Oral manifestations of patients with lupus erythematosus

Immune-mediated oral mucosal pathology: a comprehensive review and update for clinicians. Part I

The oral mucosa can be involved in a wide variety of mucocutaneous conditions that may present primarily in the mouth or affect other cutaneous or mucosal sites. Many of these conditions are immune mediated and typically present as inflammatory mucosal pathology. Patients experiencing such conditions usually seek medical evaluation and treatment due to the associated pain and discomfort and occasionally taste disturbance or dysphagia and the overall deterioration in the oral health-related quality of life. These conditions share some common features and there could be some overlapping in their clinical presentation, which can lead to delays in diagnosis and proper management of patients. Clinicians dealing with such disorders, including dermatologists, need to be aware of the oral manifestations of mucocutaneous conditions, their clinical features, underlying mechanisms, diagnostic approaches, and treatment options, as well as the recent advances in the research on these conditions. This review provides a comprehensive, evidence-based reference for clinicians, with updated insights into a group of immune mediated conditions known to cause oral mucosal pathology. Part one will cover oral lichen planus, erythema multiforme and systemic lupus erythematosus, while part two will cover pemphigus vulgaris and mucous membrane pemphigoid, recurrent aphthous stomatitis, in addition to the less common disorders linear IgA disease, dermatitis herpetiformis and epidermolysis bullosa.

Cytomegalovirus-induced oral ulcers: A case report and literature review

Cytomegalovirus (CMV) ulcerations are rare clinical entities, but their occurrence is favored in immunocompromised patients who present a favorable environment for opportunistic infections. We describe the case of a patient treated for a systemic lupus erythematosus suffering from deep oral ulcerations. The case illustrates the complexity of establishing a precise etiological diagnosis of CMV lesions, as the diagnostic hypothesis can be varied: related to an immunodeficiency disorder or drug-induced toxidermia.

Dental caries and risk of newly-onset systemic lupus erythematosus: a nationwide population-based cohort study

OBJECTIVE

This study investigated whether patients with history of dental caries are associated with an increased risk of newly-onset systemic lupus erythematosus (SLE).

METHODS

A total of 501,461 carious patients and 258,918 controls without carious teeth were enrolled between 1997 and 2013 from the National Health Insurance Research Database. Subgroup analyses were conducted based on restorative materials including amalgam, composite resins, or both. The cumulative incidence and hazard ratios (HRs) of SLE development were derived after adjusting for age, sex, socioeconomic status, income, insured classification, comorbidities, and frequency of dental visit in a multivariable model.

RESULTS

The risk of SLE was significantly higher in carious patients (HR = 1.98, 95% confidence interval [CI] = 1.65-2.38) compared to controls. Dose-dependent relationship between caries and risk of SLE was identified. The risk of SLE was higher among those who had dental visits ≧11 (HR = 2.53, 95% CI = 1.86-3.43), followed by those with 3-10 dental visits (HR = 1.86, 95% CI = 1.36-2.54), when compared to those with 1-2 visits, and was higher among those who had carious teeth extractions ≧5 (HR = 1.88, 95% CI = 1.19-2.97), followed by those with 1-4 carious teeth extractions (HR = 1.36, 95% CI = 1.17-1.59) than those without extraction. The risk of SLE for dental caries management among different restorative materials, including amalgam, composite resins, or both, was not statistically different.

CONCLUSIONS

Patients with dental caries were associated with higher SLE risks. The relationship between dental caries and risk of SLE was dose-dependent, regardless of the material used for the restoration.

Systemic Diseases with Oral Manifestations and Their Impact on Health-Related Quality of Life

Health-related quality of life is a multidimensional concept established to evaluate the physical, psychological, and social impacts of health conditions on individuals’ well-being. Various tools for measuring health-related quality of life can be categorized into two subsets: generic and disease–specific instruments. The oral cavity can be stricken by a broad range of local and systemic diseases and their systemic treatment modalities. The most common systemic illnesses associated with oral lesions are hematologic disorders, endocrinopathies, neurological disorders, gastrointestinal conditions, mucocutaneous and rheumatic diseases, and neoplastic processes. Their manifestations in the oral cavity are, in most cases, rather nonspecific but should not be overlooked. Oral health is one of the most important parts of overall health, thus it has been proposed that poor oral health may affect health–related quality of life. The presence of oral manifestations of systemic diseases has a negative impact on the daily functioning of patients, decreasing their overall well-being. This article will review the most common systemic diseases with oral manifestations and their impact on the health–related quality of life. Oral health researchers should put a stronger emphasis on the patient-reported quality of life as a primary outcome in future clinical trials. The significance of this area has still not been widely understood in the current dental literature even though it could help improve patients’ health-related quality of life.

The prevalence of oral mucosal lesions and related factors in systemic lupus erythematosus patients

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic inflammatory multi systematic disease of unknown aetiology. SLE has a wide range of symptoms. The most common symptoms are joint pain, skin rash and fever. Oral lesions in SLE manifest in a variety of forms, such as oral mucosal ulceration, mouth burns, xerostomia and salivary gland diseases, temporomandibular joint disease, periodontal disease, dysgeusia, white lesions, oedema, bleeding and petechiae.

OBJECTIVE

This study was conducted to evaluate the prevalence of oral mucosal lesions and their related factors in patients with SLE, giving the lack of comprehensive statistical data in Syria and the differences between reported prevalence.

PATIENTS AND METHODS

A cross-sectional study was performed in the Al-Mouassat University Hospital in Damascus. Patients were evaluated appropriating observation, clinical examination, completing questionnaires, studying patient's medical records and paraclinical laboratory tests if required. Four types of oral lesions were evaluated: ulcer, erythema, white plaque and spots. The diagnosis of these lesions was made according to observation and clinical examination, and the location of each lesion was also recorded. Data were analysed using SPSS version 16.0.

RESULT

In this study, 42 (70% %) out of 60 patients (38 women and 4 men) had oral lesions, while 18 (30%) had none. The most common areas for the lesions were the buccal mucosa (26.1%) and the lips (14.2%). Of the 42 patients with oral lesions, 12 (27.6%) showed ulcers. There was a significant relationship between the following factors and oral lesions: oral hygiene status, the duration of the disease involvement, frequency of pregnancies, the amount of daily use of corticosteroids without significant difference between dosage groups, and medications used for SLE treatment other than corticosteroids (p < 0.008) without mentioned names or dosages. Conversely, age, sex, cigarette smoking and medications other than those used for SLE treatment were not significantly related to the presence of oral lesions (p value was greater than 0.05 in all subjects).

Comparative Analyses of Clinical Features, Histopathology, and CD123 Immunohistochemistry of Oral Lupus Erythematosus, Lichen Planus, and Other Lichenoid Lesions

BACKGROUND

Oral lupus erythematosus (OLE) and oral lichen planus (OLP) are among the common causes of oral lichenoid lesions (OLLs). The differential diagnosis among causes of OLLs, particularly between OLE and OLP, is challenging as they have significant clinical and histopathological overlap.

OBJECTIVES

To compare and summarize the clinical, histopathological, and direct immunofluorescence (DIF) findings between OLE, OLP, and other OLLs and to explore the diagnostic value of CD123 immunohistochemistry.

METHODS

A retrospective study on patients with OLE, OLP, and other OLLs was performed between January 2014 and December 2019. The baseline characteristics, the clinical, histopathological, and DIF features, as well as CD123 immunohistochemistry for plasmacytoid dendritic cells (PDCs) were statistically analyzed and compared between groups.

RESULTS

Of 70 patients, 12 had OLE, 39 had OLP, and 19 had other OLLs. Oral erosions/ulcers were the most common findings in all three groups. Red macules, telangiectases, and discoid plaques were more common in OLE patients, while OLP cases were typified by reticulated patches (p < 0.05). Additionally, white patches were found more often in other OLLs than in both OLE and OLP (p = 0.002). Histologically, mucosal atrophy, basal vacuolization, and perivascular infiltrate were observed in OLE, whereas OLP specimens possessed mucosal hyperplasia, hypergranulosis, and compact orthokeratosis (p < 0.05). Mucosal spongiosis was a histologic feature that favored other OLLs over OLE and OLP (p < 0.001). Data on DIF were nonspecific for all three conditions. For immunohistochemical staining, the median number of total CD123+ PDCs was observed to be higher in OLE than OLP in the mucosal-submucosal junction (MSJ) (p = 0.021), the superficial perivascular area (p = 0.026), and the superficial and deep perivascular areas (p = 0.001). Likewise, PDCs in clusters ≥2+ were seen in significantly higher numbers on OLE than OLP along the MSJ (p = 0.002), the superficial perivascular area (p < 0.001), as well as the superficial and deep perivascular areas (p = 0.011). CD123+ PDCs were found to be significantly more numerous in both OLE and OLP than other OLLs in all of the abovementioned areas (all p < 0.05).

CONCLUSION

While there are some differences in the clinicopathological features between OLE, OLP, as well as other OLLs, a significant overlap remains. The quantity and distribution pattern of CD123 immunohistochemical staining has a diagnostic implication in differentiating OLE from OLP and other OLLs.

Exploring the Oral Microbiome in Rheumatic Diseases, State of Art and Future Prospective in Personalized Medicine with an AI Approach

The oral microbiome is receiving growing interest from the scientific community, as the mouth is the gateway for numerous potential etiopathogenetic factors in different diseases. In addition, the progression of niches from the mouth to the gut, defined as "oral-gut microbiome axis", affects several pathologies, as rheumatic diseases. Notably, rheumatic disorders (RDs) are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. In this review, we examine evidence which supports a role for the oral microbiome in the etiology and progression of various RDs, including rheumatoid arthritis (RA), Sjogren's syndrome (SS), and systemic lupus erythematosus (SLE). In addition, we address the most recent studies endorsing the oral microbiome as promising diagnostic biomarkers for RDs. Lastly, we introduce the concepts of artificial intelligence (AI), in particular, machine learning (ML) and their general application for understanding the link between oral microbiota and rheumatic diseases, speculating the application of a possible AI approach-based that can be applied to personalized medicine in the future.

Orofacial manifestations and dental management of systemic lupus erythematosus: A review

Systemic lupus erythematosus (SLE) is an autoimmune multisystem disease with numerous clinical manifestations. There is no consensus about the ideal oral management for this group of patients to date. This review aimed to describe the broad spectrum of orofacial and clinical manifestations and their therapeutic approaches. Studies concerning orofacial manifestations of SLE and dental treatment modalities were selected by a literature search (1978-2019) using Google Scholar, PubMed/MEDLINE electronic databases. The initial search strategy provided a total of 129 articles, and of these, 30 were included for qualitative synthesis. The reviewed studies revealed that SLE patients are more at risk of compromised oral and dental health exhibiting increased risk of periodontal diseases and temporomandibular joint disorders. The use of systemic drugs especially immunosuppressive and anticoagulants in SLE patients may also influence their oral management. Results emphasize the need to carry out, at an early stage of the disease, an appropriate oral management of these patients to improve oral health-related quality of life and to prevent the need of more invasive therapeutics. A multidisciplinary approach is needed for dental and medical management of such patients.

Temporomandibular Disorders and Oral Features in Systemic Lupus Erythematosus Patients: An Observational Study of Symptoms and Signs

Aims: Systemic Lupus Erythematosus (SLE) is a connective tissue disease characterized by a wide range of pleomorphic pictures, including mucocutaneous, renal, musculoskeletal and neurological symptoms. It involves oral tissues, with hyposalivation, tooth decay, gingivitis, angular cheilitis, ulcers and glossitis. Temporomandibular disorders represent a heterogeneous group of inflammatory or degenerative diseases of the stomatognatic system, with algic and/or dysfunctional clinical features involving temporomandibular joint (TMJ) and related masticatory muscles. The aim of this study was to investigate the prevalence of oral manifestations and temporomandibular disorders (TMD) in SLE patients (Lp) compared with a control group. Methods: Fifty-five patients (9 men and 46 women) with diagnosed Lupus were recruited in the study group. A randomly selected group of 55 patients, matched by sex and age, served as control group. The examination for TMD symptoms and signs was based on the standardized Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) through a questionnaire and clinical examination. Results: Lupus patients complained more frequently (95.8%) of oral and TMJ symptoms (dysgeusia, stomatodynia, masticatory muscle pain during function, neck and shoulder muscles pain and presence of tinnitus) but only xerostomia (χ2=4,1548 p=0,0415), temple headache (χ2=4,4542 p=0,035) and the sensation of a stuck jaw (Mid-p-test p=0,043) were significant. About signs, cheilitis (p=0,0284) oral ulcers (χ2=4,0104 p=0,045) and fissured tongue are significantly more frequent in study group. The salivary flow was significantly decreased in the study group respect to the control one (p<0.0001). As regard to the oral kinematics, restricted movements (RM) in protrusion and left lateral movement were significantly different between study group and controls. In particular, 85,2% of Lp showed limited protrusion versus 56,4% of controls (χ2= 10,91 p<0,001); 59,3% of Lp had also a limitation during left lateral movement versus 47,3% of controls (T=2,225 p=0,0282). About bruxism, only the indentations on the lateral edges of the tongue were found in Lp group (72,7%), with a significant difference respect to controls (χ2=7,37 p=0,007). Conclusions: While masticatory muscles have an overlapping behavior in both groups, the findings collected show a more severe TMJ kinematic impairment in Lp than in controls, with protrusion and left lateral movements significantly different. In addition, a remarkable reduction of salivary flow has been detected in Lp compared to controls. In conclusion, this autoimmune disease seems to play a role in oral manifestations and TMJ disorders, causing an increase in orofacial pain and an altered chewing function.

Oral Ulcers in Juvenile-Onset Systemic Lupus Erythematosus: A Review of the Literature

Oral ulcers are the most common mucosal sign in juvenile-onset systemic lupus erythematosus (JSLE). The ulcers are one of the key clinical features; however, the terminology of oral ulcers, especially in JSLE patients, is often vague and ill-defined. In fact, there are several clinical manifestations of oral ulcers in JSLE, and some lesions occur when the disease is active, indicating that early management of the disease should be started. Oral ulcers are classified as lupus erythematosus (LE) specific, where the lesional biopsy shows a unique pattern of mucosal change in LE, and LE nonspecific, where the ulcers and their histopathological findings can be found in other oral diseases. Here, the clinical manifestations, diagnosis and management of oral ulcers in JSLE patients are reviewed.

Oral lichenoid lesions: distinguishing the benign from the deadly

Oral lichen planus is a chronic inflammatory disease of unknown etiology or pathogenesis with varied disease severity that waxes and wanes over a long period of time. Although a common oral mucosal disease, accurate diagnosis is often challenging due to the overlapping clinical and histopathological features of oral lichen planus and other mucosal diseases. Other immune-mediated mucocutaneous diseases can exhibit lichenoid features including mucous membrane pemphigoid, chronic graft-versus-host disease, and discoid lupus erythematosus. Reactive changes to dental materials or to systemic medications can mimic oral lichen planus both clinically and histologically. In these situations the clinical presentation can be useful, as oral lichen planus presents as a multifocal process and is usually symmetrical and bilateral. Dysplasia of the oral cavity can exhibit a lichenoid histology, which may mask the potentially premalignant features. Proliferative verrucous leukoplakia, an unusual clinical disease, can often mimic oral lichen planus clinically, requiring careful correlation of the clinical and pathologic features.

The autoimmunity-oral microbiome connection

To date, there is a major effort in deciphering the role of complex microbial communities, especially the oral and gut microbiomes, in the pathogenesis of various diseases. Increasing evidence indicates a key role for the oral microbiome in autoimmune diseases. In this review article, we discuss links of the oral microbiota to a group of autoimmune diseases, that is, Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), Crohn's disease (CD), and rheumatoid arthritis (RA). We particularly focus on factors that affect the balance between the immune system and the composition of microbiota leading to dysbiosis, loss of tolerance and subsequent autoimmune disease progression and maintenance.

Orofacial manifestations in patients with inflammatory rheumatic diseases

The main orofacial manifestation of the inflammatory rheumatic diseases is that of Sjögren's syndrome. In addition, there is a constellation of orofacial manifestations of the inflammatory rheumatic diseases, many of which are extra-articular with some constituting presenting signs of the underlying rheumatic disease. This review will discuss the orofacial manifestations in a variety of connective tissue diseases and will also allude to the oral adverse drug reactions that may occur as a consequence of therapy.

What rheumatologists should know about orofacial manifestations of autoimmune rheumatic diseases

Orofacial manifestations occur frequently in rheumatic diseases and usually represent early signs of disease or of its activity that are still neglected in clinical practice. Among the autoimmune rheumatic diseases with potential for oral manifestations, rheumatoid arthritis (RA), inflammatory myopathies (IM), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), relapsing polychondritis (RP) and Sjögren's syndrome (SS) can be cited. Signs and symptoms such as oral hyposalivation, xerostomia, temporomandibular joint disorders, lesions of the oral mucosa, periodontal disease, dysphagia, and dysphonia may be the first expression of these rheumatic diseases. This article reviews the main orofacial manifestations of rheumatic diseases that may be of interest to the rheumatologist for diagnosis and monitoring of autoimmune rheumatic diseases.

Diagnosis of oral lichen planus: a position paper of the American Academy of Oral and Maxillofacial Pathology

Despite being one of the most common oral mucosal diseases and recognized as early as 1866, oral lichen planus (OLP) is still a disease without a clear etiology or pathogenesis, and with uncertain premalignant potential. More research is urgently needed; however, the research material must be based on an accurate diagnosis. Accurate identification of OLP is often challenging, mandating inclusion of clinico-pathological correlation in the diagnostic process. This article summarizes current knowledge regarding OLP, discusses the challenges of making an accurate diagnosis, and proposes a new set of diagnostic criteria upon which to base future research studies. A checklist is also recommended for clinicians to provide specific information to pathologists when submitting biopsy material. The diagnostic process of OLP requires continued clinical follow-up after initial biopsy, because OLP mimics can manifest, necessitating an additional biopsy for direct immunofluorescence study and/or histopathological evaluation in order to reach a final diagnosis.

What rheumatologists should know about orofacial manifestations of autoimmune rheumatic diseases

Orofacial manifestations occur frequently in rheumatic diseases and usually represent early signs of disease or of its activity that are still neglected in clinical practice. Among the autoimmune rheumatic diseases with potential for oral manifestations, rheumatoid arthritis (RA), inflammatory myopathies (IM), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), relapsing polychondritis (RP) and Sjögren's syndrome (SS) can be cited. Signs and symptoms such as oral hyposalivation, xerostomia, temporomandibular joint disorders, lesions of the oral mucosa, periodontal disease, dysphagia, and dysphonia may be the first expression of these rheumatic diseases. This article reviews the main orofacial manifestations of rheumatic diseases that may be of interest to the rheumatologist for diagnosis and monitoring of autoimmune rheumatic diseases.

Prevalence of hyposalivation in patients with systemic lupus erythematosus in a brazilian subpopulation

Background. Systemic lupus erythematosus (SLE) is a chronic inflammatory, multisystem, and autoimmune disease. Objective. The aim of this study was to describe the prevalence of hyposalivation in SLE patients and evaluate factors associated. Methods. This is a cross-sectional study developed at the Cuiaba University General Hospital (UNIC-HGU), Mato Grosso, Brazil. The study population consisted of female SLE patients treated at this hospital from 06/2010 to 12/2012. Unstimulated salivary flow rates (SFRs) were measured. Descriptive and inferential analyses were performed in all cases using a significance level P < 0.05. Results. The results showed that 79% of patients with systemic lupus erythematosus suffered from hyposalivation and that the disease activity and age in years were the factors that resulted in statistically significant differences. Conclusion. The activity of the disease, age >27 years, and the drugs used were factors associated with hyposalivation, resulting in a statistically significant decrease in saliva production.

Systemic lupus erythematosus: epidemiology, pathophysiology, manifestations, and management

Systemic lupus erythematosus is a chronic autoimmune disorder characterized by production of autoantibodies directed against nuclear and cytoplasmic antigens, affecting several organs. Although cause is largely unknown, pathophysiology is attributed to several factors. Clinically, this disorder is characterized by periods of remission and relapse and may present with various constitutional and organ-specific symptoms. Diagnosis is achieved via clinical findings and laboratory examinations. Therapies are based on disease activity and severity. General treatment considerations include sun protection, diet and nutrition, smoking cessation, exercise, and appropriate immunization, whereas organ-specific treatments include use of steroidal and nonsteroidal anti-inflammatory drugs, immunosuppressive agents, and biologic agents.

The prevalence of oral mucosal lesions and related factors in 188 patients with systemic lupus erythematosus

Background: One of the most important concerns about systemic lupus erythematosus (SLE) is the presence of oral lesions, which in turn is one of the diagnostic criteria for SLE. Regarding the wide range of oral lesions and the absence of comprehensive data in Iran, this study aimed to evaluate the prevalence of oral mucosal lesions and related factors in patients with SLE at three rheumatology clinics in Tehran. Methods: This descriptive study was performed on 188 patients by observation, clinical examination, completing questionnaire and also evaluating patients’ medical records. The lesions explored were ulcer, erythema, erythematous center with white striae or spots, and white plaques. Related factors taken into consideration were age, sex, smoking, frequency of pregnancy, oral health status, duration of disease, medications taken daily dosage of corticosteroid drugs, and the state of disease control. Sampling was done by the continuous method and data obtained were analyzed by SPSS version 16.0 and ordinal regression tests. Findings: Out of 188 patients, 102 (54.3%) patients had oral mucosal lesions. The most prevalent lesion was ulcer (28.1%) and the most common region involved was the buccal and labial mucosa. Conclusion: With regard to the high prevalence of oral mucosal lesions in patients with SLE, it is of paramount importance to emphasize early detection of these lesions as a mean of diagnosis of disease and faster initiation of treatment.

Autoimmune disease and subsequent risk of developing alimentary tract cancers among 4.5 million US male veterans

BACKGROUND

Autoimmunity is clearly linked with hematologic malignancies, but less is known about autoimmunity and alimentary tract cancer risk, despite the specific targeting of alimentary organs and tissues by several autoimmune diseases. The authors therefore conducted the first systematic evaluation of a broad range of specific autoimmune diseases and risk for subsequent alimentary tract cancer.

METHODS

On the basis of 4,501,578 US male veterans, the authors identified 96,277 men who developed alimentary tract cancer during up to 26.2 years of follow-up. By using Poisson regression methods, the authors calculated relative risks (RRs) and 95% confidence intervals.

RESULTS

A history of autoimmune disease with localized alimentary tract effects generally increased cancer risks in the organ(s) affected by the autoimmune disease, such as primary biliary cirrhosis and liver cancer (RR, 6.01; 95% confidence interval [CI], 4.76-7.57); pernicious anemia and stomach cancer (RR, 3.17; 95% CI, 2.47-4.07); and ulcerative colitis and small intestine, colon, and rectal cancers (RR, 2.53; 95% CI, 1.05-6.11; RR, 2.06; 95% CI, 1.70-2.48; and RR, 2.07; 95% CI, 1.62-2.64, respectively). In addition, a history of celiac disease, reactive arthritis (Reiter disease), and systemic sclerosis all were associated significantly with increased risk of esophageal cancer (RR, 1.86-2.86). Autoimmune diseases without localized alimentary tract effects generally were not associated with alimentary tract cancer risk, with the exception of decreased risk for multiple alimentary tract cancers associated with a history of multiple sclerosis.

CONCLUSIONS

These findings support the importance of localized inflammation in alimentary tract carcinogenesis. Future research is needed to confirm the findings and improve understanding of underlying mechanisms by which autoimmune diseases contribute to alimentary tract carcinogenesis.

Update on the treatment of systemic lupus erythematosus

The improving prognosis in patients with systemic lupus erythematosus is due in no small part to refinements in treatment. One idea is to tailor the treatment to the specific clinical features. For example, the treatment of cutaneous lupus may require antimalarial and topical agents initially, with more severe cases requiring dapsone or even thalidomide. Conversely, renal involvement in systemic lupus erythematosus is better treated with corticosteroids and immunosuppressive agents such as intravenous cyclophosphamide, mycophenolate mofetil or azathioprine. It is very clear that comorbidities such as steroid-induced diabetes mellitus, hypertension and osteonecrosis have been responsible for a great deal of the morbidity associated with systemic lupus erythematosus and must be aggressively managed. In addition to 'traditional' agents, newer medications such as rituximab, abatacept and B-lymphocyte stimulator antagonists are showing great promise and will probably be an an important part of the management of severe lupus in the future.

Kutaner Lupus erythematodes

Cutaneous lupus erythematosus (CLE) is a heterogenous disorder with a wide range of skin manifestations. Therefore, it has been difficult to develop a unifying concept for classifying CLE from the dermatologic perspective in the past. In 2004, the classification system was updated and includes now acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), and intermittent CLE (ICLE). Additional rarely described variants are not listed as separate entities but are included in the classical forms. Diagnosis of the different subtypes of CLE is made by considering genetic, clinical, histopathologic, and immunoserologic findings, with a systematic analysis of individual criteria. In the past years, the etiology and pathogenesis of CLE has been subject of intensive research and it has been shown by several groups that exogenous factors, such as ultraviolet light and drugs, can induce CLE. The first part of this review will enable the reader to identify the various clinical manifestations of CLE and to employ characteristic criteria to assess differential diagnostic considerations.