acute cutaneous lupus (TEN-like ACLE). TEN-like ACLE, a rare manifestation of SLE that closely mimics TEN, can be distinguished by characteristic clinical and laboratory findings. A 27-year-old man with SLE who developed TEN-like ACLE after initiating mycophenolate mofetil for active SLE is reported. The reports of 37 women and six men  including our patient with TEN-like ACLE were also reviewed. The diagnosis of SLE or subacute cutaneous lupus erythematosus was either previously confirmed or established at the time of diagnosis of TEN-like ACLE in 41 patients. Fever was present in 59% of patients. The onset of TEN-like ACLE was either subacute (73%) or acute (27%). Thirteen cases did not clarify the nature of disease onset. The skin lesions often presented initially on sun-exposed sites (29 patients) and involved one or more mucous membranes (21 patients). A new medication may have caused the TEN-like ACLE in 67% of the patients. Systemic corticosteroids either alone or combined with hydroxychloroquine, intravenous immunoglobulin, or mycophenolate mofetil were the most commonly used treatment. Patients with TEN-like ACLE patients had an 89% survival.

Subungual amelanotic melanoma can masquerade as onychomycosis. Recently a man whose amelanotic nail bed melanoma presented as persistent onychodystrophy was reported in the Dermatology Online Journal. The patient had a persistent nail dystrophy; culture and biopsy of the nail demonstrated Candida and dermatophyte infection, respectively. However, he subsequently presented with a nodule that was biopsied and demonstrated melanoma. Similar to that patient, we recently described a 67-year-old woman with a four-year history of persistent nail dystrophy of the left fourth fingernail who had a periodic acid-Schiff staining of the nail plate demonstrating fungal hyphae. Her nail plate subsequently detached, demonstrating a friable nodule; a biopsy of the nodule demonstrated melanoma. In conclusion, in individuals with new morphologic changes to a dystrophic nail or with persistent nail dystrophy despite appropriate therapy, it is important for clinicians to consider performing additional evaluation and possible biopsy to exclude malignancy.

Androgenic alopecia (AGA) is a chronic, progressive condition affecting millions of individuals worldwide. Treatment modalities for AGA are limited and our understanding of the pathophysiology underlying the disease is still developing. Platelet-rich plasma (PRP), an autologous collection of concentrated platelets and their respective growth factors, has demonstrated efficacy in limiting AGA. The current understanding of AGA pathogenesis is summarized, including our current understanding regarding androgens, inflammation, and arrector pili muscle loss. Furthermore, the molecular pathways induced by PRP in the context of AGA are discussed to ascertain how PRP can prevent disease progression. Well-designed studies investigating the effect of PRP on AGA patients to provide insight on how PRP should be used to achieve consistent clinical results are also presented. Future investigations should focus on elucidating a unifying theory to connect the currently disparate avenues of AGA pathogenesis. PRP clinical trials should be based on standardized treatment protocols to establish generalizable results.

Streptococcus dysgalactiae subspecies equisimilis (SDSE) is a gram-positive, beta-hemolytic, large-colony-forming bacteria belonging to group C and G streptococci. It can be isolated in the normal flora of human skin, nasopharyngeal cavity, genitourinary, and gastrointestinal tracts. However, SDSE has been the cause of perianal bacterial infections associated with sexual practices. A 67-year-old man developed a penile bacterial infection secondary to SDSE. The infection presented as a painful erythematous patch on his penile distal shaft. He was successfully treated with oral cephalexin 500mg and topical mupirocin 2% ointment twice daily, for ten days. The infection resolved within ten days of treatment. Penile and perianal SDSE bacterial disease has been reported in five men, including the patient in this report. The perianal area was involved in 80 percent (4/5) of men; concurrent infection in the gluteal area was present in two men. The probable route of transmission was oral-anal (two men) or oral-genital (one man). All of the mens SDSE infections completely resolved after treatment with antibiotics. In conclusion, SDSE can cause penile and perianal bacterial disease, perhaps more frequently in individuals that receive unprotected fellatio and anilingus from asymptomatic or symptomatic carriers of the organism in their oropharynx.

Scabies surrepticius is a unifying term that represents non-classical presentations of scabies mite infestation. A patient with scabies surrepticius is described: a man with scabies masquerading as prurigo nodularis. The 91-year-old man had metastatic prostate cancer and presented with diffuse pruritic nodules. Prurigo nodularis was suspected; however, the biopsy revealed scabies mites in the stratum corneum. He was successfully treated with topical permethrin 5% cream and oral ivermectin. In addition, the features of a woman with scabies mimicking systemic lupus erythematosus are summarized. The 47-year-old woman had idiopathic thrombocytopenic purpura and presented with malar erythema and a positive antinuclear antibody (titer 1:320). A diagnosis of systemic lupus erythematous was entertained until skin scraping and mineral oil preparation revealed scabies mites; she was successfully treated with oral ivermectin. In conclusion, Sarcoptes scabiei infestation can present with atypical clinical morphology and an absence of classical lesions such as burrows conventionally distributed in the interdigital web spaces, volar wrists, periumbilical area, or genitalia. Scabies surrepticius is a term that has been designated to describe these unusual presentations. Prurigo nodularis and systemic lupus erythematosus can be added to the litany of conditions masquerading as scabies and are included amongst the guises of scabies surrepticius.