[Notions of epidemiology of value in dermatology]. / Notions d'épidémiologie utiles en dermatologie.

Epidemiology, which was initially confined to the distribution of diseases in populations (descriptive epidemiology) and the factors responsible for such distribution (analytical epidemiology), also involves the evaluation of diagnostic and therapeutic strategies, as well as prognostic factors. Epidemiology provides elements that form the basis for medical and public health decisions. Information is collected from systematic records, which include large databases, or through specific surveys. Descriptive studies utilise mortality rates, as well as incidence and prevalence figures. The aim of aetiological epidemiology is to demonstrate a causal relationship between exposure and disease. It is necessary to check that studies do not present any major bias and to seek evidence in favour of causality. The strength of a causal relationship is calculated using relative risk or odds ratio. Other measurements of risk include attributable risk and aetiological fraction. Screening and diagnostic strategies are evaluated using the concepts of sensitivity, specificity, and above all, levels of likelihood that help determine the probability of a given patient becoming ill as a result of his or her personal characteristics and of test results. Evaluation of prognostic factors enables scores to be constructed allowing the probability of a given clinical outcome to be calculated as a function of patient characteristics.

Colorectal cancer (CRC) monitoring by 6-monthly 18FDG-PET/CT: an open-label multicentre randomised trial.

Background: [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18FDG-PET/CT) has high sensitivity for detecting recurrences of colorectal cancer (CRC). Our objective was to determine whether adding routine 6-monthly 18FDG-PET/CT to our usual monitoring strategy improved patient outcomes and to assess the effect on costs. Patients and methods: In this open-label multicentre trial, patients in remission of CRC (stage II perforated, stage III, or stage IV) after curative surgery were randomly assigned (1 : 1) to usual monitoring alone (3-monthly physical and tumour marker assays, 6-monthly liver ultrasound and chest radiograph, and 6-monthly whole-body computed tomography) or with 6-monthly 18FDG-PET/CT, for 3 years. A multidisciplinary committee reviewed each patient's data every 3 months and classified the recurrence status as yes/no/doubtful. Recurrences were treated with curative surgery alone if feasible and with chemotherapy otherwise. The primary end point was treatment failure defined as unresectable recurrence or death. Relative risks were estimated, and survival was analysed using the Kaplan-Meier method, log-rank test, and Cox models. Direct costs were compared. Results: Of the 239 enrolled patients, 120 were in the intervention arm and 119 in the control arm. The failure rate was 29.2% (31 unresectable recurrences and 4 deaths) in the intervention group and 23.7% (27 unresectable recurrences and 1 death) in the control group (relative risk = 1.23; 95% confidence interval, 0.80-1.88; P = 0.34). The multivariate analysis also showed no significant difference (hazards ratio, 1.33; 95% confidence interval, 0.8-2.19; P = 0.27). Median time to diagnosis of unresectable recurrence (months) was significantly shorter in the intervention group [7 (3-20) versus 14.3 (7.3-27), P = 0.016]. Mean cost/patient was higher in the intervention group (18 192 ± 27 679 € versus 11 131 ± 13 €, P < 0.033). Conclusion: 18FDG-PET/CT, when added every 6 months, increased costs without decreasing treatment failure rates in patients in remission of CRC. The control group had very close follow-up, and any additional improvement (if present) would be small and hard to detect. ClinicalTrials.gov identifier: NCT00624260.

Frequency and prognostic value of cutaneous molecular residual disease in mycosis fungoides: a prospective multicentre trial of the Cutaneous Lymphoma French Study Group.

BACKGROUND: Monoclonal T-cell receptor (TCR) rearrangement is detected in 57-75% of early-stage mycosis fungoides (MF) at diagnosis. A retrospective study showed molecular residual disease (MRD) in 31% of patients in complete clinical remission (CR) after 1 year of treatment. OBJECTIVES: To confirm the frequency of MRD at 1 year and to determine its prognostic value for further relapse. METHODS: Patients with T1-, T2- or T4-stage MF were prospectively included in this multicentre study. At diagnosis, clinical lesions and healthy skin were biopsied. After 1 year of topical treatment, previously involved skin of patients in CR was biopsied for histology and analysis of TCR-γ gene rearrangement. The results were compared with the clinical status each year for 4 years. RESULTS: We included 214 patients, 133 at T1, 78 at T2 and three at T4 stage. At diagnosis, 126 of 204 cases (61·8%) showed TCR clonality in lesional skin. After 1 year, 83 of 178 patients (46·6%) still being followed up were in CR and 13 of 63 (21%) showed MRD. At 4 years, 55 of 109 patients (50·5%) still being followed up were in CR and 44 of 109 (40·4%) were in T1 stage. MRD did not affect clinical status at 4 years (CR vs. T1/T2, P = 1·0; positive predictive value 36·4%; negative predictive value 67·6%). CONCLUSIONS: T-cell clonality at diagnosis and MRD at 1 year are not prognostic factors of clinical status at 4 years.

Histopathology of drug rash with eosinophilia and systemic symptoms syndrome: a morphological and phenotypical study.

BACKGROUND: The histopathological features of drug rash with eosinophilia and systemic symptoms (DRESS) syndrome remain poorly characterized. OBJECTIVES: To better characterize the histopathological features of DRESS syndrome, and define the phenotype of the effector cells in the skin and compare it with maculopapular rash (MPR). METHODS: We conducted a retrospective study on 50 skin biopsies from patients with DRESS syndrome (n = 36). Histopathological and immunophenotypical features were studied and compared with a series of MPRs (n = 20). RESULTS: Foci of interface dermatitis, involving cutaneous adnexae, were frequently seen in cases of DRESS. Eosinophils were seen in only 20% of cases and neutrophils in 42%. Eczematous (40%), interface dermatitis (74%), acute generalized exanthematic pustulosis-like (20%) and erythema multiforme-like (24%) patterns were observed. The association of two or three of these patterns in a single biopsy was significantly more frequent in cases of DRESS than in a series of nondrug-induced dermatoses (P < 0.01), and appeared to be more marked in DRESS syndrome with severe cutaneous lesions (P = 0.01) than in less severe cases of DRESS and MPR. A higher proportion of CD8(+) and granzyme B(+) lymphocytes was observed in cases of DRESS with severe cutaneous eruptions (erythroderma and/or bullae). Atypical lymphocytes were found in 28% of biopsies, and expressed CD8 in most cases; a cutaneous T-cell clone was rarely found (6%). CONCLUSIONS: The histopathology of DRESS syndrome highlights various associated inflammatory patterns in a single biopsy. Cutaneous effector lymphocytes comprise a high proportion of polyclonal CD8(+) granzyme B(+) T lymphocytes.

Geriatric syndromes increased the nutritional risk in elderly cancer patients independently from tumour site and metastatic status. The ELCAPA-05 cohort study.

BACKGROUND & AIMS: We assessed the prevalence and risk factors of malnutrition in elderly cancer patients. METHODS: We studied a prospective cohort of solid cancer patients aged ≥70 years at referral to two geriatric oncology clinics between 2007 and 2010. Nutrition was evaluated using the Mini-Nutritional Assessment (MNA) using validated cut-offs (<17: malnutrition, 17-23.5: at-risk for malnutrition). Patients with non-digestive tumours (breast, prostate, urinary tract) and with digestive (colorectal, upper digestive tract and liver) were analysed separately using multinomial logistic regression. RESULTS: Of 643 consecutive patients, 519 had available data (median age, 80; men, 48.2%; metastases, 46.3%; digestive cancer 47.8%). In non-digestive group, 13.3% had malnutrition versus 28.6% in digestive group. The link between metastasis and malnutrition was significantly higher in non-digestive group (adjusted odds ratio [ORa ], 25.25; 95%CI: 5.97-106.8) than in digestive group (ORa, 2.59; 1.08-6.24; p for heterogeneity = 0.04). Other factors independently associated with malnutrition were cognitive impairment (ORa MMMSE ≤ 24 versus > 24 in non-digestive group: 16.68; 4.89-56.90 and in digestive group: 3.93; 1.34-11.50), and depressed mood (ORa MiniGDS ≥1 versus <1 in non-digestive group: 11.11; 3.32-37.17 and in digestive group: 3.25; 1.29-8.15) and fall risk (ORa fall risk versus no fall risk in non-digestive group: 4.68; 1.77-12.37; in digestive group: 100% of malnourished patients were faller's). CONCLUSION: We highlighted, in elderly cancer patients, the high prevalence of malnutrition and that geriatrics syndromes (i.e. cognitive impairment, depressed mood and fall risk) were independent risk factors for malnutrition. Moreover, metastatic status was significantly much more strongly associated with malnutrition in non-digestive than digestive tumours.

Colorectal cancer screening: factors associated with colonoscopy after a positive faecal occult blood test.

BACKGROUND: Contextual socio-economic factors, health-care access, and general practitioner (GP) involvement may influence colonoscopy uptake and its timing after positive faecal occult blood testing (FOBT). Our objectives were to identify predictors of delayed or no colonoscopy and to assess the role for GPs in colonoscopy uptake. METHODS: We included all residents of a French district with positive FOBTs (n = 2369) during one of the two screening rounds (2007-2010). Multilevel logistic regression analysis was performed to identify individual and area-level predictors of delayed colonoscopy, no colonoscopy, and no information on colonoscopy. RESULTS: A total of 998 (45.2%) individuals underwent early, 989 (44.8%) delayed, and 102 (4.6%) no colonoscopy; no information was available for 119 (5.4%) individuals. Delayed colonoscopy was independently associated with first FOBT (odds ratio, (OR)), 1.61; 95% confidence interval ((95% CI), 1.16-2.25); and no colonoscopy and no information with first FOBT (OR, 2.01; 95% CI, 1.02-3.97), FOBT kit not received from the GP (OR, 2.29; 95% CI, 1.67-3.14), and socio-economically deprived area (OR, 3.17; 95% CI, 1.98-5.08). Colonoscopy uptake varied significantly across GPs (P=0.01). CONCLUSION: Socio-economic factors, GP-related factors, and history of previous FOBT influenced colonoscopy uptake after a positive FOBT. Interventions should target GPs and individuals performing their first screening FOBT and/or living in socio-economically deprived areas.

Neurofibromatosis 1 phenotype associated to malignant peripheral nerve sheath tumours: a case-control study.

BACKGROUND: Malignant peripheral nerve sheath tumours (MPNSTs) are the main cause of death in neurofibromatosis 1 adult patients. OBJECTIVES: To determine the clinical type of neurofibromas associated to MPNSTs. METHODS: Case-control study. Cases were neurofibromatosis 1 adults with MPNSTs and controls were patients without MPNSTs individually matched by age and sex (1 : 3). Both were recruited from our database. The following variables were studied: clinical presence of cutaneous, subcutaneous or plexiform neurofibromas and of internal neurofibromas. Internal neurofibromas were confirmed by clinical imaging. Multivariate odds ratios (aORs) were estimated with their 95% confidence interval (CI). RESULTS: From January 1995 to December 2007, 52 patients (cases) were identified with a MPNSTs, 155 controls could be recruited. In the multivariate analysis, MPNSTs were significantly associated with the presence of internal NFs (aOR: 7.5; 95% CI: 3.2-17.4), a trend for an association was observed for the presence of subcutaneous neurofibromas (aOR: 2.11; 95% CI: 0.89-5). CONCLUSIONS: This study confirms the association between the MPNSTs and the internal neurofibromas. The later are indeed associated with a high risk of malignant transformation.

[Day-care hospitalisation in the dermatology departments of French university hospitals]. / Organisation et activité des hôpitaux de jour des services de dermatologie des CHU en France : étude transversale prospective.

BACKGROUND: Day hospital is a unit allowing the provision of several services together in a single day such as complex or specific therapy, or investigations requiring the services of different technical departments. This paper describes the structure and activity of dermatological day hospitals within French university hospitals (CHU). PATIENTS AND METHODS: A transverse prospective study was performed over a 2-week period in 2009 based on a first questionnaire which assessed the organisation and structure of the day hospitals (one questionnaire per day hospital unit), while the second assessed the activity of the day hospitals (one questionnaire for each patient attending day hospitals) throughout the period covered by the survey. RESULTS: Twenty-eight of the 44 dermatology French university hospital day centres responded to the survey (participation rate: 63 %). Six had access to shared day hospital facilities while the 22 others had dedicated dermatology facilities. The day hospital unit was part of a national reference centre in 13 of 24 cases. The median number of beds per day-hospital structure was six for a median of eight patients admitted per day and 1500 sessions recorded each year. On average, the teams comprised two full-time doctors, two nurses, 1.25 hospital workers and one secretary. The mean number of administrative documents generated per unit each week was 57. There were 793 admissions to day hospitals throughout the survey period, for examinations in 61 % of cases and for treatment in 37 % of cases. Fifteen percent of patients were seen without prior arrangement for a variety of intercurrent events. The mean amount of doctor's time devoted to each patient was 25 min. Among the main diseases seen at dermatology day hospitals, we noted cancer (44 % of admissions, 322 cases), psoriasis (7 % of admissions, 54 cases) and chronic wounds (5 % of admissions, 43 cases). DISCUSSION: Dermatology day hospitals serve to provide treatment for complex or costly diseases requiring a variety of specialised laboratory examinations in a single unit all at one time. A considerable workload is generated, particularly in medical and administrative terms. These are well-adapted structures with their own staff, a selection of technical means and upstream scheduling allowing multidisciplinary patient management. Day hospitals meet a real need in dermatology.

Evolving pattern with age of cutaneous signs in neurofibromatosis type 1: a cross-sectional study of 728 patients.

BACKGROUND: Neurofibromatosis type 1 is fully penetrant by the age of 8 years, and 3 criteria of diagnosis are dermatological: café-au-lait spots (CLS), intertriginous freckling and neurofibromas (NF). OBJECTIVES: The aim of our study was to determine the evolving pattern of cutaneous manifestations during adulthood. METHODS: Phenotypic data of patients seen in our center between March 2003 and December 2009 were studied. Patients were classified in 10-year groups. Following clinical characteristics, the number of CLS and the number of cutaneous and subcutaneous NF were compared according to age. RESULTS: 728 subjects, 404 females and 324 males (mean age of 32.4 years, range 6-80 years) were studied. Four hundred eighty-nine patients were over 20 years old (67%). The number of CLS (small or large) was significantly decreased with age while the number of cutaneous and subcutaneous NF was strongly increased (p < 0.001). CONCLUSIONS: The decrease in CLS with age has not been previously reported while an increase in the number of NF is well described during puberty and pregnancy and with age.

Shrinkage of skin excision specimens: formalin fixation is not the culprit.

BACKGROUND: Discrepancies between cutaneous specimen sizes reported by the dermatosurgeon and the pathologist are important to evaluate because of their legal implications for malignant tumours and the downcoding of surgical acts. OBJECTIVES: The objective of this study was to determine the magnitude of changes in size and the factors influencing the retraction of routine skin excision specimens. METHODS: Three measurements of 82 skin excision specimens--consisting of length and width of the planned surgical excision (in vivo), length, width and depth of the specimens following excision (ex vivo) and of the specimens after formalin fixation (in vitro)--were performed and compared using a nonparametric paired test. Factors (age, sex, type and location of the lesions and initial measures) that could influence the amount of shrinkage were analysed using multiple linear regression models. RESULTS: The mean in vivo to in vitro shrinkage was 16% for length and 18% for width (P<0.001). The shrinkage was significant between in vivo and ex vivo measures (P<0.001), while no difference was observed between ex vivo to in vitro measures. In multivariate analysis, length shrinkage increased significantly with initial length (regression coefficient of 0.24, P=0.001) and limb location (1.25, P=0.048), and decreased significantly with initial width (-0.19, P=0.016). After adjusting for initial width, width shrinkage was neither significantly associated with type of lesion (malignant or not, P=0.20), nor with location (P=0.35). CONCLUSIONS: Shrinkage of skin excision specimens occurred immediately after surgical excision and prior to formalin fixation. Patients' age, sex and type of skin lesion did not influence the amount of shrinkage. Length shrinkage was more important for specimens excised from the extremities and increased with initial length and smaller width.

Correlation between galactomannan antigen levels in serum and neutrophil counts in haematological patients with invasive aspergillosis.

The detection of circulating galactomannan (GM) in serum samples is an important step in the diagnosis of invasive aspergillosis (IA). The assay has been mainly explored in neutropenic patients, and is now used to monitor patients at high risk for IA. However, the performance of the assay varies greatly among studies. The objective of this study was to explore the impact of the neutrophil count on the GM serum index at the time of IA diagnosis. Ninety-nine episodes of proven or probable, microbiologically documented IA in 91 patients with haematological malignancies were studied retrospectively. Three groups were identified: groups 1-3, with <100 polymorphonuclear neutrophils (PMN)/mm(3) (n = 18), between 100 and 500 PMN/mm(3) (n = 21), or >500 PMN/mm(3) (n = 60), respectively. The mean GM index was significantly higher in group 1 than in the other groups (p <0.05). This finding did not change after stratifying the analysis with regard to the use of antibiotics likely to give false-positive GM results or with regard to treatment effective against fungi before the diagnosis of IA. This finding could be considered in the routine use of the GM antigenaemia test in non-neutropenic patients; a negative result or a low GM index should not eliminate the diagnosis of IA. This limitation calls for other microbiological tests, including analysis of bronchoalveolar lavage fluid, to establish a definitive diagnosis of IA.

Psoriasis in France and associated risk factors: results of a case-control study based on a large community survey.

BACKGROUND: Risk factors for psoriasis have been identified. OBJECTIVE: To precisely define these associated factors. METHODS: A survey was conducted using a questionnaire on a representative sample of the French population. A case-control study was conducted. Cases were persons who declared having had psoriasis during the previous 12 months. For each case, 3 matched controls were selected. Cases and controls were compared using univariate and multivariate analyses. RESULTS: The questionnaire was filled out and returned by 6,887 (68.9%) of 10,000 subjects aged 15 years and over; 356 cases were identified. In multivariate analysis, a higher body mass index, current and former smoking habits and beta-blocker intake were independently associated with a higher risk of psoriasis; intake of statins was associated with a decreased risk (p < 0.05). CONCLUSIONS: We confirmed the association of overweight, smoking habits and beta-blocker intake with psoriasis and reported a decreased risk associated with statin intake.

Impact of neurofibromatosis 1 upon quality of life in childhood: a cross-sectional study of 79 cases.

BACKGROUND: Neurofibromatosis 1 (NF1) has a significant impact on quality of life (QoL). OBJECTIVES: To evaluate QoL in NF1 according to phenotype from the viewpoint of children and proxy. METHODS: One hundred and forty families with a child aged between 8 and 16 years, seen consecutively at the National Academic Paediatric Referral Centre for NF1 for a phenotype evaluation, were contacted by mail. Families agreeing to participate were sent two questionnaires, the DISABKIDS for children and proxy and the cartoon version of the Children's Dermatology Life Quality Index (CDLQI). QoL scores were compared with those in other major diseases and were analysed according to age, gender and phenotype. RESULTS: Eighty families agreed to participate, and 79 returned the questionnaires. Using DISABKIDS, NF1 had a higher impact on health-related QoL than asthma (mean+/-SD 75.18+/-18.22 vs. 79.78+/-13.41; P=0.005). The total score was more altered when assessed by proxy than by children (71.20+/-17.94 vs. 75.18+/-18.22; P=0.002). Orthopaedic manifestations, learning disabilities and presence of at least two plexiform neurofibromas were independently associated with a higher impact (P<0.01). The CDLQI score was slightly altered (11.3%). Dermatological signs, such as café-au-lait spots and freckling, did not have a significant impact. CONCLUSIONS: Orthopaedic manifestations, learning disabilities and plexiform neurofibromas are the main complications impacting on QoL during childhood NF1. QoL could be considered as an endpoint for intervention studies in this context.

High prevalence of Foxp3 and IL17 in MMR-proficient colorectal carcinomas.

BACKGROUND AND AIMS: Colorectal cancer (CRC) harbours different types of DNA alterations, including microsatellite instability (MSI). Cancers with high levels of MSI (MSI-H) are considered to have a good prognosis, probably related to lymphocyte infiltration within tumours. The aim of the present study was to characterise the intratumoural expression of markers associated with the antitumour immune response in mismatch repair (MMR)-proficient (MSS) colon cancers. METHODS: Ninety human colon cancers (T) and autologous normal colon mucosa (NT) were quantified for the expression of 15 markers of the immune response with quantitiative reverse transcription-PCR (qRT-PCR). mRNA expression levels were correlated with MMR status. Immunohistochemistry (IHC) was performed using both interleukin 17 (IL17) and CD3 antibodies. RESULTS: Expression of cytotoxic markers (FasL, granzyme B and perforin), inflammatory cytokines (IL1beta, IL6, IL8, IL17 and transforming growth factor beta (TGFbeta)) and a marker of regulatory T cells (forkhead box P3 (Foxp3)) was significantly higher in tumours than in autologous normal tissues. Adjusting for MMR status, higher tumoural expression of both granzyme B and perforin was associated with the MSI-H phenotype, and the perforin T/NT ratio was higher in MSI-H tissues than in MSS tissues. Higher tumoural expression of Foxp3, IL17, IL1beta, IL6 and TGFbeta was associated with the MSS phenotype, and the IL17 T/NT ratio was higher in MSS tissues than in MSI-H tissues as assessed by both qRT-PCR and IHC. CONCLUSIONS: Immune gene expression profiling in CRC displayed different patterns according to MMR status. Higher Foxp3, IL6, TGFbeta and IL17 expression is a particular determinant in MMR-proficient CRC. These may be potential biomarkers for a new prognostic "test set" in sporadic CRCs.

[Requests for emergency appointments with dermatologists in private practice in France: the ETude Urgences en DErmatologie libérale (ET.U.DE) study]. / Demandes de rendez-vous en urgence en dermatologie libérale: ETude Urgences en DErmatologie libérale (ET.U.DE).

BACKGROUND: Requests for emergency appointments are fairly common in private dermatologic practice in France. To our knowledge the frequency and reasons for such requests have not yet been evaluated. The primary objective of our study was to provide a quantitative and qualitative evaluation of such requests and to assess the underlying reasons. The secondary aim was to investigate for an association between emergency requests where response was justified within 48 hours and the symptoms reported by patients in order to establish a predictive score for the validity of requests. METHODS: The study took place during one week in April 2004. Forty French dermatologists took part on a voluntary basis. They deliberately reduced their ongoing schedule to accommodate patients seeking an urgent appointment. We collected data regarding the normal professional activity of each dermatologist, reasons for appointments, symptoms, diagnosis and evaluation of the degree of emergency by the attending dermatologist. Univariate and multivariate analyses were performed and a score was attributed based on the results for the variables used in the logistic regression model. RESULTS: The mean number of patients seen at emergency appointments during the study week doubled in comparison with a normal period. During the week, 613 patients phoned and all questionnaires were completed for 538 (88%) patients. The most common reasons for requesting an appointment were: rash, eczema, pruritus, tumour modification, localized lesion and allergy. The most frequent diagnoses were: eczema, bacterial and viral infection, atopic dermatitis, mycosis and naevus. The dermatologists considered that the consultations were justified within 48 hours for one third of patients. In the multivariate analysis, factors significantly associated with a justified request were of a general medical rather than a dermatological nature: enlarged cysts, blisters, insomnia, impaired activity, onset or aggravation within the previous 7 days, inability to work. The score showed good specificity but poor sensitivity and discriminative value. DISCUSSION: These results suggest that requests for emergency appointments are more frequent than previously suspected (14% of all requests). Physicians considered that emergency appointments within 48 hours were justified for one third of patients. The reasons for consultation and the resulting diagnoses were similar to those seen in emergency hospital consultations. The criteria on which the need for emergency consultation was based were not for the most part dermatologic. The scoring system we established was not sensitive enough to allow reliable pre-selection of patients requiring emergency consultation by telephone.

Multiple large solar lentigos on the upper back as clinical markers of past severe sunburn: a case-control study.

BACKGROUND: Multiple solar lentigos commonly seen on the upper back and shoulders of adults are classically considered as a sign of photodamage, although epidemiological studies are scarce. AIM: To assess whether these lesions are clinical markers of past severe sunburn. METHODS: A case-control study in two outpatient dermatology clinics in French university hospitals. Past episodes of moderate and severe sunburn were compared between 145 adult patients with multiple solar lentigos on the upper back and 145 matched controls. RESULTS: In multivariate analysis adjusted for potential confounders, recalled episodes of sunburn during childhood, adolescence and adulthood were independently associated with the presence of multiple solar lentigos (adjusted odds ratios, 95% confidence intervals: 2.3 (1.1-5.2) and 28.1 (10.4-75.6) for moderate and severe sunburn, respectively). CONCLUSION: Multiple solar lentigos on the upper back and shoulders of adults are potential clinical markers of past severe sunburn which may thus be used to identify a population at higher risk of developing cutaneous malignant melanoma.

Poor agreement between self-reported and dermatologists' diagnoses for five common dermatoses.

BACKGROUND: Few epidemiological studies assessing the prevalence of chronic dermatosis are available in France and most of these studies have used biased samples drawn from specific subpopulations. As several recent studies have mentioned that self-reported diagnosis either underestimates or overestimates disease prevalence, the validity of such data is questionable. OBJECTIVES: To evaluate the agreement between self-reported and dermatologists' diagnoses for five chronic dermatoses: acne, eczema, fungal infection, psoriasis and seborrhoeic dermatitis, and to analyse the factors associated with patients' diagnosis knowledge. PATIENTS/METHODS: A cross-sectional study was conducted on the national day of skin tumour screening in April 2003. A self-administered questionnaire was completed by patients and a standard form was completed by dermatologists after clinical examination. A total of 4,622 adults were examined by a dermatologist in 134 screening centres across France. The agreement between self-reported and dermatologists' diagnoses was analysed using the kappa index. Characteristics of patients who were aware of their diagnosis were compared with those of patients who were not, by using multivariate logistic regression models. RESULTS: The demographic characteristics of the sample differed from those of the French population. The self-reported prevalence was significantly lower than the actual prevalence for all diseases except eczema. Underestimations ranging from 23% to 35% were observed in nearly all subgroups of our population. The agreement between self-reported and dermatologists' diagnoses was low to moderate. Many cases of chronic skin diseases were diagnosed in patients who did not report them. Diagnosis knowledge was poorer in those above 54 years of age and better for patients treated for the condition and those with impairment of social life. CONCLUSIONS: We observed a low agreement between self-reported and dermatologists' diagnoses for five chronic diseases. Self-reports underestimated the actual prevalence of four of five common diseases.