Proposal for a 6-step approach for differential diagnosis of neonatal erythroderma.

The broad differential diagnosis of neonatal erythroderma often poses a diagnostic challenge. Mortality of neonatal erythroderma is high due to complications of the erythroderma itself and the occasionally severe and life-threatening underlying disease. Early correct recognition of the underlying cause leads to better treatment and prognosis. Currently, neonatal erythroderma is approached on a case-by-case basis. The purpose of this scoping review was to develop a diagnostic approach in neonatal erythroderma. After a systematic literature search in Embase (January 1990 - May 2020, 74 cases of neonatal erythroderma were identified, and 50+ diagnoses could be extracted. Main causes were the ichthyoses (40%) and primary immunodeficiencies (35%). Congenital erythroderma was present in 64% (47/74) of the cases, predominantly with congenital ichthyosis (11/11; 100%), Netherton syndrome (12/14, 86%) and Omenn syndrome (11/23, 48%). Time until diagnosis ranged from 102 days to 116 days for cases of non-congenital erythroderma and congenital erythroderma respectively. Among the 74 identified cases a total of 17 patients (23%) died within a mean of 158 days and were related to Omenn syndrome (35%), graft-versus-host disease (67%) and Netherton syndrome (18%). Disease history and physical examination are summarized in this paper. Age of onset and a collodion membrane can help to narrow the differential diagnoses. Investigations of blood, histology, hair analysis, genetic analysis and clinical imaging are summarized and discussed. A standard blood investigation is proposed, and the need for skin biopsies with lympho-epithelial Kazal-type related Inhibitor staining is highlighted. Overall, this review shows that diagnostic procedures narrow the differential diagnosis in neonatal erythroderma. A 6-step flowchart for the diagnostic approach for neonatal erythroderma during the first month of life is proposed. The approach was made with the support of expert leaders from international multidisciplinary collaborations in the European Reference Network Skin-subthematic group Ichthyosis.

Predicting recurrence in patients with sentinel node-negative melanoma: validation of the EORTC nomogram using population-based data.

BACKGROUND: Identifying patients with sentinel node (SN)-negative melanoma who are at greatest risk of recurrence is important. The European Organization for Research and Treatment of Cancer (EORTC) Melanoma Group proposed a prognostic model that has not been validated in population-based data. The EORTC nomogram includes Breslow thickness, ulceration status and anatomical location as parameters. The aim of this study was to validate the EORTC model externally using a large national data set. METHODS: Adults with histologically proven, invasive cutaneous melanoma with a negative SN biopsy in the Netherlands between 2000 and 2014 were identified from the Dutch Pathology Registry, and relevant data were extracted. The EORTC nomogram was used to predict recurrence-free survival. The predictive performance of the nomogram was assessed by discrimination (C-statistic) and calibration. RESULTS: A total of 8795 patients met the eligibility criteria, of whom 14·7 per cent subsequently developed metastatic disease. Of these recurrences, 20·9 per cent occurred after the first 5 years of follow-up. Validation of the EORTC nomogram showed a C-statistic of 0·70 (95 per cent c.i. 0·68 to 0·71) for recurrence-free survival, with excellent calibration (R2 = 0·99; P = 0·999, Hosmer-Lemeshow test). CONCLUSION: This population-based validation confirmed the value of the EORTC nomogram in predicting recurrence-free survival in patients with SN-negative melanoma. The EORTC nomogram could be used in clinical practice for personalizing follow-up and selecting high-risk patients for trials of adjuvant systemic therapy.

Predicting sentinel node positivity in patients with melanoma: external validation of a risk-prediction calculator (the Melanoma Institute Australia nomogram) using a large European population-based patient cohort.

BACKGROUND: A nomogram to predict sentinel node (SN) positivity [the Melanoma Institute Australia (MIA) nomogram] was recently developed and externally validated using two large single-institution databases. However, there remains a need to further validate the nomogram's performance using population-based data. OBJECTIVES: To perform further validation of the nomogram using a European national patient cohort. METHODS: Patients with cutaneous melanoma who underwent SN biopsy in the Netherlands between 2000 and 2014 were included. Their data were obtained from the Dutch Pathology Registry. The predictive performance of the nomogram was assessed by discrimination (C-statistic) and calibration. Negative predictive values (NPVs) were calculated at various predicted probability cutoffs. RESULTS: Of the 3049 patients who met the eligibility criteria, 23% (691) were SN positive. Validation of the MIA nomogram (including the parameters Breslow thickness, ulceration, age, melanoma subtype and lymphovascular invasion) showed a good C-statistic of 0·69 (95% confidence interval 0·66-0·71) with excellent calibration (R2 = 0·985, P = 0·40). The NPV of 90·1%, found at a 10% predicted probability cutoff for having a positive SN biopsy, implied that by using the nomogram, a 16·3% reduction in the rate of performing an SN biopsy could be achieved with an error rate of 1·6%. Validation of the MIA nomogram considering mitotic rate as present or absent showed a C-statistic of 0·70 (95% confidence interval 0·68-0·74). CONCLUSIONS: This population-based validation study in European patients with melanoma confirmed the value of the MIA nomogram in predicting SN positivity. Its use will spare low-risk patients the inconvenience, cost and potential risks of SN biopsy while ensuring that high-risk patients are still identified.

Sentinel node biopsy in patients with melanoma improves the accuracy of staging when added to clinicopathological features of the primary tumor.

BACKGROUND: It has been claimed, without supporting evidence, that knowledge of sentinel node (SN) status does not provide more accurate prognostic information than basic clinicopathological features of a primary cutaneous melanoma. We sought to investigate this claim and to quantify any additional value of SN status in predicting survival outcome. PATIENTS AND METHODS: Data for a Dutch population-based cohort of melanoma patients (n = 9272) and for a validation cohort from a large Australian melanoma treatment center (n = 5644) were analyzed. Patients were adults diagnosed between 2004 and 2014 with histologically-proven, primary invasive cutaneous melanoma who underwent SN biopsy. Multivariable Cox proportional hazards analyses were carried out in the Dutch cohort to assess recurrence-free survival (RFS), melanoma-specific survival (MSS) and overall survival (OS). The findings were validated using the Australian cohort. Discrimination (Harrell's C-statistic), net benefit using decision curve analysis and net reclassification index (NRI) were calculated. RESULTS: The Dutch cohort showed an improved C-statistic from 0.74 to 0.78 for OS and from 0.74 to 0.76 for RFS when SN status was included in the model with Breslow thickness, sex, age, site, mitoses, ulceration, regression and melanoma subtype. In the Australian cohort, the C-statistic increased from 0.70 to 0.73 for OS, 0.70 to 0.74 for RFS and 0.72 to 0.76 for MSS. Decision curve analyses showed that the 3-year and 5-year risk of death or recurrence were more accurately classified with a model that included SN status. At 3 years, sensitivity increased by 12% for both OS and RFS in the development cohort, and by 10% and 6% for OS and RFS, respectively, in the validation cohort. CONCLUSIONS: Knowledge of SN status significantly improved the predictive accuracy for RFS, MSS and OS when added to a comprehensive suite of established clinicopathological prognostic factors. However, clinicians and patients must consider the magnitude of the improvement when weighing up the advantages and disadvantages of SN biopsy for melanoma.

Expanding spectrum of "spitzoid" lesions: a small series of 4 cases with MAP2K1 mutations.

The molecular background of a significant proportion of spitzoid neoplasms is still unknown. Recently, activating mutations in MAP2K1 have been described in a few spitzoid lesions, but not in benign Spitz nevi. We report four cases of melanocytic tumors with spitzoid features in which a MAP2K1 mutation was detected. The lesions did not show a single distinct phenotype and ranged from benign to malignant. Two cases resembled desmoplastic Spitz nevi. Based on the combination of morphological, immunohistochemical, and molecular findings, one case was classified as benign, one as probably benign, possibly intermediate low-grade (MELTUMP-melanocytic tumor of unknown malignant potential), one case was classified as intermediate (MELTUMP), and one case was considered a superficial spreading melanoma with spitzoid features. Based on this, we conclude that MAP2K1 mutations can indicate a spitzoid genetic signature and can be found in both benign and malignant spitzoid neoplasms.

Thick melanomas without lymph node metastases: A forgotten group with poor prognosis.

INTRODUCTION: Although adjuvant therapy is available for melanoma patients with sentinel lymph node (SLN) metastases (pN+), this is not the case for thick melanomas without SLN involvement (pN-). OBJECTIVES: We assessed overall and relative survival (OS, RS) in patients with >4.0 mm Breslow thickness (BT) pN- and pN + melanomas and ≤4.0  mm pN+ patients. MATERIALS AND METHODS: Clinicopathological data were retrieved from a cohort of >4.0 mm thick and/or pN + melanoma patients in The Netherlands from 2000 to 2014. OS and RS was compared using Kaplan-Meier-curves. A Cox-regression-model was developed to assess determinants of OS in >4.0 mm pN- patients. RESULTS: In 54 645 patients, 3940 (7.2%) had >4.0 mm thick melanomas. SLN biopsy was performed in 1150 (29.2%) patients. Five-year OS was 70.5% for >4.0 mm pN- and 48.1% for >4.0  mm pN+ patients (p < 0.001), with a decreasing trend in OS for every mm BT. Five-year OS in 1877 ≤ 4.0  mm pN+ patients was 71.5%, which was not different from >4.0 mm pN- (p = 0.24). Higher age, higher BT category, ulceration and male gender were significantly associated with poor survival in >4.0 mm pN- patients. CONCLUSIONS: Thick pN- melanomas have a poor prognosis, comparable to that of less thick pN + melanomas, which is not accounted for in current guidelines. We encourage including these high-risk patients in adjuvant trials.

Intra-nodal nevi in sentinel node-negative patients with cutaneous melanoma does not influence survival.

BACKGROUND: Melanoma patients with intra-nodal nevi (INN) and without melanoma metastasis in the sentinel lymph node biopsy (SLNB) are generally treated as patients with negative SLNB. However, diagnosis of INN may be difficult and nodal melanoma metastases may falsely be regarded as INN. OBJECTIVES: Our aim was to evaluate the clinical significance of INN in the SLNB in patients with primary cutaneous melanoma on a nationwide level in The Netherlands by comparing survival between three groups: patients with INN and without nodal melanoma metastasis (INN group), patients without INN and without nodal melanoma metastasis (negative SLNB group) and patients with nodal melanoma metastasis irrespective of INN (positive SLNB group). METHODS: Data were obtained from 'PALGA', the Dutch Nationwide Network and Registry of Histopathology and Cytopathology, yielding a cohort of adults with histologically proven, primary, invasive cutaneous melanoma patients in The Netherlands diagnosed between 2000 and 2014 who underwent SLNB. Clinical and pathological variables were extracted from the pathology text files. Differences between patients with INN, negative SLNB and positive SLNB were analysed using Kaplan-Meier analysis. RESULTS: A total of 11 274 patients were eligible for inclusion. The prevalence of INN in the SLNB was 5.0%. Melanomas with INN had similar median Breslow thickness compared to melanomas with negative SLNB and were more frequently located on trunk and upper limbs and observed in younger patients compared to melanomas with negative and positive SLNB. Overall survival of patients with INN showed no significant difference compared with negative SLNB (median follow-up of 5.7 years of all patients). CONCLUSIONS: As there seems to be no difference in overall survival between patients with INN and negative SLNB, the diagnosis of INN seems to be reliable. Current practice to treat patients with INN as patients with negative SLNB appears to be appropriate.

Sex matters: men with melanoma have a worse prognosis than women.

BACKGROUND: In Europe, one of the highest melanoma incidences is found in the Netherlands. Like in several other European countries, females are more prone to develop melanoma as compared to males, although survival is worse for men. OBJECTIVE: To identify clinicopathological gender-related differences that may lead to gender-specific preventive measures. METHODS: Data from the Dutch Nationwide Network and Registry of Histopathology and Cytopathology (PALGA) were retrieved from patients with primary, cutaneous melanoma in the Netherlands between 2000 and 2014. Patients initially presenting as stage I, II and III without clinically detectable nodal disease were included. Follow-up data were retrieved from the Netherlands Cancer Registry. Gender-related differences were assessed, and to compare relative survival between males and females, multivariable relative excess risks (RER) were calculated. RESULTS: A total of 54.645 patients were included (43.7% men). In 2000, 41.7% of the cohort was male, as compared to 47.3% in 2014 (P < 0.001). Likewise, in 2000, 51.5% of the deceased cohort was male compared to 60.1% in 2014 (P < 0.001). Men had significantly thicker melanomas at the time of diagnosis [median Breslow thickness 1.00 mm (interquartile range (IQR): 0.60-2.00) vs. 0.82 mm (IQR: 0.50-1.50) for females] and were significantly older at the time of diagnosis, more often had ulcerated melanomas and melanomas localized on the trunk or head and neck. Over time, survival for females improved while that of men decreased (P < 0.001). RER for dying was 1.37 (95% CI: 1.31-1.45) for men in multivariable analysis. CONCLUSION: There are evident clinicopathological differences between male and female melanoma patients. After multivariable correction for all these differences, relative survival remains worse for men. Clinicians as well as persons at risk for melanoma should be aware of these differences, as awareness and prevention might lead to a lower incidence and mortality of melanoma. This indicates the need of prevention campaigns integrating and targeting specific risk profiles.

Management of acute food allergic reactions by general practitioners.

BACKGROUND: Food is one of the leading causes of anaphylaxis. In the Netherlands, patients visit a general practitioner (GP) as often as an emergency department (ED) in case of an acute food allergic reaction. So far, the management of food allergic reactions by GPs has not been investigated. Therefore, we explored the management of acute food allergic reactions by GPs regarding specific treatment, observation period, prescription of emergency medication to treat new episodes, diet advices and referral to a specialist. METHODS: A questionnaire containing three hypothetical cases (two anaphylactic and one mild case) with questions about their management was sent to 571 GPs. RESULTS: Overall, treatment choice was dependent on the severity of the reaction (mild vs. anaphylaxis, P < .001). However, epinephrine was used for treatment of anaphylaxis with mainly respiratory symptoms in only 27% and for anaphylaxis with mainly cardiovascular symptoms in 73%. At discharge, the percentages for prescription of self-injectable epinephrine were 53% and 77%, respectively. A short observation period of <2 hours was advised by 42% of general practitioners in case of anaphylaxis. CONCLUSIONS: Treatment of food induced anaphylaxis by GPs appears to be suboptimal: a considerable number of patients would not be treated with epinephrine for the acute reaction (especially anaphylactic cases with respiratory symptoms), the observation period chosen by GPs was often too short and self-injectable epinephrine was not always prescribed at discharge to treat possible new episodes. Education programs are needed to increase the awareness of GPs to recognize and treat anaphylactic reactions.

Acquired cutis laxa in childhood Sweet's syndrome.

In Sweet's syndrome, the essential features are the characteristic morphology of the lesions, their histologic appearance, the dramatic response to corticosteroids and the absence of scarring. We report an 8-month-old infant in whom Sweet's syndrome was diagnosed and who developed acquired cutis laxa in the skin lesions.

High prevalence of esophageal involvement in lichen planus: a study using magnification chromoendoscopy.

BACKGROUND AND STUDY AIMS: The first cases of squamous cell carcinoma in esophageal lichen planus were recently described. We performed a study to establish the prevalence of endoscopic and histopathologic abnormalities consistent with lichen planus and (pre-) malignancy in a cohort of patients with lichen planus. PATIENTS AND METHODS: A total of 24 patients with lichen planus were prospectively studied using high-magnification chromoendoscopy. Focal esophageal abnormalities were mapped, classified, and biopsied. Biopsies were also taken from normal-appearing esophageal mucosa at three levels (proximal, middle, and distal). The presence of a lymphohistiocytic interface inflammatory infiltrate and Civatte bodies (i. e. apoptotic basal keratinocytes) at histopathologic examination was considered diagnostic for esophageal lichen planus. Symptoms were assessed using validated questionnaires. RESULTS: A total of 38 focal abnormalities were biopsied. These consisted of: layers of mucosa peeling off, hyperemic lesions, papular lesions, submucosal plaques/papules, a flat polypoid lesion, and segments of cylindrical epithelium. No endoscopic signs of dysplasia were present. Esophagitis consistent with gastroesophageal reflux disease was noted in 12 / 24 patients. Histopathology showed chronic inflammation of the esophageal mucosa in the majority (18 / 24) of patients. In 50 % (12 / 24), the diagnosis of esophageal lichen planus was made. Dysplasia was not present. There were no differences in symptoms between patients with and without esophageal lichen planus. CONCLUSIONS: At screening endoscopy a high prevalence (50 %) of esophageal lichen planus was found in patients with orocutaneous lichen planus. No dysplasia was found.

[The practice guideline 'Acne' (second revision) from the Dutch College of General Practitioners; a response from the perspective of dermatology]. / De standaard 'Acne' (tweede herziening) van het Nederlands huisartsen Genootschap; reactie vanuit de dermatologie.

The second revised practice guideline 'Acne' from the Dutch College of General Practitioners contains adequate and scientifically well-supported recommendations for the management of patients with acne. There are some concerns about the initial treatment steps in these guidelines which only allow very slow progress to systemic therapy. This might, in some cases, lead to inadequate treatment of patients with more severe acne.

The polymorphous light eruption-severity assessment score does not reliably predict the results of phototesting.

BACKGROUND: Polymorphous light eruption (PLE) is a very common photodermatosis in which patient history is highly specific. Phototesting is used to confirm the diagnosis and to determine the action spectrum and the severity of this disease. In daily practice and in research studies, it would be convenient to assess disease severity by patient history only. OBJECTIVES: This study aims to assess PLE disease severity via patient history and compares this with severity assessment via phototesting. PATIENTS AND METHODS: Sixty-one patients with PLE were asked 10 standard questions and all were phototested. The answers to the standard questions were coded with linear scores ranging from 0 to 10. The score of each question was plotted as independent variable in a multiple linear regression model against the score of the phototest (minimal number of irradiations necessary to elicit a positive skin lesion, with a maximum of 6 irradiations) as dependent variable using an enter approach. Furthermore, the scores of the separate questions were added to form a total score, the PLE-severity assessment score (PLE-SAS). The medians of these PLE-SASs were compared with the result scores obtained by phototesting. Phototesting was done with ultraviolet A and ultraviolet B irradiation. RESULTS: Fifty-seven of the 61 patients had a positive test result (93%). Using the multiple linear regression model, the severity assessment by patient history (PLE-SAS) compared with the result of phototesting showed two significant contributing questions (adjusted PLE-SAS) (P < 0.05) but with a regression coefficient of 0.2. A significant difference in median scores with the severity assessment (PLE-SAS and adjusted PLE-SAS) between patients testing positive after 1-3 irradiations compared with those testing positive after 4-6 irradiations was present (P < 0.05). However, the overlap quartile range between both groups was such that the PLE-SAS and the adjusted PLE-SAS have little predictive value in individual patients. CONCLUSIONS: We showed that in PLE, disease severity as determined using the PLE-SAS or adjusted PLE-SAS did not reliably predict severity as assessed by phototesting. Two significant contributing questions were not discriminating enough to be used as predicting questions to assess severity. Accurate patient history proved to be a reliable method to diagnose PLE. Phototesting is useful to determine the responsible ultraviolet action spectrum and to exclude differential diagnoses like photosensitive eczema, lupus erythematosus or chronic actinic dermatitis. PLE-SAS cannot replace phototesting for determining the severity of PLE.

[Skin eruptions as an adverse reaction to epidermal growth-factor receptor inhibitors]. / Huidafwijkingen als bijwerking van remmers van epidermale-groeifactorreceptor.

Inhibition of the epidermal growth-factor receptor (EGFR) is a new strategy in the treatment of solid malignancies. Two men, aged 65 and 59 years, with a metastasized renal carcinoma and a 51-year-old man with a metastasized melanoma developed an acneiform eruption during EGFR inhibition. The second and third patient also developed paronychia. Treatment in all patients consisted of antiseptics and topical antibiotics; the first and third patient also received an oral antibiotic. Withdrawal of the EGFR inhibitor because of progression of the disease led to complete recovery of the cutaneous lesions in the first and the third patient; both died after several months. In the second patient, the side effects reached an acceptable level during continued EGFR therapy. EGFR inhibition is usually accompanied by cutaneous side effects. An acneiform eruption is seen in up to 90% of all treated patients. Other side effects include dry skin, and nail and hair changes. The pathogenesis of these side effects is related to inhibition of EGFR signalling pathways in the skin, but is not yet fully understood. The treatment of EGFR inhibitor-mediated cutaneous toxicity is based mainly on clinical experience.

Home ultraviolet B phototherapy for psoriasis: discrepancy between literature, guidelines, general opinions and actual use. Results of a literature review, a web search, and a questionnaire among dermatologists.

BACKGROUND: Home ultraviolet B (UVB) phototherapy is a debated treatment. It is currently being prescribed for patients with psoriasis, although literature on the subject is scarce. Despite the apparent contradiction between clinical practice and literature, no systematic study of either has been conducted. OBJECTIVES: To assess and compare the available publications and guidelines about home UVB phototherapy for psoriasis with the actual opinions and use of this therapy. METHODS: The literature and guidelines were searched using databases, search engines and e-mail. A postal survey of 343 Dutch dermatologists and 142 dermatologists from 32 other countries was carried out; 255 and 102 dermatologists respectively responded. Outcome measures were the reported advantages, drawbacks and prescription rates of home UVB phototherapy. RESULTS: Fourteen publications (nonrandomized) and six guidelines concerning home UVB phototherapy for psoriasis were identified. Most were reticent about the use of this treatment. Publications describing nonclinical research (7/14) reported most of the drawbacks mentioned (24/31). Home UVB phototherapy was prescribed to 5% (median) of all patients with psoriasis in The Netherlands who required UVB. However, 28% (68/244) of the Dutch dermatologists prescribed home UVB in 20 to 100% of their cases. Dermatologists from other countries reported that 0-10% of UVB treatments were offered at home. For both Dutch and other dermatologists, the most important reasons for prescribing home UVB concerned time and travel distance (80%, i.e. 163 of 205 and 75%, i.e. 33 of 44). Therapy-related drawbacks (such as poor service and equipment) were the objections mentioned most often (55%, i.e. 103 of 186 and 63%, i.e. 57 of 91). Concerns about the medicolegal liability of home UVB were rarely expressed by individual respondents, but frequently mentioned in the various reports. CONCLUSIONS: A discrepancy exists between the actual use of home UVB phototherapy and the general opinions found in publications. The treatment is prescribed for a considerable number of patients despite the fact that literature and guidelines advise caution. Personal and nonevidence-based opinions on this therapy are widespread while randomized clinical studies have thus far not been conducted.

[Body dysmorphic disorder in 3-8% of patients in outpatient dermatology and plastic surgery clinics]. / Stoornis in de lichaamsbeleving bij 3-8% van de patiënten op de poliklinieken Dermatologie en Plastische Chirurgie.

OBJECTIVE: To determine the 6-month prevalence of body dysmorphic disorder (BDD) in outpatient clinics of dermatology and plastic surgery in a university medical centre. DESIGN: Questionnaire study. METHOD: In the period January 2004-June 2004, the self-reported Body dysmorphic disorder questionnaire was completed by 530 and 475 new patients in the outpatient clinics of dermatology and plastic surgery, respectively. The dermatologist or plastic surgeon assessed the severity of the defect. To meet the DSM-IV criteria for BDD, the patient must have been preoccupied with treatment of all or part of their appearance, experienced obvious suffering or restriction of function with minimal or no defect present (defect score 1 or 2). RESULTS: In the outpatient clinics ofdermatology and plastic surgery 8.5% (95% CI: 6.1-10.9) and 3.2% (95% CI: 1.7-4.7) of patients screened positive for BDD, respectively. CONCLUSION: A high prevalence of BDD was found in the outpatient clinics ofdermatology and plastic surgery. Because dermatologists and plastic surgeons do not often recognise BDD, a simple screening tool is needed.

[Increased consultations and numbers of sexually transmitted diseases at the STD clinic of Utrecht, 1994-2002]. / Toename van het aantal bezoeken en seksueel overdraagbare aandoeningen op de soa-polikliniek van Utrecht, 1994-2002.

OBJECTIVE: To determine trends in numbers of visitors and their demographic characteristics, reasons for visit, number of STDs and high-risk groups. DESIGN: Secondary analysis of registration data. METHOD: Data of every client that visited the STD clinic in Utrecht, the Netherlands, were aggregated from 1994 to 2002 in order to analyse trends. RESULTS: The number of visitors as well as the number of STDs rose strongly over the period investigated. The age of the visitors decreased. In 1994 17% of the visitors was born outside the Netherlands, in 2002 6%. The majority of the clients (56%) visited the STD clinic to get themselves tested preventively and 27% came because of symptoms. Visitors with symptoms or who were warned by others had a three-fold increased risk of having an STD. Other risk groups were: homosexual men, visitors born outside the Netherlands and visitors who have had an STD before. Groups with an increased risk of having a Chlamydia trachomatis infection were: visitors aged under 34 years old and visitors born in Morocco, Surinam and the Antilles. The number of Chlamydia infections rose sharply among homosexual male visitors. CONCLUSION: The increase in the number of visitors and of STD requires an increase in STD prevention, aimed at high-risk groups. More research is needed into the limited help-seeking behaviour of immigrants and more attention needs to be paid to Chlamydia trachomatis infections among homosexual men.