[Erythema nodosum due to cat-scratch-disease: An association and important therapeutic implications]. / Érythème noueux compliquant une maladie des griffes du chat : une association et des implications thérapeutiques à connaître.

INTRODUCTION: Cat-scratch disease is a zoonosis caused by Bartonella henselae and transmitted mostly through a break in the skin. This infectious disease is commonly characterized by a benign lymphadenitis. However, more unusual presentations have been observed. CASE REPORT: We report the case of a 44-year-old woman with cat-scratch disease who developed subsequently an erythema nodosum. The non-steroidal anti-inflammatory treatment of the erythema nodosum may have led to worsening of cat-scratch disease with an abscess requiring surgical treatment. CONCLUSION: Cat-scratch disease is an uncommon and poorly known cause of erythema nodosum, and must be systematically ruled out. As non-steroidal anti-inflammatory drug are usually prescribed as a treatment of erythema nodosum, it should be used cautiously to reduce the risk of complications in the cat-scratch disease.

[Multiple erythema annulare centrifugum associated with knee monoarthritis revealing Capnocytophagacanimorsus infection]. / Erythème annulaire centrifuge multiple et monoarthrite révélateurs d'une infection à Capnocytophaga canimorsus.

INTRODUCTION: Capnocytophagacanimorsus (C. canimorsus), a commensal Gram-negative bacillus found in the oral cavity of dogs and cats, is pathogenic for humans, with the most common clinical manifestations being septicemia, meningitis and endocarditis. Herein we report a case of CC bacteremia manifesting as multiple plaques of erythema annulare centrifugum associated with monoarthritis of the knee. PATIENTS AND METHODS: A 66-year-old man consulted for a skin rash and monoarthritis of the right knee with fever following an insect bite on his right hallux. Cutaneous examination revealed numerous erythematous annular plaques on the trunk and limbs with centrifugal extension. Analysis of synovial fluid from the right knee showed an inflammatory liquid with a sterile bacteriological culture and PCR was negative for Borrelia. C. canimorsus bacteria were isolated from blood cultures. 16S RNA PCR performed on the synovial fluid was positive for the same organism. The patient's history revealed that his hallux wound had been licked by his dog. DISCUSSION: C. canimorsus most frequently affects immunosuppressed subjects. Cutaneous signs are seen in half of all cases, most frequently presenting as cellulitis, pathological livedo or thrombotic purpura. We report herein a case of CC bacteremia in an immunocompetent patient manifesting as multiple plaques of erythema annulare centrifugum, an unusual sign, and monoarthritis of one knee.

[Acute generalized pustular bacterid followed by Sweet's syndrome and erythema nodosum]. / Pustulose aiguë généralisée post-streptococcique suivie d'un syndrome de Sweet et d'un érythème noueux.

INTRODUCTION: Streptococcal infections can cause various skin manifestations related to the direct action of the offending organism itself or to a reactional mechanism. Reactional manifestations are less well known and understood, and they include generalized acute pustulosis belonging to the spectrum of neutrophilic dermatoses. We report a case of generalized acute pustulosis followed by Sweet syndrome and erythema nodosum occurring after a streptococcal infection. PATIENTS AND METHODS: A 60-year-old woman was consulting for a diffuse pustular rash after a throat infection, with high levels of anti-streptolysin (337 U/L) and anti-streptodornase (2560 U/L). The biopsy showed folliculitis and a neutrophilic infiltrator of the dermis, and bacteriological and mycological cultures were sterile. The patient then developed papules evoking Sweet syndrome followed by nodules typical of erythema nodosum after 20 days. A favourable outcome was achieved under colchicine. DISCUSSION: Generalized acute pustulosis is a form of neutrophilic dermatosis whose mechanisms, area predilection and treatment are poorly known. The clinical presentation of this patient was initially typical and the secondary progression to lesions like those in Sweet syndrome is consistent with the pathophysiological continuity and overlap of these entities.

Lyme borreliosis and other tick-borne diseases. Guidelines from the French scientific societies (II). Biological diagnosis, treatment, persistent symptoms after documented or suspected Lyme borreliosis.

The serodiagnosis of Lyme borreliosis is based on a two-tier strategy: a screening test using an immunoenzymatic technique (ELISA), followed if positive by a confirmatory test with a western blot technique for its better specificity. Lyme serology has poor sensitivity (30-40%) for erythema migrans and should not be performed. The seroconversion occurs after approximately 6 weeks, with IgG detection (sensitivity and specificity both>90%). Serological follow-up is not recommended as therapeutic success is defined by clinical criteria only. For neuroborreliosis, it is recommended to simultaneously perform ELISA tests in samples of blood and cerebrospinal fluid to test for intrathecal synthesis of Lyme antibodies. Given the continuum between early localized and disseminated borreliosis, and the efficacy of doxycycline for the treatment of neuroborreliosis, doxycycline is preferred as the first-line regimen of erythema migrans (duration, 14 days; alternative: amoxicillin) and neuroborreliosis (duration, 14 days if early, 21 days if late; alternative: ceftriaxone). Treatment of articular manifestations of Lyme borreliosis is based on doxycycline, ceftriaxone, or amoxicillin for 28 days. Patients with persistent symptoms after appropriate treatment of Lyme borreliosis should not be prescribed repeated or prolonged antibacterial treatment. Some patients present with persistent and pleomorphic symptoms after documented or suspected Lyme borreliosis. Another condition is eventually diagnosed in 80% of them.

[Idiopathic granulomatous mastitis associated with erythema nodosum]. / Mastite granulomateuse idiopathique associée à un érythème noueux.

BACKGROUND: Idiopathic granulomatous mastitis (IGM) is a rare, chronic, granulomatous, inflammatory disorder with potentially misleading clinical and radiological features. IGM is diagnosed after exclusion of infectious or tumoral diseases. Herein we report a case of erythema nodosum associated with IGM, which serves as a reminder that erythema nodosum may constitute an extra-mammary sign of IGM. PATIENTS AND METHODS: A 36-year-old nulliparous woman presented with fever and skin rash at our dermatology clinic at the North Franche-Comté hospital in July 2017. Symptoms had occurred 2 days previously. The patient had a fever of 38.8°C and typical erythema nodosum on the limbs. Physical examination showed an irregular, inflammatory, abscessed mass measuring 20cm with multiple shrinkage zones that had been developing for 4 weeks and for which breast examinations were being performed. Laboratory tests showed an inflammatory state (CRP 155mg/mL, WBC 14.6×109/L), other tests (serum electrolytes and calcium, hepatic and renal tests, Streptotest, T-spot, HIV, HBV, HCV serology, anti-streptolysin, anti-streptodornase, local microbiology samples, antinuclear antibodies, soluble antigens antibodies, hemocultures, angiotensin-converting-enzyme and chest x-rays) were normal. Microbiology investigations were negative. Mammography revealed invasive mastitis. Breast sample biopsies showed giant cell granulomas without caseous necrosis or tumor cells, and histochemical staining (PAS, Ziehl, Grocott, Gram) was negative. The final diagnosis was of IGM associated with erythema nodosum. Symptoms rapidly improved with oral steroids. DISCUSSION: As reported herein, erythema nodosum may be associated with IGM and support the diagnosis thereof. This association is rare, with fewer than 30 case reports described in the literature. IGM is an uncommon benign disorder of the breast that can mimic two frequent breast disorders: breast carcinoma and breast abscess. It usually occurs in young sexually active women. It appears as a tumor with an inflammatory solid painful mass, with nipple and skin retraction, occasionally with abscesses and accompanied by homolateral axillary lymphadenopathies. Radiologic findings are usually not specific for or suggestive of cancer. The histopathological picture of IGM is characterized by the presence of multinucleated giant cells and epithelioid histiocytes forming non-caseating granulomas around lobules. Minor ductal and periductal inflammation is usually present. IGM is rarely associated with autoimmune system manifestations, especially erythema nodosum, arthritis, episcleritis or hidradenitis suppurativa. Although the physiopathology of IGM remains unclear, this case serves as additional evidence that the etiology of IGM is of autoimmune origin. While there is no recommendation for the treatment of IGM, oral steroids remain the cornerstone of therapy. CONCLUSION: We report a case of IGM associated with erythema nodosum. Dermatologists must be aware of this association.

Lyme borreliosis and other tick-borne diseases. Guidelines from the French Scientific Societies (I): prevention, epidemiology, diagnosis.

Lyme borreliosis is transmitted en France by the tick Ixodes ricinus, endemic in metropolitan France. In the absence of vaccine licensed for use in humans, primary prevention mostly relies on mechanical protection (clothes covering most parts of the body) that may be completed by chemical protection (repulsives). Secondary prevention relies on early detection of ticks after exposure, and mechanical extraction. There is currently no situation in France when prophylactic antibiotics would be recommended. The incidence of Lyme borreliosis in France, estimated through a network of general practitioners (réseau Sentinelles), and nationwide coding system for hospital stays, has not significantly changed between 2009 and 2017, with a mean incidence estimated at 53 cases/100,000 inhabitants/year, leading to 1.3 hospital admission/100,000 inhabitants/year. Other tick-borne diseases are much more seldom in France: tick-borne encephalitis (around 20 cases/year), spotted-fever rickettsiosis (primarily mediterranean spotted fever, around 10 cases/year), tularemia (50-100 cases/year, of which 20% are transmitted by ticks), human granulocytic anaplasmosis (<10 cases/year), and babesiosis (<5 cases/year). The main circumstances of diagnosis for Lyme borreliosis are cutaneous manifestations (primarily erythema migrans, much more rarely borrelial lymphocytoma and atrophic chronic acrodermatitis), neurological (<15% of cases, mostly meningoradiculitis and cranial nerve palsy, especially facial nerve) and rheumatologic (mostly knee monoarthritis, with recurrences). Cardiac and ophtalmologic manifestations are very rarely encountered.

[Insights on the management of Lyme disease]. / Actualités sur la prise en charge de la maladie de Lyme.

Lyme disease is currently a hot topic in France due to a high incidence in some areas. Its clinical polymorphism can lead to misdiagnosis on one hand and to unjustified treatment on the other hand. Clinical symptoms vary considerably according to involved organs (skin, central and/or peripheral nervous system, joints, heart, eyes) and may be limited to or associated with general non-specific signs. Biological exams must be guided by clinical symptoms to help diagnosis and treatment decision according to clinical history, presentation, time of onset and duration of symptoms. However, to date, no serologic test can discriminate between past and active disease. The role of the internist is two-fold: make a diagnosis when faced with general or focal symptoms and avoid inappropriate attribution to Lyme disease of symptoms related to alternate diagnoses.

[Histopathology of cutaneous drug reactions]. / Histopathologie des réactions cutanées médicamenteuses.

There are many different types of cutaneous adverse reactions. The most classical reactions are driven by T lymphocytes that specifically react towards a drug, with an individual genetic susceptibility linked to certain type I major histocompatibility complex alleles. These reactions are characterized by a wide variety of clinical and histopathological presentations, and a wide range of severity. The most frequent entity is the maculopapular rash, while the most aggressive forms are the Steven-Johnson syndrome and toxic epidermal necrolysis (SJS-TEN). The histopathological alterations associated to each of these syndromes have been better described in the literature during the past 10 years, encompassing non-specific lesions, as in most drug induced maculopapular rashes, to more specific inflammatory patterns. The finding of confluent apoptotic keratinocytes with epidermal detachment is the prototypical aspect of SJS-TEN. There are however numerous pitfalls, and a similar aspect to those observed in each cutaneous drug reactions entities can be found in other diseases. DRESS syndrome can indeed present with dense and epidermotropic T-cell infiltrate, sometimes with nuclear atypias, and thus can be difficult to distinguish from a primary or secondary cutaneous T-cell lymphoma. The diagnosis of cutaneous adverse reactions relies on a clinical-pathological confrontation and requires an accurate evaluation of drug imputability.

[Amoxicillin-induced skin rash sparing a plaque of erythema migrans: Renbök phenomenon: Case report and literature review]. / Toxidermie à l'amoxicilline épargnant une plaque d'érythème migrant : phénomène de Renbök et revue de la littérature.

INTRODUCTION: Renbök phenomenon describes the inhibition of a lesion when a different one appears. We describe the first case of Renbök phenomenon occurring in a context of erythema migrans (EM) spared by an amoxicillin-induced skin rash and we also present a literature review. CASE REPORT: A 60-year-old patient was treated with amoxicillin for EM on the right knee and subsequently developed generalized erythema as a result of an antibiotic-induced skin rash, with sparing of the area previously affected by EM. Renbök phenomenon was diagnosed. DISCUSSION: In 1981, Cochran et al. first described a maculopapular drug reaction, which spared the sites of previous X irradiation for a tumor. Since then, nearly 40 cases have been reported, mostly describing patient with alopecia areata of the scalp with hair growth within plaques of psoriasis. One of the mechanisms suggested is a role played by cytokine cross-regulation in competition among distinct immune responses. CONCLUSION: We report the first case of Renbök phenomenon involving EM spared by a drug reaction. This phenomenon provides an insight into inflammatory response competition within a single patient.

[A new case of Rowell's syndrome]. / Un nouveau cas de syndrome de Rowell.

INTRODUCTION: This article introduces a new case of Rowell's syndrome, a controversial entity defined by the association of lupus erythematosus and erythema multiforme. OBSERVATION: A 43-year-old woman was diagnosed with lupus erythematosus induced by esomeprazole. Because her eruption did not improve after withdrawal of the drug, hydroxychloroquine was administered. Two weeks later, the patient described new annular lesions on her chest and arms, both erosive and crusted, and some had a target-like appearance. The oral mucosa was also affected. Histology revealed sub-epidermal blistering with keratinocytic necrosis, strongly suggesting erythema multiforme. Screening for other causes of erythema multiforme proved negative. A positive outcome was achieved with corticosteroids and hydroxychloroquine. One year later, the patient was in complete remission for both lupus erythematosus and erythema multiforme. DISCUSSION: The association of lupus erythematosus and erythema multiforme first described in 1963 is known as Rowell's syndrome. While diagnostic criteria have been established in the literature, the reality of this entity is still contested. The annular lesions of subacute lupus erythematosus may be confused with the lesions of erythema multiforme. As suggested in the above section, other authors consider Rowell's syndrome to be a singular entity. Indeed, our patient developed lesions distinct from those initially suggesting subacute lupus erythematosus, in particular: the target-like aspect of the elementary lesions, mucosal involvement, a distinct histological aspect, and dissociated outcomes. Ultimately, the definition of Rowell's syndrome remains highly debated.

[Chronic recurrent annular neutrophilic dermatosis]. / Dermatose neutrophilique annulaire récurrente chronique.

BACKGROUND: Chronic recurrent annular neutrophilic dermatosis (CRAND) is a rare form of neutrophilic dermatosis characterised by chronic annular progression, histological impairment similar to that seen in Sweet's syndrome and the absence of association with generalised signs, abnormal laboratory values or underlying systemic disease. Herein we report two new cases. PATIENTS AND METHODS: Case no 1. A 41-year-old woman had presented with four annular lesions on the forearms and neckline which she had had for one year. Examination revealed a 5-cm annular lesion on the right forearm and four similar adjacent lesions. The condition spontaneously resolved after 4 weeks. Treatment with hydroxychloroquine 400mg per day for three months proved ineffective in preventing a further episode. However, following treatment with colchicine at a daily dose of 1mg for two months, no further relapses in the rash occurred over a 10-year observation period. Case no 2. A 38-year-old woman consulted for recurrent annular erythema confined to the legs. Examination showed the presence of a red papular annular lesion on the right leg, encircling a yellowish macule with a central ring of fine scale; the lesion had been present for three weeks. Treatment with colchicine was initiated but the patient was lost to follow-up. In both cases, histological examination was evocative of Sweet's syndrome but no inflammatory or neutrophilic syndrome and no underlying systemic disease were demonstrated. DISCUSSION: CRAND presents as a stereotypical and benign form of neutrophilic dermatosis. A diagnosis of chronic recurrent annular dermatosis with gyrate progression should be considered in the absence of general signs, neutrophilia or underlying systemic disease.

[Cutaneous panniculitis]. / Panniculites cutanées.

Panniculitis is an inflammation of the subcutaneous fat. Skin biopsy plays a critical role in the differential diagnosis of panniculitis. The most common approach to diagnosis relies on the differentiation between predominantly septal or lobular panniculitis, followed by the distinction between lesions with and without vasculitis. It is also very important to submit a part of the skin biopsy for microbiological analysis and for T-cell clonal expansion if T-cell lymphoma is suspected. Erythema nodosum, the most frequent septal panniculitis, has many causes and in its typical clinical presentation, does not require skin biopsy. In other panniculitis, diagnosis is based on the integration of the clinical and histological data, which renders a deep cutaneous biopsy necessary. Periarteritis nodosa, a septal panniculitis with vasculitis characterized by subcutaneous nodules and livedo racemosa, can be associated with systemic involvement. Nodular thrombophlebitis needs search for associated coagulopathy, Behçet's disease, periarteritis nodosa or Buerger's disease. Lobular panniculitis are classified according to the nature of cells present in the inflammatory infiltrate. If there is a lymphocytic infiltration, lupus panniculitis is difficult to differentiate from subcutaneous panniculitis-like T-cell lymphoma. If there are histiocytes, it can be a sarcoidosis, a cytophagic histiocytic panniculitis or, in newborn, a subcutaneous fat necrosis. Neutrophilic panniculitis needs careful clinic-pathologic correlation. Treatment of panniculitis can be challenging and is based on the histopathological findings. Frequently, the precise cause of panniculitis cannot be established from the outset, so it is important to follow-up patients and not hesitate to repeat the skin biopsy.

[Fixed drug eruption to clarithromycin: The importance of challenge tests in diagnosis]. / Érythème pigmenté fixe à la clarithromycine : importance des tests de provocation pour le diagnostic.

BACKGROUND: Determining the substance responsible for recurrent fixed drug eruption (FDE) may be difficult in the case of patients on multiple medication. Allergy testing may prove invaluable in such situations, as we demonstrate herein with an original case. PATIENTS AND METHODS: A 49-year-old man presented a rash on the seventh day of treatment with esomeprazole, clarithromycin and amoxicillin prescribed for gastritis involving Helicobacter pylori. The condition regressed spontaneously within a few days, but left three areas of hyperpigmentation. The patient subsequently reported four further episodes consisting of stereotypical reactivation in the areas of the three initial lesions and occurring 24hours after use of clarithromycin (2 episodes) and amoxicillin (2 episodes). The patient resumed proton pump inhibitor therapy (esomeprazole) without incident. Based on history taking, an initial diagnosis was made of multiple fixed drug eruption involving amoxicillin and clarithromycin. The initial skin allergy investigations were negative (patch-tests for amoxicillin and clarithromycin on healthy skin on the patient's back and on the affected area). After discussion, we decided to reintroduce the suspected drugs in succession. Beginning with clarithromycin, 12h after a single dose of 250mg, we noted an erythematous reaction on the pigmented areas, together with a burning sensation. In an identical challenge test with amoxicillin (500mg), the latter drug was perfectly well tolerated, ruling out the diagnosis of FDE to amoxicillin and thus the diagnosis of multiple FDE suggested by the patient history. DISCUSSION: FDEs to macrolides are rare, and herein we report a new case. Our observation confirms the diagnostic value of challenge tests in FDE. These tests should only be performed in the event of non-severe FDE, in other words not in bullous or systemic reactions, and they often constitute the only diagnostic approach possible, since skin tests are rarely positive during investigation for FDE.

[Cutaneous manifestations of sarcoidosis]. / Manifestations cutanées de la sarcoïdose.

Sarcoidosis is a systemic granulomatous disorder of unknown aetiology. Its dermatological manifestations are extremely polymorphous. They are normally classed as either specific lesions, comprising granulomas, which are generally chronic, or non-specific lesions, principally acute erythema nodosum. These signs are seen in around 25% of sarcoidosis patients. The disease may be heralded by a skin disorder. Diagnosis of cutaneous sarcoidosis provides the clinician with three problems: screening for a visceral site of the disease, determination of the prognosis, and long-term management with regular monitoring coupled with suitable therapy in the event of cosmetic or functional impairment.