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Resume Introduction Pour la premiere fois, deux observations nous permettent de souligner qu’en cas de toxidermie au cours d’un traitement associant deux medicaments, un test positif a l’un des deux n’autorise pas la reprise sans surveillance du second. Observations Un homme avait eu une urticaire apres un traitement par pristinamycine puis ceftriaxone. Les tests epicutanes aux synergistines etaient tous positifs, les patch-tests, prick-tests et intradermo-reactions aux betalactamines etaient negatifs. Le test de provocation oral (TPO) a la ceftriaxone etait positif. Une femme developpait sous spiramycine un exantheme maculopapuleux lentement regressif malgre une substitution par cefixime et corticotherapie. Les patch-tests, prick-tests et intradermo-reactions aux macrolides et betalactamines etaient negatifs. Le TPO au cefixime etait positif ; mais le TPO avec la spiramycine l’etait egalement. Discussion Une sensibilisation a deux antibiotiques sans parente chimique peut survenir lors de la meme toxidermie sans notion de sensibilisation anterieure a ces classes medicamenteuses. Les mecanismes en cause dans ce phenomene restent a discuter. Ces observations soulignent que tout medicament suspect lors d’une toxidermie necessite une reintroduction sous surveillance hospitaliere, meme si des tests cutanes ou TPO etaient positifs avec d’autres medicaments pris simultanement.

Resume Introduction La bonne sensibilite (Se) de la tomoscintigraphie par emission de positons couplee a la tomodensitometrie (TEP-TDM) lui a fait prendre place dans la prise en charge des melanomes. Elle pose cependant un probleme de faux positifs. L’imagerie en resonance magnetique (IRM) corps entier est une methode nouvelle qui beneficie de progres considerables. Objectifs L’objectif de cette etude etait d’evaluer la sensibilite et la specificite (Sp) de l’IRM corps entier avec sequence de diffusion dans la detection des metastases de melanome, en comparaison a la TEP-TDM. Patients et methodes Il s’agissait d’une etude prospective, concernant des melanomes de tous stades. La TEP-TDM, l’IRM et une TDM etaient realisees le meme jour. Pour chaque examen, le nombre de lesions par patient etait calcule. Les strategies de prise en charge proposees immediatement apres la TEP-TDM puis l’IRM etaient comparees. Resultats Quarante patients ont ete inclus, totalisant 72 metastases repertoriees. La TDM a detecte 53 metastases (Se 80 %, Sp 95 %). La TEP-TDM a detecte 53 metastases, mais 4 faux positifs (Se 74 %, Sp 89 %). L’IRM corps entier en a detecte 59, avec deux faux positifs (Se 83 %, Sp 96 %). La sensibilite de l’IRM etait superieure a celle de la TEP-TDM pour les localisations hepatiques et renales. Les traitements proposes apres TEP-TDM et IRM differaient dans trois cas : un patient etait surclasse par l’IRM, deux autres par la TEP-TDM. La realisation d’un examen corps entier a, a elle seule, influence le traitement de quatre patients (10 %). Conclusion l’IRM corps entier, moins couteuse que la TEP-TDM et non irradiante, pourrait prendre place dans la prise en charge des patients suivis pour melanomes.

PET/CT has proven extremely useful in the management of melanoma patients, with great sensitivity (Se), but it tends to give false-positive results. Whole-body MRI (wb-MRI) is a new method that has made considerable progress.The aim of this study was to assess the Se and specificity (Sp) of wb-MRI with a diffusion sequence for detecting melanoma metastasis compared to PET/CT.This was a prospective study, including patients at any AJCC (American Joint Committee on Cancer) stage of melanoma. PET/CT, wb-MRI and CT, including the brain, were performed on the same day. For each of the three exams, the number of lesions per patient was counted. The treatments proposed by the doctor immediately after PET/CT and then MRI were compared.Forty patients were included and a total of 72 metastases were noted. CT detected 53 of these metastases (Se 80%, Sp 95%), while PET/CT detected 53 metastases, with four false-positive (Se 74%, Sp 89%) and Wb-MRI detected 59, with two false-positive (Se 83%, Sp 96%). The sensitivity of MRI was distinctly superior to PET/CT for both hepatic and pulmonary lesions. The treatment proposed after PET/CT and MRI differed in three cases: one patient was falsely reclassified by MRI (AJCC IV instead of IIB) while two others were falsely reclassified by PET/CT (AJCC IV instead of IB and IIIC). Exclusively whole-body scan influenced the treatment of four patients (10%).Wb-MRI with diffusion sequence, which is less costly than PET/CT and is also non-radioactive, could play an important role in the detection of metastases in melanoma patients.

For the first time, 2 cases highlight the fact that, in the event of cutaneous adverse drug reactions under treatment associating 2 drugs, a positive test with one of the 2 does not authorize further readministration of the remaining drug without hospital surveillance.A man had urticaria during treatment with pristinamycin subsequently replaced by ceftriaxon. All the patch-tests with synergistins were positive, whereas patch-tests, prick-tests and intradermal tests with betalactams were negative. The oral challenge with ceftriaxon was positive. A woman taking spiramycin developed a maculopapular rash which was slowly regressive despite substitution with cefixim and corticotherapy. Patch-tests, prick-tests and intradermal tests with macrolides and betalactams were negative. An oral challenge with spiramycin was positive.Sensitization to two antibiotics without shared chemical structures can occur during the same episode of a cutaneous adverse drug reaction, even without prior indication of sensitization to these drug classes. The mechanisms at play in this phenomenon are still debated, but this highlights the fact that reintroduction of any drug suspected at the time of a cutaneous adverse drug reaction must be performed under hospital surveillance, whatever the degree of imputability and even if skin tests with other drugs taken simultaneously were positive.