Mauro Pagani

Skin tests are of paramount importance for the evaluation of drug hypersensitivity reactions. Drug skin tests are often not carried out because of lack of concise information on specific test concentrations. The diagnosis of drug allergy is often based on history alone, which is an unreliable indicator of true hypersensitivity.To promote and standardize reproducible skin testing with safe and nonirritant drug concentrations in the clinical practice, the European Network and European Academy of Allergy and Clinical Immunology (EAACI) Interest Group on Drug Allergy has performed a literature search on skin test drug concentration in MEDLINE and EMBASE, reviewed and evaluated the literature in five languages using the GRADE system for quality of evidence and strength of recommendation. Where the literature is poor, we have taken into consideration the collective experience of the group.We recommend drug concentration for skin testing aiming to achieve a specificity of at least 95%. It has been possible to recommend specific drug concentration for betalactam antibiotics, perioperative drugs, heparins, platinum salts and radiocontrast media. For many other drugs, there is insufficient evidence to recommend appropriate drug concentration. There is urgent need for multicentre studies designed to establish and validate drug skin test concentration using standard protocols. For most drugs, sensitivity of skin testing is higher in immediate hypersensitivity compared to nonimmediate hypersensitivity.

Chemotherapeutic drugs have been widely used in the treatment of cancer disease for about 70 years. The development of new treatments has not hindered their use, and oncologists still prescribe them routinely, alone or in combination with other antineoplastic agents. However, all chemotherapeutic agents can induce hypersensitivity reactions (HSRs), with different incidences depending on the culprit drug. These reactions are the third leading cause of fatal drug-induced anaphylaxis in the United States. In Europe, deaths related to chemotherapy have also been reported. In particular, most reactions are caused by platinum compounds, taxanes, epipodophyllotoxins and asparaginase. Despite their prevalence and relevance, the ideal pathways for diagnosis, treatment and prevention of these reactions are still unclear, and practice remains considerably heterogeneous with vast differences from center to center. Thus, the European Network on Drug Allergy and Drug Allergy Interest Group of the European Academy of Allergy and Clinical Immunology organized a task force to provide data and recommendations regarding the allergological work-up in this field of drug hypersensitivity reactions. This position paper aims to provide consensus on the investigation of HSRs to chemotherapeutic drugs and give practical recommendations for clinicians that treat these patients, such as oncologists, allergologists and internists. Key sections cover risk factors, pathogenesis, symptoms, the role of skin tests, in vitro tests, indications and contraindications of drug provocation tests and desensitization of neoplastic patients with allergic reactions to chemotherapeutic drugs. Statements, recommendations and unmet needs were discussed and proposed at the end of each section.

Subcutaneous infusion ports (SIPs) represent a valid method for long-term chemotherapy. The SIPs have several advantages over other methods of venous access: they are easy to implant under local anaesthesia, have less discomfort for the patients, allow low costs, can be implanted in day hospital, and can be managed ambulatorily. However, SIPs have delayed complications, frequently related to clinical conditions of the neoplastic patients, and immediate complications, often due to the placement technique. From March 1992 to March 1997 we placed, under local anaesthesia and under fluoroscopic control, 102 SIPs in 99 general oncology patients for long-term chemotherapy (88% solid, 12% haematological tumours). The percutaneous venous access devices were in the subclavian vein in 96% of the cases and in the internal jugular vein in 4% of them. Immediate complications were: 1 haemopneumothorax, which required thoracic aspirations and two blood transfusions, 1 loop of the tunneled part of the catheter without alterations in SIP function, and 1 left jugular thrombosis in a patient with subclavian veins already thrombosed. The venous access was in the subclavian vein in the first 2 cases, and it was not necessary to suspend the therapeutic program. In the third instance, implanted in jugular vein, it was necessary to remove the SIP. Delayed complications were: 1 necrosis of the skin over the port, 1 infection of subcutaneous pocket, 2 infections of the system, 1 catheter deconnection, and 3 catheter ruptures with embolization of the catheter tip. The SIPs were removed in all cases but 1 in whom infection was successfully treated by appropriate antibiotic therapy. Embolization of the catheter required removal from the pulmonary artery under fluoroscopic guidance in the cardiac catheterization laboratory. In conclusion, infection and thrombosis are the two major complications of SIP in general oncology patients. In these cases it is not necessary to remove systematically the system, but a correct therapy (antibiotic, fibrinolytic agents) can be utilized with good results. The catheter rupture is often due to the wear over the costoclavicular angle. The interventional radiology is the method of choice in the treatment of the catheter embolization by rupture or dislocation. The experience of the surgical and nursing staff is probably the most important factor in decreasing the total rate of complications.

Not many studies have reported clinical experiences on effectiveness and safety of sublingual (swallowed) immunotherapy (SLIT) in patients with allergic, IgE-mediated reactions to latex (1, 2). In the studies quoted the scheduled SLIT (Table 1) includes a starting rush phase in 4 days, reaching the dose of 25 drops of the highest concentration. The same scheme is used in our allergy section, as proposed by the producer. The latex extract we employ (Alk-Abello’, Milan, Italy) is an ammoniacal extract quite similar to the one used in manufacturing latex gloves and other articles. So, it contains the major allergen Hev b 5, which is not found in the natural extract. The extract is standardized in w/v and, at his highest concentration, it contains 500 μg of proteins per millilitre. The present communication concerns a 36-year-old woman with latex allergy, affected by urticaria and asthma challenged by the handling or the exposition to latex articles and treated with SLIT. About 20 min after the maximum scheduled dose, the patient showed cutaneous rash and spreading urticaria followed at once by an asthma attack and a serious condition of anaphylactic shock with required treatment in emergency room. The reported case suggests the following remarks. Evidence based studies demonstrate that subcutaneous allergen-specific immunotherapy (SIT) is effective for the treatment of allergic respiratory diseases. However systemic reactions, sometimes severe can occur during SIT including occasional fatalities. For these reasons new vaccine with modified-allergens (s.c. allergoides) and a number of alternative methods of immunotherapy have been tried. Among the latter, SLIT proved effective and safe without the risk of severe systemic reactions observed with SIT (3). The high safety of the method allowed home administration. An analysis of published studies yielded the surprising result that SLIT with high doses is safer than SLIT with lower usual doses (4). In other words, it seems there is no correlation between doses increase and increased risk of adverse reactions. For this reason most allergists deem that rush SLIT can be practised without hazards, leading within days to a reduction of symptoms (5). These statements can be regarded as true in almost all cases, but exceptions to the rule exist. Uncommon cases of systemic reactions, sometime severe, have been observed during SLIT (6). The case here reported confirms that rare possibility. It is possible that, because of its excellent tolerability, benefits from rush SLIT largely overcome possible risks. The case we report is an anecdotic one. As for latex allergy, in spite of the previously quoted studies and waiting for the results of the other ones, we should consider that the rush phase of SLIT to latex is loaded a priori, as the rush SIT is, by higher risk of adverse events. In our opinion rush phase of SLIT to latex should always be performed in protected setting, where emergency treatment and intensive care room access must be available.

Mastocytosis is a clonal disorder characterized by the proliferation and accumulation of mast cells (MC) in different tissues, with a preferential localization in skin and bone marrow (BM). The excess of MC in mastocytosis as well as the increased releasability of MC may lead to a higher frequency and severity of immediate hypersensitivity reactions. Mastocytosis in adults is associated with a history of anaphylaxis in 22-49%. Fatal anaphylaxis has been described particularly following hymenoptera stings, but also occasionally after the intake of drugs such as nonsteroidal anti-inflammatory drugs, opioids and drugs in the perioperative setting. However, data on the frequency of drug hypersensitivity in mastocytosis and vice versa are scarce and evidence for an association appears to be limited. Nevertheless, clonal MC disorders should be ruled out in cases of severe anaphylaxis: basal serum tryptase determination, physical examination for cutaneous mastocytosis lesions, and clinical characteristics of anaphylactic reaction might be useful for differential diagnosis. In this position paper, the ENDA group performed a literature search on immediate drug hypersensitivity reactions in clonal MC disorders using MEDLINE, EMBASE, and Cochrane Library, reviewed and evaluated the literature in five languages using the GRADE system for quality of evidence and strength of recommendation.