Anticoagulant-related skin reactions

Cutaneous reactions have been reported during anticoagulant therapy with coumarin derivatives, unfractionated and low molecular weight heparins, heparinoids, danaparoid and hirudins. Anticoagulant-induced skin reactions vary from local allergic manifestations to skin necrosis. In patients with allergic reactions, diagnosis and crossreactions between anticoagulants can be confirmed by intracutaneous testing. Coumarin- and heparin-induced skin necrosis are rare, but are important side effects due to their high morbidity and occasional mortality. Cutaneous tests are contraindicated in these patients. In the future, anticoagulant strategies may include direct synthetic thrombin inhibitors (argatroban and melagatran/ximelagatran) and the Factor Xa inhibitor, pentasaccharide (fondaparinux).     

Skin manifestations of drug allergy

Cutaneous adverse drug reactions range from mild to severe and from those localized only to skin to those associated with systemic disease. It is important to distinguish features of cutaneous drug reactions which help classify the underlying mechanism and likely prognosis as both of these influence management decisions, some of which necessarily have to be taken rapidly. Severe cutaneous reactions are generally T cell-mediated, yet this immunological process is frequently poorly understood and principles for identification of the culprit drug are different to those of IgE mediated allergic reactions. Furthermore, intervention in severe skin manifestations of drug allergy is frequently necessary. However, a substantial literature reports on success or otherwise of glucocorticoids, cyclophsphamide, ciclosporin, intravenous immunoglobulin and anti-tumour necrosis factor therapy for the treatment of toxic epidermal necrolysis without clear consensus. As well as reviewing the recommended supportive measures and evidence base for interventions, this review aims to provide a mechanistic overview relating to a proposed clinical classification to assist the assessment and management of these complex patients.     

Hypersensitivity reactions to anticoagulant drugs

Drugs with anticoagulant activity, including heparins, hirudins, coumarins, and platelet aggregation inhibitors belong to the most widely used drugs. Hypersensitivity reactions from these agents are rare. However, due to their widespread use, they may have a considerable impact on patient safety and treatment. Accurate diagnosis of potentially life-threatening adverse events and identification of alternatives is mandatory. We review hypersensitivity reactions caused by the different groups of anticoagulant agents and discuss the pathophysiological mechanisms, diagnostic possibilities and management options. According to patients histories the most common hypersensitivity reaction is intolerance to acetylsalicylic acid (ASA). Also localized erythematous plaques, occurring to subcutaneous application of heparins are rather common. Other hypersensitivity reactions are rare but may be life-threatening, e.g. skin necrosis due to heparin-induced thrombocytopenia. Rarely anaphylactoid reactions have been observed to ASA, heparin, and hirudin. Skin and provocation tests with immediate and late readings are the most reliable diagnostic tools for heparin- or hirudin-induced urticaria/anaphylaxis or heparin-induced delayed plaques. Provocation tests may be used to identify safe alternatives. In cases of necrosis from heparins or coumarins, all in vivo tests are contraindicated. Most in vitro tests are not universally available, and with the exception of platelet aggregation tests, they have a low sensitivity. In some anticoagulant-associated hypersensitivity reactions detailed allergologic investigation may help to identify safe treatment alternatives. Typically, several tests are needed, and therefore the test procedures are time consuming.     

Anticoagulation with anisindione in a patient with a warfarin-induced skin eruption

A 71-year-old woman experienced a pruritic, maculopapular, morbilliform rash on her lower extremities 5 days after starting warfarin for recurrent deep vein thrombosis. The rash extended to her truncal areas and progressively worsened until somewhat painful vesicular lesions developed. Warfarin was discontinued, and subcutaneous injections of enoxaparin were begun; the rash resolved. In addition to a history of deep vein thrombosis, the patient had experienced a hypersensitivity skin reaction to warfarin in the past that necessitated withdrawal of the drug and placement of a vena caval filter. Because no clear consensus exists on whether dyes used in compounding warfarin play a causative role or whether allergic cross-sensitivity occurs among the coumarin derivatives, the patient was rechallenged with a dye-free warfarin 10-mg tablet. The pruritic rash returned along with the vesicular lesions and continued to worsen until the warfarin was discontinued again. The patient subsequently was given oral anticoagulant therapy with anisindione, an indanedione, and her symptoms resolved completely. Health care providers managing patients who are receiving oral anticoagulant therapy should be aware of the maculopapular allergic reactions associated with warfarin and consider alternative treatment options such as anisindione.     

Cross-reactivity in cell-mediated and IgE-mediated hypersensitivity to glucocorticoids

In the last few decades, glucocorticoids have received increasing attention for their capability of provoking systemic hypersensitivity reactions, when administered orally, parenterally, or intralesionally, as well as allergic skin and mucosal symptoms, when applied locally to the skin in patients with contact dermatitis or to the mucosa in patients with asthma and/or rhinitis. However, because of their anti-inflammatory and immunosuppressive properties, glucocorticoids are often not suspected of such hypersensitivity reactions. In addition, because glucocorticoids retain their anti-inflammatory potential, even if they act as sensitizers, the signs and symptoms of allergic reactions are not always obvious, particularly when they overlap with those caused by the very diseases glucocorticoids are used to treat. Moreover, interpretation of diagnostic tests, specifically that of patch-test reactions, can be difficult. In this review, particular attention is addressed to the problem of allergenic cross-reactivity among topical and systemic glucocorticoids. We also look at the clinical and practical aspects of both cell-mediated and IgE-mediated hypersensitivity reactions to glucocorticoids and their consequences on anti-inflammatory therapeutic choices.     

Inhibition of anaphylaxis like reaction and mast cell activation by Sitagliptin

Mast cells stimulation activates degranulation process resulting in releasing of mediators, such as histamine. In this study, the effect of aqueous extract of sitagliptin, a selective dipeptidylpeptidase-4 inhibitor, on the mast cell-mediated allergic response was studied with the possible mechanisms of action, focusing on the histamine release and pro-inflammatory cytokine secretion in mast cells. Sitagliptin produced dose dependent inhibition in compound 48/80-induced systemic reactions. In addition, sitagliptin attenuated IgE-mediated skin allergic reaction. Sitagliptin dose-dependently reduced compound 48/80- and IgE-induced histamine release from mast cells. Sitagliptin decreased the secretion of pro-inflammatory cytokines, tumor necrosis factor-α, in mast cells. So, the finding of this study provides evidence that sitagliptin inhibits mast cell derived allergic reactions, and involvement of pro-inflammatory cytokine secretion in such effects.     

咪康唑莫米松皮肤成膜凝胶皮肤用药安全性试验

目的对咪康唑莫米松皮肤成膜凝胶进行皮肤刺激性试验和过敏性试验,为,临床用药安全提供依据。方法采用家兔进行皮肤刺激试验,分为完整皮肤组和破损皮肤组,连续给药7d后观察;采用豚鼠皮肤进行主动过敏性试验（ACA）,观察咪康唑莫米松皮肤成膜凝胶是否引起豚鼠皮肤或全身过敏反应。结果家兔皮肤刺激性试验,完整皮肤组和破损皮肤组均未出现红斑、水肿等现象;豚鼠皮肤主动过敏性试验,未引起皮肤过敏反应或全身过敏反应。结论咪康唑莫米松皮肤成膜凝胶未引起家兔皮肤刺激性反应和豚鼠皮肤过敏性反应,其临床用药剂量安全可靠。     

综合护理在螺旋CT增强扫描中的应用价值

目的：探讨护理配合工作在螺旋CT增强扫描中的重要性,以保证增强扫描成功,减少意外和变态反应的发生。方法：对增强扫描患者认真做好扫描前的准备、扫描中的观察,及扫描后意外情况的处理。结果：增强扫描6700例患者,6686例获得良好的增强扫描图像,成功率为99.79%。发生重度过敏1例（0.02%）,轻中度过敏22例（0.33%）,造影剂注射失败14例（0.21%）。无造影剂渗漏致局部皮肤坏死、空气栓塞及过敏死亡病例。结论：在增强扫描中,护理人员认真准备、严密观察,就能取得较好的增强效果,提高病灶的检出率,也能减少患者意外情况的发生。     

Skin reactions due to anti-epileptic drugs: several case-reports with long-term follow-up

In this study, the clinical findings and management of allergic skin reactions induced by the most used antiepileptic drugs, Lamotrigine (LMT) and Carbamazepine (CBZ), were evaluated. Lamotrigine is an antiepileptic drug recently released in several countries; it is effective for a variety of seizure types in adults and children, both as an add-on agent and in monotherapy, and it is generally well tolerated. Clinical and epidemiologic evidence suggest serious cutaneous reactions to antiepileptic drugs are more likely to occur during the first 8 weeks and they appear to increase when drugs are administered with other anticonvulsants, such as Valproate (VPA). We selected 10 patients who presented an idiosyncratic skin rash when treated with carbamazepine (8 patients) and lamotrigine (2 patients) administered as monotherapy, and we followed up on these patients for several years. Seven reactions were mild/severe cutaneous eruptions; one Toxic Epidermal Necrolysis, a case of Stevens-Johnson and a case of Hypersensitivity Syndrome. All severe skin drug reactions were induced by Carbamazepine. In five patients the AEDs were ceased abruptly (sometimes with the administration of a different molecule), tapered in four and continued unchanged in one. We conclude that the discontinuation of the drug with substitution with another is the most effective treatment and that corticosteroids are helpful in mild cutaneous reactions, while in severe skin reactions, such as Toxic Epidermal Necrolysis, corticosteroids are only a complementary therapy since intravenous immunoglobulins are the first choice treatment.     

Cost-effectiveness analysis of six strategies for cardiovascular surgery prophylaxis in patients labeled penicillin allergic.

The cost-effectiveness of different approaches to antimicrobial prophylaxis for cardiovascular surgery patients labeled penicillin allergic was studied. A decision-analytic model was used to examine the cost-effectiveness of six strategies for antimicrobial prophylaxis in cardiovascular surgery patients at a tertiary care hospital. The strategies consisted of (1) giving vancomycin to all patients labeled penicillin allergic, (2) giving cefazolin to all patients labeled penicillin allergic, (3) giving vancomycin to all patients with a history suggesting an immunoglobulin E (IgE)-mediated reaction to penicillin and cefazolin to patients without such a history, (4) administering a penicillin skin test to patients with a history suggesting an IgE-mediated reaction to penicillin and giving vancomycin to patients with positive results and cefazolin to all others, (5) skin testing all patients labeled penicillin allergic and giving vancomycin to those with positive results and cefazolin to those with negative results, regardless of history, and (6) skin testing all patients and giving vancomycin to those with positive results or a history suggesting an IgE-mediated reaction to penicillin and cefazolin to all others. Giving cefazolin to all patients labeled penicillin allergic was the least expensive strategy but was associated with the highest rate of both anaphylactic and non-life-threatening serious reactions. Selective use of vancomycin in patients with a history suggesting an IgE-mediated reaction to penicillin was associated with an added cost and a slightly lower rate of anaphylaxis. Although skin-testing strategies may decrease both non-life-threatening and anaphylactic reactions, the incremental cost was high. When vancomycin was given to all patients labeled penicillin allergic, the incremental cost was very high. A decision-analytic model indicated that selective use of vancomycin is more cost-effective than indiscriminate use of vancomycin for surgical prophylaxis in cardiovascular surgery patients labeled penicillin allergic.     

Skin: major target organ of allergic reactions to small molecular weight compounds

Skin is a major target organ for allergic reactions to small molecular weight compounds. Drug allergic reactions may be life-threatening such as in the case of anaphylactic reactions or bullous drug reactions and occur in about 5% of all hospitalized patients. Allergic contact dermatitis has an enormous influence on the social life of the patient because it is the most frequent reason for occupational skin diseases and the treatment and prevention of this disease cost approximately euro 3 billion per year in Germany. The different proposed pathophysiological pathways leading to a drug eruption are discussed in this paper. All major enzymes which are involved in the metabolism of xenobiotica were shown to be present in skin. Evidence supporting the role of metabolism in the development of drug allergy and allergic contact dermatitis is demonstrated in the example of sulphonamides and fragrances.     

Anaphylaxis to lidocaine with tolerance to articaine in a 12 year old girl

True allergic reactions to local anesthetics are extremely rare and constitute less than 1% of all reactions. In addition, many of those allergic reactions are caused by the preservative constituents of the local anesthetics. Here we report a 12 year old girl with anaphylaxis to lidocaine (an amide local anesthetic) on two occasions. The allergy was confirmed by positive skin prick test to the drug. Skin testing and challenge to another amide local anesthetic (articaine) were negative. Subsequently, its use was well tolerated in a dental procedure. Up to our knowledge, this is the first report of a patient who is allergic to lidocaine and tolerant to articaine.Abbreviations: LA, local anesthetic; SPT, skin prick test; SQ, subcutaneous     

Adverse reactions to practolol in hospitalized patients

Summary Adverse reactions to practolol were studied in 198 prospectively monitored hospitalized medical patients. The mean age of the practolol recipients was 57 years; angina and cardiac arrhythmias were the most common indications for therapy. Adverse reactions were attributed to practolol in 20 patients (10%). Fifteen of these twenty reactions involved impairment of cardiac function (bradyarrhythmias, heart block, congestive heart failure, hypotension), and in three instances the reaction was considered life-threatening. Three additional patients had cutaneous reactions attributed to the drug. Adverse reactions to practolol were not dose-related, but toxicity appeared to be more frequent among patients concurrently receiving quinidine. The frequency of cardiovascular complications of propranolol in a similar series of patients was nearly identical. However, no skin reactions were attributed to propranolol. The findings suggest that practolol and propranolol produce unwanted cardiovascular effects with nearly equal frequency among hospitalized patients. Cutaneous reactions to practolol are evident even during short-term use.     

Action of Dracocephalum argunense on mast cell-mediated allergy model

The discovery of drugs for the treatment of allergic disease is an important subject in human health. Stimulation of mast cells starts the process of degranulation resulting in releasing of mediators, such as histamine. In this report, we investigated the effect of aqueous extract of Dracocephalum argunense Fisch. (Labiatae) (DAAE) on the mast cell-mediated allergic response and studied its possible mechanisms of action, focusing on the histamine release and pro-inflammatory cytokine secretion in mast cells. DAAE inhibited compound 48/80-induced systemic reactions and serum histamine release in mice. In addition, DAAE attenuated IgE-mediated skin allergic reaction. DAAE dose-dependently reduced IgE-induced histamine release from mast cells. The level of cAMP was transiently increased by treatment of DAAE. DAAE specifically blocked the phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-induced p38 mitogen-activated protein kinase (MAPK) activation. DAAE decreased the secretion of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 in mast cells. Our findings provide evidence that DAAE inhibits mast cell derived allergic reactions, and involvement of cAMP for histamine release and p38 MAPK for pro-inflammatory cytokine secretion in these effects.     

Management of food allergies

Worldwide, ～ 8 and 2% of children and adults, respectively, suffer from food allergy. Cow’s milk, egg, peanut, soy, wheat, fish, shellfish and tree nuts are responsible for the majority of allergic reactions to foods. Allergic reactions to food can occur by a variety of immune mechanisms including: IgE-mediated; non-IgE-mediated (T-cell-mediated); and combined IgE- and T-cell-mediated. Food allergies can affect any organ system, but most frequently involve the gastrointestinal system, the skin and the respiratory system. Knowledge of the spectrum of food allergies is important in order to identify patients at risk for severe or life-threatening allergic reactions. This article will review the mechanisms of specific food allergy disorders. It will also summarise the diagnosis of food allergy including the history of a food reaction, skin tests and laboratory tests. The management of food allergy will also be discussed with particular emphasis on the avoidance of food allergens and the pharmacotherapy of allergic reactions. Future therapy for food allergies will also be discussed.     

复方环磷腺苷乳膏毒性研究

目的:考察复方环磷腺苷乳膏经皮肤给药的安全性.方法:将不同剂量的复方环磷腺苷乳膏和基质用于白色豚鼠背部正常或破损去毛区皮肤,观察皮肤急性毒性、刺激性反应和动物的过敏情况.结果:复方环磷腺苷乳膏未产生急性毒性反应;反复致敏后使用,也无皮肤与全身过敏反应;一次或多次给药对豚鼠正常皮肤无刺激性.对破损皮肤有轻度刺激性,但给药后 48 h 或 72 h,这种刺激性消失.结论:复方环磷腺苷乳膏未产生急性毒性和过敏反应,也无明显刺激性反应.     

Diagnosis and treatment of allergic skin disorders in the elderly.

Allergic skin disorders in the elderly may arise from contact with or ingestion of offending allergens. Itching associated with skin allergy must be distinguished from other causes of itching in the elderly such as xerosis, itching due to systemic disease and bullous disease. Although elderly people have somewhat decreased cell-mediated immunity and may be harder to sensitise under experimental conditions, they have had many years to acquire allergic responses, and therefore develop contact dermatitis frequently. Patch testing is a valuable tool to diagnose contact allergy and should be used often in the elderly, particularly in patients at high risk of contact dermatitis, such as those with chronic lower extremity dermatitis or ulcers due to venous stasis. When prescribing topical medications to high risk patients, a knowledge of the common sensitisers is important. In addition to allergy to medicaments and dressings used to treat stasis ulcers, contact allergy to dental prostheses and medications used to treat ocular disease are common in the elderly as a result of increased usage and exposure. Rash caused by ingested allergens is much more commonly due to medications than to food in the elderly. Allergic noneczematous dermatoses in the elderly are commonly drug-induced. Urticarial skin reactions are often associated with the administration of antibacterials, nonsteroidal anti-inflammatory drugs (NSAIDs), antidepressants or opioids. Morbilliform rashes are a common sign of systemic reaction to anticonvulsants, gold, allopurinol or diuretics. Phototoxic reactions may be associated with the administration of tetracyclines, diuretics, NSAIDs and antihyperglycaemic agents. Patient-specific variables such as HLA type and concomitant medication may affect the likelihood of an allergic response to medication. Many elderly patients take multiple medications, which can make diagnosis of drug allergy difficult because diagnosis is most commonly accomplished by observing clinical response once the medication is withdrawn. In the case of lichenoid cutaneous reactions, clinical improvement may take several months after withdrawal of the offending drug. Laboratory tests to detect drug-induced allergic skin disorders may be available in the future.     

Unique immunomodulatory effects of azelastine on dendritic cells in vitro

Allergic contact dermatitis and atopic dermatitis are among the most common inflammatory skin diseases in western countries, and antigen-presenting cells like dendritic cells (DC) are key players in their pathophysiology. Histamine, an important mediator of allergic reactions, influences DC maturation and cytokine secretion, which led us to investigate the immunomodulatory potential of the well-known histamine H1 receptor antagonists: azelastine, olopatadine, cetirizine, and pyrilamine. Unlike other H1 antihistamines, azelastine decreased lipopolysaccharide-induced tumor necrosis factor α and interleukin-12 secretion from murine bone marrow-derived DC. This effect was independent of histamine receptors H1, H2, or H4 and may be linked to inhibition of the nuclear factor kappa B pathway. Moreover, only azelastine reduced proliferation of allogenic T cells in a mixed leukocyte reaction. We then tested topical application of the H1 antihistamines on mice sensitized against toluene-2,4-diisocyanate, a model of Th2-mediated allergic contact dermatitis. In contrast to the in vitro results, all investigated substances were efficacious in reducing allergic ear swelling. Azelastine has unique effects on dendritic cells and T cell interaction in vitro. However, this did not translate into superior in vivo efficacy for Th2-mediated allergic dermatitis, possibly due to the effects of the antihistamines on other cell types involved in skin inflammation. Future research will have to clarify whether these properties are relevant to in vivo models of allergic inflammation with a different T cell polarization.     

Hypersensitivity reactions to cephalosporins

At present, cephalosporins represent one of the most prescribed classes of antibiotics. Although allergic reactions have been estimated to be infrequent, the number of reactions to cephalosporins is increasing due to their wide use. Cross-reactivity with penicillins has mainly been evaluated in patients with penicillin allergy. It is higher between first- and second-generation cephalosporins with the same or similar side chain than between cephalosporins with different side chains. Unlike penicillins, cephalosporin haptens or determinants have not been defined, and therefore the diagnosis is complicated. Nevertheless, skin tests with cephalosporins are useful in the evaluation of several allergic reactions. Although more studies are necessary, a negative result in skin testing to penicillin and cephalosporins with different side chains seems to be a good predictor of tolerance, and could be used in select cases.     

Management of food allergies

Worldwide, approximately 8 and 2% of children and adults, respectively, suffer from food allergy. Cow's milk, egg, peanut, soy, wheat, fish, shellfish and tree nuts are responsible for the majority of allergic reactions to foods. Allergic reactions to food can occur by a variety of immune mechanisms including: IgE-mediated; non-IgE-mediated (T-cell-mediated); and combined IgE- and T-cell-mediated. Food allergies can affect any organ system, but most frequently involve the gastrointestinal system, the skin and the respiratory system. Knowledge of the spectrum of food allergies is important in order to identify patients at risk for severe or life-threatening allergic reactions. This article will review the mechanisms of specific food allergy disorders. It will also summarise the diagnosis of food allergy including the history of a food reaction, skin tests and laboratory tests. The management of food allergy will also be discussed with particular emphasis on the avoidance of food allergens and the pharmacotherapy of allergic reactions. Future therapy for food allergies will also be discussed.