Importance:Direct immunofluorescence (DIF) testing has been an important ancillary tool for the diagnosis of various inflammatory mucocutaneous conditions for more than 50 years. Current DIF test panels are based on historical clinical descriptions; few studies have rigorously addressed preanalytical, analytical, and/or postanalytical aspects, and even fewer have been replicated or validated. Recent unresolved key issues include whether DIF testing and test panels should be triaged or truncated based on clinical indication or histopathologic findings. Objective:To assess levels of consensus regarding practical aspects of DIF testing among immunodermatology testing specialists in the US. Design, Setting, and Participants:Using modified Delphi methods with a priori characterized criteria, a survey containing 54 statements pertaining to DIF testing was created and distributed to assess consensus. Statements not initially reaching consensus were discussed in 2 live virtual sessions, which were supplemented by relevant literature review and free-text survey comments. These statements were then reassessed in a second survey. Immunodermatology testing specialists in US academic institution-based and independent laboratories were invited based on serving as immunodermatology laboratory medical directors, authoring pertinent literature, or delivering relevant talks at major conferences or by referral. The first survey was conducted from January to February 2024, and the second survey was conducted from March to April 2024. Main Outcomes and Measures:The primary measured outcome was degree of consensus for various DIF testing practice, including DIF testing triage by histopathology/dermatopathology findings and DIF testing panel tailored truncations by clinical indication. Results:A total of 23 respondents to the survey invitation had a mean (SD) of 18.5 (11.1) years and median (range) of 20.0 (1.5-46.0) years in immunodermatology laboratory practice. Consensus was achieved for 46 of 54 statements (85.2%) in the initial survey and for an additional 4 statements in the second survey (50 of 54 [92.6%]). Strong consensus was found against tailored truncation of DIF panel based on the clinical indication in the first survey round. The general acceptability of triaging specimens for DIF testing based on histopathology findings remained without consensus after both surveys. Conclusions and Relevance:Overall, participating US specialists in immunodermatology laboratory testing agreed on many practical aspects of DIF testing, including matters not queried previously. The findings also revealed areas of continued controversy and identified issues for prioritized future study.

Reports of permanent chemotherapy-induced alopecia (pCIA), defined as the absence or incomplete regrowth of hair for ≥6 months following completion of chemotherapy, are increasing. Most often associated with taxane-based chemotherapies and endocrine therapies, it affects 42% of breast cancer survivors.1,2 While most patients present with diffuse hair thinning, our patient presented with brown plaques in addition to hair loss.

Background As more people become vaccinated against the SARS-CoV-2 virus, reports of delayed cutaneous hypersensitivity reactions are beginning to emerge. Methods In this IRB-approved retrospective case series, biopsy specimens of potential cutaneous adverse reactions from the Pfizer-BioNTech or Moderna mRNA vaccine were identified and reviewed. Clinical information was obtained through the requisition form, referring clinician, or medical chart review. Results Twelve cases were included. Histopathological features from two injection-site reactions showed a mixed-cell infiltrate with eosinophils and a spongiotic dermatitis with eosinophils. Three biopsy specimens came from generalized eruptions that showed interface changes consistent with an exanthematous drug reaction. Three biopsy specimens revealed a predominantly spongiotic pattern, consistent with eczematous dermatitis. Small-vessel vascular injury was seen in two specimens, which were diagnosed as urticarial vasculitis and leukocytoclastic vasculitis, respectively. There were two cases of new-onset bullous pemphigoid supported by histopathological examination and direct immunofluorescence studies. Eosinophils were seen in 10 cases. Conclusions Dermatopathologists should be aware of potential cutaneous adverse reactions to mRNA-based COVID-19 vaccines. Histopathological patterns include mixed-cell infiltrates, epidermal spongiosis, and interface changes. Eosinophils are a common finding but are not always present. Direct immunofluorescence studies may be helpful for immune-mediated cutaneous presentations such as vasculitis or bullous pemphigoid.

Dermatomyositis (DM) is an inflammatory myositis that commonly presents with a characteristic skin eruption, which can occur even in the absence of muscle inflammation. Cutaneous manifestations tend to be more severe in a recently described DM-specific autoantibody subtype, transcription intermediary factor 1-γ (TIF1-γ) DM.1 As DM has the potential to cause significant pruritus, photosensitivity, and dyspigmentation, TIF1-γ-associated DM may be psychologically distressing to patients and have a negative effect on overall quality of life.

Papillary dermal elastolysis has been described in the setting of experimental combination nivolumab and cabiralizumab immunotherapy. We report a third patient with distinctive, generalized atrophic macules that developed after a morbilliform eruption during a clinical trial for treatment of metastatic pancreatic adenocarcinoma. Histopathological findings demonstrated diminished elastic fibers in the papillary dermis, associated with a histiocyte-rich infiltrate and increased dermal mucin, features that should clue the dermatopathologist to this condition.

POINTS• Cholesterol embolization may occur in proximal locations, and index of suspicion should be high in patients who are at risk.• Several biopsies may be necessary to make a diagnosis of cholesterol emboli.FIGURE 1. Cutaneous eschars.Geographic eschars on the lower abdomen and mons region.

Background: Dermatopathologists sometimes encounter patients with features of psoriasis vulgaris and additional changes of eczematous dermatoses. These cases are challenging to diagnose, and the clinical implications are unclear. In the age of targeted therapy, it is important to improve our understanding of these findings so that patients are managed appropriately. Objective: To characterize the clinical characteristics, histopathological features, diagnostic workup, successful treatment, and outcomes of patients with overlapping histopathologic features of psoriasis vulgaris and eczema. Methods: We conducted a retrospective chart review of 20 patients who had received the histopathologic diagnosis of psoriasis vulgaris with eczematous changes noted on skin biopsy. A database that included information about clinical characteristics, comorbidities, histopathological features, diagnostic workup, treatment modalities, and outcomes was created and analyzed. Results: Twenty patients were included in this study, with an average age of 57.3 years. After clinicopathologic correlation, most patients were diagnosed with psoriasis (85%), and the remainder were determined to have an eczematous dermatitis. Thirty-five percent of patients were diagnosed with allergic contact dermatitis, either in combination with psoriasis (6 patients) or alone (1 patient). Topical glucocorticoids were the most common effective therapy used, and systemic therapies were required in nearly half of patients for successful treatment. Conclusion: This study offers insights into the clinically and histopathologically challenging diagnosis of psoriasis vulgaris with eczematous changes and offers the diagnostic term “eczematized psoriasis” to describe these patients. The presence of allergic contact dermatitis should be considered in these patients.

Lichen planus (LP) is an inflammatory dermatosis that presents with pruritic papules, with LP lesions along the lines of Blaschko representing a rare variant.1,2 There are several terms for this entity, including linear LP, Blaschkolinear LP, and Blaschkoid LP. To minimize confusion and be more consistent with its distribution, we suggest this variant be termed what it truly is: Blaschkoid lichen planus. Although most cases of Blaschkoid LP have a unilateral distribution, we report a case of bilateral LP in a Blaschkoid distribution that subsequently resolved after treatment with oral glucocorticoids.

Direct immunofluorescence (DIF) remains a valuable tool that may be underused because of perceived challenges in the interpretation, limitations, and processing of DIF specimens. The aim of this review is to provide a practical guide for appropriately incorporating DIF in a variety of clinical diseases, such as autoimmune blistering disorders. In vasculitis, the role of DIF continues to evolve, particularly in the setting of IgA vasculitis. Although typically not indicated for the workup of connective tissue disease, DIF may be helpful in cases with negative serologies, nondiagnostic histologic findings, or scarring alopecia. Practical pearls for biopsy technique, specimen handling, and storage are also discussed.

To the Editor: IgG/IgA pemphigus describes a rare autoimmune blistering disorder characterized by clinical and histopathologic features of pemphigus mediated by IgG and IgA.1 Controversy exists as to whether it is a distinct disease, a transitional phase along a spectrum of IgG pemphigus to IgA pemphigus, or a heterogeneous disorder.1 In an effort to elucidate its clinical and histopathologic features, a retrospective study of 44 patients with IgG/IgA pemphigus was conducted.

To the Editor: During the coronavirus disease 2019 pandemic, many aspects of dermatology resident education have been converted to an online format.1Oldenburg R. Marsch A. Optimizing teledermatology visits for dermatology resident education during the COVID-19 pandemic.J Am Acad Dermatol. 2020; 82: e229Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar Dermatopathology, comprising up to 30% of the training curriculum,2Hinshaw M. Hsu P. Lee L.Y. Stratman E. The current state of dermatopathology education: a survey of the Association of Professors of Dermatology.J Cutan Pathol. 2009; 36: 620-628Crossref PubMed Scopus (20) Google Scholar already has a foothold in virtual learning, and virtual microscopy will completely replace glass slide microscopy on the dermatology board examination. Many departments, including ours, have curated virtual slide libraries to supplement education. In addition, the American Society of Dermatopathology has provided a list of freely accessible virtual slide libraries, lectures, and textbook-related content for self-study3The American Society of Dermatopathology COVID-19 resources.https://www.asdp.org/about-asdp/covid-19-resources/Date accessed: April 29, 2020Google Scholar (https://www.asdp.org/about-asdp/covid-19-resources/). Nevertheless, optimal dermatopathology education includes faculty interaction. With social distancing likely to remain in place for an extended period, instruction at a multiheaded microscope is not feasible. At our institution, we have combined video conferencing (eg, Webex or Zoom) with either glass slide microscopy or virtual microscopy for weekly didactics, review sessions, or routine sign-out (Fig 1). When the dermatopathologist shares the contents of the computer screen, the multiheaded microscope is simulated as residents view the same image without issues of focus, lighting, or available scope heads. Residents are able to participate either through speaking or the chat function. Questions posed through the chat function are reviewed periodically and read aloud before answers are given. These live slide sessions can be recorded for playback. However, the quality of the experience partly depends on a robust technical infrastructure, which includes hardware, systems and application software, and data network and storage. For projecting glass slide microscopy, a digital single-lens reflex (SLR) camera can be attached to a trinocular microscope through T-mount or C-mount adapters that are specific to the equipment brand. Images are transferred to a computer via a USB image-capture device (Table I). This approach is most suitable for teaching during routine sign-out or didactics with unknown glass slides. For virtual slides, our current platform is Aperio ImageScope, a whole-slide viewer that allows image rotation, magnification changes, and annotations. As opposed to static images with preselected relevant features, residents develop their diagnostic skills by searching the whole slide before progressing to targeted detection approaches4Shahriari N. Grant-Kels J. Murphy M.J. Dermatopathology education in the era of modern technology.J Cutan Pathol. 2017; 44: 763-771Crossref PubMed Scopus (16) Google Scholar during self-study. Features specific to ImageScope include fixed rather than continuous magnification and fixed-angle rotation instead of free manipulation, which some platforms allow, such as Leica's WebViewer. Last, multiple cases can be displayed simultaneously by window tiling, with the option of zoom synchronization. The ability to compare and contrast cases is critical to address areas of diagnostic confusion.Table IApproximate costs for virtual projection of glass slidesEquipmentPrice, approximate, $Digital SLR camera400-2000T-mount adapter500C-mount adapter800Trinocular microscope head3500USB image capture device350SLR, Single-lens reflex; USB, universal serial bus. Open table in a new tab SLR, Single-lens reflex; USB, universal serial bus. For dermatopathologists concerned about the technologic challenges of virtual microscopy, those participating in a virtual microscopy educational workshop rated the ease of navigation of virtual microscopy higher than that of glass slide microscopy.5Brick K.E. Comfere N.I. Broeren M.D. Gibson L.E. Wieland C.N. The application of virtual microscopy in a dermatopathology educational setting: assessment of attitudes among dermatopathologists.Int J Dermatol. 2014; 53: 224-227Crossref PubMed Scopus (16) Google Scholar Educators should also be mindful of the limitations of remote teaching, such as delayed responses to digital communications or loss of nonverbal feedback, which is another important component of learning. Anecdotal and solicited feedback from our residents has provided iterative optimization of our virtual approach and has been overwhelmingly positive. In this uncertain time, we have observed the resourcefulness of our colleagues in educating our trainees. We hope our experience will similarly offer a framework from which residents can learn dermatopathology. Optimizing teledermatology visits for dermatology resident education during the COVID-19 pandemicJournal of the American Academy of DermatologyVol. 82Issue 6PreviewTo the Editor: After an outbreak of unexplained pneumonia cases in Wuhan, China, in December 2019, the World Health Organization officially named the disease caused by the culprit virus as coronavirus disease 2019 (COVID-19).1 Faced with a global public health emergency, dermatology practices are now using telemedicine to limit in-person appointments to reduce transmission of COVID-19 per interim guidance from the Centers for Disease Control and Prevention and the American Academy of Dermatology. Full-Text PDF

A 57-year-old woman presented with a progressively enlarging irregular black patch of 1-year duration on the left fourth toenail (Fig 1). The patient denied new medications, history of trauma, or previous nail dyspigmentation. Proximal and lateral nail folds were not involved and pigmentation of the hyponychium was not evident. The patch could not be removed with scratching of the nail plate. Dermoscopy revealed nonlongitudinal, black to brown, reticular pigmentation with overlying white scale and distal onycholysis (Fig 2).Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT) Question 1: What is the most likely diagnosis?A.Nevus of the nail matrixB.Fungal melanonychiaC.Subungual melanomaD.Trauma-related nail plate hemorrhageE.Exogenous pigment Answers:A.Nevus of the nail matrix—Incorrect. Nevi of the nail matrix are a common cause of longitudinal melanonychia in children and are characterized by uniform nests of cytologically banal melanocytes. Nevi tend to present with homogenous brown to black longitudinal bands. On dermoscopy, small dark granules less than 0.1 mm in diameter may be visualized and represent intracellular melanin inclusions.B.Fungal melanonychia—Correct. Fungal melanonychia is a rare nail infection caused by fungal organisms that produce melanin pigment, most commonly Trichophyton rubrum and Scytalidium dimidiatum.1Piraccini B.M. Dika E. Fanti P.A. Tips for diagnosis and treatment of nail pigmentation with practical algorithm.Dermatol Clin. 2015; 33: 185-195Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar,2Finch J. Arenas R. Baran R. Fungal melanonychia.J Am Acad Dermatol. 2012; 66: 830-841Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar The dystrophic nail changes, onycholysis, subungual hyperkeratosis, and yellowish discoloration of the involved nail (and nearby nails) point to the clinical possibility of fungal infection. Additionally, the lack of trauma and the nonlongitudinal clinical appearance further support this diagnosis.C.Subungual melanoma—Incorrect. Subungual melanoma is an important cause of melanonychia, with concerning features that include presentation in the fifth to seventh decade of life, sudden onset or widening of irregular brown-black longitudinal bands, and pigment extension to the lateral or proximal nail fold (Hutchinson sign).1Piraccini B.M. Dika E. Fanti P.A. Tips for diagnosis and treatment of nail pigmentation with practical algorithm.Dermatol Clin. 2015; 33: 185-195Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar,3Ko D. Oromendia C. Scher R. Lipner S.R. Retrospective single-center study evaluating clinical and dermoscopic features of longitudinal melanonychia, ABCDEF criteria, and risk of malignancy.J Am Acad Dermatol. 2019; 80: 1272-1283Abstract Full Text Full Text PDF PubMed Scopus (15) Google ScholarD.Trauma-related nail plate hemorrhage—Incorrect. Nail plate hemorrhage is a common finding and often presents with red to maroon discoloration. Patients often report a history of trauma, anticoagulant use, or both. The diagnosis can be confirmed with nail plate clipping.1Piraccini B.M. Dika E. Fanti P.A. Tips for diagnosis and treatment of nail pigmentation with practical algorithm.Dermatol Clin. 2015; 33: 185-195Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar,4Braun R.P. Baran R. Le Gal F.A. et al.Diagnosis and management of nail pigmentations.J Am Acad Dermatol. 2007; 56: 835-847Abstract Full Text Full Text PDF PubMed Scopus (208) Google ScholarE.Exogenous pigment—Incorrect. Exogenous pigment includes that from tobacco, dirt, potassium permanganate, tar, iodine, and silver nitrate. These substances may cause a brown to black pigmentation of the nails and can often be easily scratched off. These features are lacking in the presented case.1Piraccini B.M. Dika E. Fanti P.A. Tips for diagnosis and treatment of nail pigmentation with practical algorithm.Dermatol Clin. 2015; 33: 185-195Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar Question 2: What are key dermoscopic features of the correct diagnosis?A.Longitudinal brown to black lines with irregular color, spacing, and thickness, with pigment extension onto the hyponychium, revealing a parallel ridge patternB.Gray homogenous band consisting of multiple thin homogeneous gray linesC.Red-black globules along proximal and lateral margins of homogenous pigment that lacks melanin granulesD.Light- to dark-brown parallel striae that extend beneath a translucent eponychiumE.White or yellow streaks, nonlongitudinal homogenous pattern, and reverse triangular pattern Answers:A.Longitudinal brown to black lines with irregular color, spacing, and thickness, with pigment extension onto the hyponychium, revealing a parallel ridge pattern—Incorrect. Dermoscopic features suggestive of subungual melanoma may include irregular longitudinal brown to black lines with asymmetry in color, spacing, and thickness. Lines also may show parallelism disruption or blood spots.B.Gray homogenous band consisting of multiple thin homogeneous gray lines—Incorrect. This dermoscopic feature is a sign of benign melanocytic activation and may be observed in several diagnoses, such as drug-induced pigmentation or ethnic-type melanonychia.1Piraccini B.M. Dika E. Fanti P.A. Tips for diagnosis and treatment of nail pigmentation with practical algorithm.Dermatol Clin. 2015; 33: 185-195Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar,4Braun R.P. Baran R. Le Gal F.A. et al.Diagnosis and management of nail pigmentations.J Am Acad Dermatol. 2007; 56: 835-847Abstract Full Text Full Text PDF PubMed Scopus (208) Google ScholarC.Red-black globules along proximal and lateral margins of homogenous pigment that lacks melanin granules—Incorrect. Homogenous red-maroon pigmentation with round globules at the periphery likely represents subungual hematoma. However, red-maroon pigmentation that does not resolve with nail growth may require additional histopathologic examination because of the concern for subungual melanoma.4Braun R.P. Baran R. Le Gal F.A. et al.Diagnosis and management of nail pigmentations.J Am Acad Dermatol. 2007; 56: 835-847Abstract Full Text Full Text PDF PubMed Scopus (208) Google ScholarD.Light- to dark-brown parallel striae that extend beneath a translucent eponychium—Incorrect. This feature is known as pseudo-Hutchinson sign and is a common feature of nail matrix nevi, often observed in younger adults and children.3Ko D. Oromendia C. Scher R. Lipner S.R. Retrospective single-center study evaluating clinical and dermoscopic features of longitudinal melanonychia, ABCDEF criteria, and risk of malignancy.J Am Acad Dermatol. 2019; 80: 1272-1283Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar Other features of a nevus include the presence of melanin inclusion granules, regular nail band pattern, parallel lines, and uniform band thickness and spacing.4Braun R.P. Baran R. Le Gal F.A. et al.Diagnosis and management of nail pigmentations.J Am Acad Dermatol. 2007; 56: 835-847Abstract Full Text Full Text PDF PubMed Scopus (208) Google ScholarE.White or yellow streaks, nonlongitudinal homogenous pattern, and reverse triangular pattern—Correct. These features, along with subungual hyperkeratosis, yellow or multicolor pigmentation, and white scale, are more significantly associated with fungal melanonychia than sources of melanocyte activation or melanocyte hyperplasia.5Ohn J. Choe Y.S. Park J. Mun J.-H. Dermoscopic patterns of fungal melanonychia: a comparative study with other causes of melanonychia.J Am Acad Dermatol. 2017; 76: 488-493.e2Abstract Full Text Full Text PDF PubMed Scopus (24) Google Scholar The presence of irregular reticular pigmentation has not previously been described, but may represent another dermoscopic feature of fungal melanonychia. Additional studies are needed to confirm the diagnostic accuracy of this feature. Question 3: What is the best next step in confirming the diagnosis?A.Dermoscopic short-term monitoring aloneB.Nail matrix biopsyC.Nail clippingD.ReassuranceE.Amputation Answers:A.Dermoscopic short-term monitoring alone—Incorrect. Although monitoring for pigment clearance is important, short-term monitoring with dermoscopy does not confirm the diagnosis of fungal melanonychia. Pigmented onychomycosis requires antifungal treatment to assist with infection clearance, allowing pigment to clear as the nail grows out.2Finch J. Arenas R. Baran R. Fungal melanonychia.J Am Acad Dermatol. 2012; 66: 830-841Abstract Full Text Full Text PDF PubMed Scopus (61) Google ScholarB.Nail matrix biopsy—Incorrect. If clinical or dermoscopic features were concerning for subungual melanoma, a nail matrix biopsy would be recommended as the best next step. Given the lack of melanoma-specific clinical or dermoscopic features, alternative diagnostic evaluation should be performed first. However, a nail matrix biopsy may be considered for cases refractory to antifungal treatment to rule out subungual melanoma.2Finch J. Arenas R. Baran R. Fungal melanonychia.J Am Acad Dermatol. 2012; 66: 830-841Abstract Full Text Full Text PDF PubMed Scopus (61) Google ScholarC.Nail clipping—Correct. Nail clipping is the best next step to confirm onychomycosis. Nail clipping in this patient case demonstrated a dystrophic nail plate with subungual parakeratosis and neutrophil collections. Fontana-Masson stain and periodic acid–Schiff stain with diastase revealed numerous fungal organisms that contained melanin, preferentially located on the nail plate surface. However, pigment associated with fungus is often best observed on hematoxylin-eosin staining of a nail clipping.D.Reassurance—Incorrect. Reassurance alone without follow-up or treatment would not be appropriate for this patient. Additionally, surveillance for pigment clearance is important to ensure that the nail pigmentation is not associated with an underlying malignancy.E.Amputation—Incorrect. Amputation of the involved digit may be considered for the treatment of locally advanced melanoma. Amputation is not recommended for onychomycosis, the diagnosis presented in this patient case.4Braun R.P. Baran R. Le Gal F.A. et al.Diagnosis and management of nail pigmentations.J Am Acad Dermatol. 2007; 56: 835-847Abstract Full Text Full Text PDF PubMed Scopus (208) Google Scholar

A 30-year-old man presented with a 6-month history of an exophytic mass growing on the lower mid-back (Figure 1). It was initially suspected to be verruca vulgaris, and he had been referred to a specialty clinic for sexually transmitted infections to confi rm it. The lesion was occasionally tender to palpation and bled spontaneously. Physical examination revealed a 1.5-cm ulcerated, violaceous-to-erythematous polypoid nodule with overlying serous crust on the lower back. No pigmentation was noted within the mass or adjacent to the base of the lesion. Histopathologic examination of a shave biopsy specimen revealed: • An exophytic polypoid lesion with broad ulceration, composed of markedly atypical melanocytes in a sheet-like pattern throughout the dermis (Figure 2A) • Focal epidermal contiguity with atypical melanocytes arranged in single cells and nests in the epidermis (Figure 2B) • A mitotic rate of greater than 30 mitoses/ mm2 (Figure 2C) • Lymphovascular invasion (Figure 2D) • Melanocytes highlighted by S-100 protein on immunohistochemical staining. These fi ndings were diagnostic of melanoma, specifi cally the polypoid variant, with a tumor thickness of 5 mm. The patient was referred for wide local excision with sentinel lymph node biopsy, which demonstrated inguinal node involvement and BRAF mutation on immunostaining. Positronemission tomography–computed tomography, magnetic resonance imaging, and computed tomography of the head, chest, abdomen, and pelvis were unrevealing. The formal diagnosis was stage IIIC disease (T4bN1M0). The patient began immunotherapy with nivolumab. He was treated with this drug for 1 year and now is on active surveillance.

Lichen planopilaris (LPP) is a cicatricial alopecia that often causes permanent hair loss. Pioglitazone, a peroxisome proliferator activated receptor-gamma (PPAR- γ) agonist, has demonstrated immunomodulatory properties that may offer an effective treatment modality. This retrospective analysis describes 23 patients with LPP treated with adjunctive pioglitazone. Most (18/25) demonstrated significant reduction in patient-reported symptoms and clinical signs of inflammation. No adverse effects were reported.J Drugs Dermatol. 2019;18(12):1276-1279.

Inflammatory skin diseases encompass a vast array of conditions. The field continues to expand and evolve with resurgence of conditions, through newly recognized medication adverse effects, and via more detailed descriptions of known dermatoses. The importance of clinicopathologic correlation and an up to date knowledge of dermatologic conditions cannot be overstated. This review focuses on an array of recent important developments in the histologic diagnosis of inflammatory conditions that affect the skin.

"Eosinophils are absent in psoriasis" has been dogma for generations; yet, there is little published to support this statement. Two recent studies examining the presence of eosinophils in psoriasis came to contrasting conclusions. We reviewed skin biopsies from 50 patients with clinically confirmed cases of psoriasis vulgaris to characterize the histologic features, with a focus on the number of eosinophils in the dermis. We noted the presence of eosinophils in nearly half of our study population (n = 23, 46.0%). There was no significant association between the presence of eosinophils and degree of spongiosis (P = 0.405). Eosinophil density ranged from 0 to 8 per tissue section. The mean average eosinophil density was 1.04 (range: 0-8) per tissue section. Among cases with eosinophils, there were 73.9% (n = 17/23) of cases with 1-2 eosinophils, and 26.1% (n = 6) with 3-8 eosinophils. Mild to moderate spongiosis was noted in the majority of cases (n = 48; 96.0%). Eosinophils were only present in psoriasis cases with evidence of spongiosis (n = 23; 47.9%). We conclude that eosinophils are not an uncommon finding in the dermis of psoriasis vulgaris, although the number is often few. The presence of eosinophils should not preclude a diagnosis of psoriasis, particularly if other histologic features are supportive.

Cutaneous Crohn disease (CCD) is a rare dermatologic manifestation of Crohn disease and is defined as noncaseating, granulomatous skin lesions noncontiguous with the gastrointestinal tract. It most commonly affects the skin of the legs, although genital CCD is the most common presentation in children. Diagnosis of CCD is made by a combination of clinical and histopathological findings. Therapeutic options include topical, intralesional, and systemic corticosteroids as well as topical and systemic immunosuppressants and immunomodulators. Surgical excision may be considered for refractory cases. We report CCD in a 9-year old boy with penile swelling, granulomatous cheilitis-like lesions, and perianal plaques.

Laird, Mary E. BA; Lo Sicco, Kristen I. MD; Reed, Michael L. MD; Brinster, Nooshin K. MD Author Information

Superficial granulomatous pyoderma (SGP) is a rare condition that some regard as a variant of pyoderma gangrenosum (PG) given their clinical similarities; however, SGP is distinct in its cutaneous presentation, histology, lack of underlying disease, and prognosis. Treatment options have ranged from oral antibiotics to oral and intralesional steroids, immunomodulatory agents, and intravenous immunoglobulin (IVIG), among others. We describe a case of long-standing SGP that responded to conservative management with Unna boot and intralesional steroid injections.

Systemic lupus erythematosus (SLE) and antineutrophil cytoplasmic antibody-associated vasculitis (AAV) overlap syndrome is an inflammatory disorder with a mixed presentation that is characterized by clinical features of both SLE and AAV. Although renal disease predominates, any organ system in the body may be affected. Neurologic manifestation in patients with SLE–AAV overlap syndrome is rare and has only been previously documented as cerebral ischemia. We report a patient with SLE–AAV overlap syndrome diagnosed based on clinical, serologic and biopsy-proven histologic findings who presented with subarachnoid hemorrhage (SAH) secondary to ruptured right anterior cerebral artery aneurysm. To the authors’ knowledge, this is the first reported case of SLE–AAV overlap syndrome diagnosed in a patient with a SAH due to an intracranial aneurysm. Neurologic involvement in patients with SLE–AAV overlap syndrome is uncommon and has not been well-studied. Clinicians who encounter patients with neurologic signs that present with symptoms and a serologic profile that correspond to both SLE and AAV criteria, should consider the association between SLE–AAV overlap syndrome and a hemorrhagic stroke, specifically SAH.