Diagnostic value of Tzanck smear in various erosive, vesicular, and bullous skin lesions

Clinical management of bullous pemphigoid-The importance of cytology in diagnosis

Bullous pemphigoid (BP) is a common immune-mediated blistering disorder with predominant skin involvement and occasionally oral manifestations. Vesiculobullous lesions of the oral mucosa present with similar clinical features, and hence arriving at a clinical diagnosis is aided by a valuable chairside investigation, exfoliative cytology. Cytology done in the present case ruled out pemphigus because of the absence of Tzanck cells in the smear. Biopsy and direct immunofluorescence further confirmed the diagnosis of BP. Treatment initiated with systemic steroids and immunomodulators, along with oral topical application of triamcinolone acetonide resulted in complete remission in 2 months. This case report highlights the role of cytology in the diagnosis of vesiculobullous lesions and management protocol for BP patients presenting with simultaneous skin and oral lesions.

Classic bedside diagnostic techniques

Correctly performing bedside diagnostic tests is an important fundamental skill for practicing dermatologists. Even with new technologies, bedside diagnostic tests have been useful in contemporary practice. When properly implemented, bedside diagnostic techniques can efficiently and economically aid in diagnosis and treatment. We have reviewed the most commonly used diagnostic procedures while considering them in their historical context, outlined the procedures for performing the tests, and discussed the relevance and regulatory requirements of the tests.

Current status and prospects for the diagnosis of pemphigus vulgaris

Introduction: Pemphigus vulgaris (PV) is an intraepidermal autoimmune bullous disease (AIBD) characterized by autoantibodies against desmosomal adhesion proteins, most commonly desmoglein (Dsg)3, leading to the suprabasal cleft formation and acantholysis.Areas covered: Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) studies display the intercellular deposition of IgG/C3 throughout the epidermis and presence of circulating autoantibodies respectively, as a net-like pattern. However, the target antigen remains unknown using immunofluorescence techniques. Thanks to the development of Dsg ELISA, using recombinant technology, circulating antibodies against Dsg1 and 3 could be detected sensitively. It is possible to differentiate PV from pemphigus foliaceus (PF) using this assay. BIOCHIP mosaic and multivariant ELISA are two novel serologic methods with the added value of the ability to screen several AIBDs simultaneously.Non-Dsg1/3 antigens are also involved in the pathogenesis of PV and investigated more deeply thanks to the protein microarrays technique. Additionally, patients with high values of anti-Dsg1/3 may be lesion-free, suggesting the presence of nonpathogenic autoantibodies.Expert opinion: Newer diagnostic methods to replace traditional techniques should possess high sensitivity and specificity and be widely available, noninvasive, and relatively cheap. The newly developed methods need to be further evaluated before being recommended for routine use.

TzanckNet: a convolutional neural network to identify cells in the cytology of erosive-vesiculobullous diseases

Tzanck smear test is a low-cost, rapid and reliable tool which can be used for the diagnosis of many erosive-vesiculobullous, tumoral and granulomatous diseases. Currently its use is limited mainly due to lack of experience in interpretation of the smears. We developed a deep learning model, TzanckNet, that can identify cells in Tzanck smear test findings. TzanckNet was trained on a retrospective development dataset of 2260 Tzanck smear images collected between December 2006 and December 2019. The finalized model was evaluated using a prospective validation dataset of 359 Tzanck smear images collected from 15 patients during January 2020. It is designed to recognize six cell types (acantholytic cells, eosinophils, hypha, multinucleated giant cells, normal keratinocytes and tadpole cells). For 359 images and 6 cell types, TzanckNet made 2154 predictions. The accuracy was 94.3% (95% CI 93.4-95.3), the sensitivity was 83.7% (95% CI 80.3-87.0) and the specificity was 97.3% (95% CI 96.5-98.1). The area under the receiver operating characteristic curve was 0.974. Our results show that TzanckNet has the potential to lower the experience barrier needed to use this test, broadening its user base, and hence improving patient well-being.

Bedside Diagnostics for Infections: A Guide for Dermatologists

In dermatology, there are many bedside diagnostic tests that may aid in more rapid diagnosis and early initiation of appropriate therapy. When performed correctly, these bedside diagnostic tests can provide both sensitive and specific results. We discuss bedside diagnostic tests, such as the Tzanck smear, potassium hydroxide (KOH) preparation, and mineral oil preparation, with a specific focus on their use in diagnosing infectious dermatoses.

Detection of multinucleated giant cells in differentiated keratinocytes with herpes simplex virus and varicella zoster virus infections by modified Tzanck smear method

Herpes simplex virus (HSV) and varicella zoster virus (VZV) infections induce the formation of intraepidermal vesicles containing acantholytic cells and multinucleated giant cells in the skin. The Tzanck smear is most commonly used to diagnose cutaneous herpetic infections, but it leads to many false-positive and -negative results. This study aimed at establishing a method detecting much larger multinucleated giant cells using the Tzanck smear because these cells characterize the viral cytopathic effect in skin infections. Morphological changes were analyzed among several layers of keratinocytes with HSV- or VZV-related cutaneous lesions, clinically and in vitro. We compared the sensitivity of the Tzanck smear to detect large acantholytic cells using both the removed roof tissue part (our approach) and the floor of the lesion (conventional approach) of a fresh vesicle. Large acantholytic cells were detected 2.0-times more frequently in the removed roof tissue part of the vesicle than in the floor of the lesion. Round cells were much larger in the removed roof tissue part of the vesicle corresponding to the granular or prickle layer of the epidermis than in its floor of the lesion corresponding to the basal or prickle layer with the Tzanck smear. Differentiated cultured keratinocytes formed multinucleated giant cells by cell-to-cell fusion with resolution of cell membrane with VZV infection. Differentiated keratinocytes promote multinucleated giant cell formation by cell-to-cell fusion with HSV-1 or VZV infection. To increase the sensitivity, the Tzanck smear should be prepared from the removed roof tissue part of a fresh vesicle to detect multinucleated giant cells in herpetic infections.

Diagnostic value of cytology in oral ulcer and comparison with histopathology and direct immunofluorescence

Rapid diagnosis of pemphigus vulgaris (PV) is an important task in patient's prognosis and treatment. Although PV is routinely diagnosed through investigation of pathology specimens and direct immunofluorescence assays, Tzanck smear can be used as rapid, inexpensive, and easily used test to confirm its clinical diagnosis. This study aimed to determine the diagnostic value of Tzanck smear in erosive oral lesions of PV and also determine its sensitivity and specificity for diagnostic purposes. A total of 68 patients with erosive/ulcerated oral lesions were included in this study and divided into PV (case group) vs other causes of erosive oral lesions (control group). From all participants, two Tzanck smears were prepared for both Giemsa and hematoxylin-eosin (H&E) staining. For definite diagnosis, histopathology and direct immunofluorescence evaluations were performed based on clinical findings. The sensitivity of acantholytic cells in Tzanck smear of erosive oral lesions of PV cases was 80.5% (for both Giemsa and H&E staining), whereas specificity values of Giemsa and H&E staining were 84.6% and 96.3%, respectively. Based on our findings, the Tzanck smear of erosive oral lesions is a simple, quick, and inexpensive test for screening and primary diagnosis of PV.

Childhood Pemphigus Vulgaris: Report of Two Cases with Emphasis on Diagnostic Approach

Childhood pemphigus vulgaris (CPV) is a rare entity with clinical features and management primarily similar to those of adults; diagnosis may be difficult due to clinical similarity to other disorders such as herpetic gingivostomatitis which is more prevalent in this age group. We report two cases of CPV with emphasis on diagnostic approach. While treating such patients, it is imperative to diagnose CPV in the early stages to prevent serious morbidity and to adjust drug dosage to minimize side effects.

Delayed Diagnosis of Basal Cell Carcinoma of the Upper Lip: The Possible Role of Incidental Multinucleated Foreign Body Giant Cells

Herpes simplex and basal cell carcinoma (BCC) can have similar clinical presentations due to overlapping lesional morphology. We describe the unusual case of a BCC masquerading as herpes labialis due to a possible false-positive Tzanck smear. The confounding diagnosis led to a failed trial of valacyclovir and subsequent loss of the patient for 1 year before the lesion was biopsied and diagnosed as a BCC. This case report highlights the importance of careful inspection of herpetic lesions and that further investigation should be pursued if the etiology is uncertain or if the treatment is not yielding the expected results.

Diagnostic Utility and Pitfalls of Tzanck Smear Cytology in Diagnosis of Various Cutaneous Lesions

Aims:

Tzanck smear is an old but useful test for diagnosis of cutaneous dermatoses. The aim of this study was to highlight the potential usefulness and diagnostic pitfalls of Tzanck smear for diagnosis of cutaneous dermatoses and infections.

Materials and Methods:

This hospital based cross-sectional study was carried out on all Tzanck smears received for a period of twenty months (January 2014–August 2015). The smears were assessed to establish the utility of Tzanck smears in corroborating or excluding a diagnosis of immunobullous lesion or herpetic infection. Cases with discrepant diagnosis on histopathology were reviewed to identify additional cytomorphological features.

Results:

A total of 57 Tzanck smears were performed during the study period. Out of the 18 clinically suspected cases of immunobullous disorders, Tzanck smear findings corroborated the clinical diagnosis in 7/18 cases, one case was diagnosed as cutaneous candidiasis, and diagnosis of immunobullous lesions could be excluded in 5/18 cases. Out of the 19 suspected cases of herpetic infections, viral cytopathic effect was observed in 8/19 cases. Besides immunobullous lesions and herpetic infections, acantholytic cells were also observed in spongiotic dermatitis and genodermatosis. Dyskeratotic keratinocytes seen in vacuolar interface dermatitis were not easily distinguishable from acantholytic cells on Tzanck smear.

Conclusions:

Tzanck smear test is an inexpensive and useful diagnostic tool for certain skin diseases. It can aid in establishing a rapid clinical diagnosis and can serve as a useful adjunct to routine histological examination. We recommend the use of Tzanck smear as a first-line investigation for vesiculobullous, erosive, and pustular lesions.

Comparative study of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test for the diagnosis of pemphigus

BACKGROUND

Pemphigus is one of the potentially fatal autoimmune blistering diseases. An early and accurate diagnosis is important for prognosis and therapy. It may be difficult to diagnosis based on clinical grounds alone. Direct and indirect immunofluorescence, enzyme-linked immunosorbent assay, the Tzanck smear test, or histopathology are all available for the diagnosis of pemphigus. However, there are no generally accepted diagnostic criteria for the diagnosis of this condition at present.

OBJECTIVE

To evaluate the diagnostic value of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test for the diagnosis of pemphigus in dental clinics.

METHODS

A single-center retrospective study was conducted, and the clinical data of 33 patients with pemphigus and 61 controls were collected and analyzed from the Department of Oral Medicine, Peking University School of Stomatology, during 2010-2014. The sensitivities and specificities of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test were calculated and compared in two groups.

RESULTS

Sensitivities for the Tzanck smear test, indirect immunofluorescence, and enzyme-linked immunosorbent assay were 96.7%, 84.8%, and 84.8%, respectively, whereas the specificities of these tests were 60%, 91.8%, and 96.7%, respectively. The serial tests for the Tzanck smear test and enzyme-linked immunosorbent assay showed 82% sensitivity and 98.7% specificity.

CONCLUSIONS

The serial test for the Tzanck smear test and enzyme-linked immunosorbent assay may represent a simple, rapid, and reliable way to definitive diagnosis of pemphigus. It is recommended as a common test for the diagnosis of pemphigus in dental clinics.