Selective hypersensitivity to boiled razor shell.

Many types of seafood require cooking before ingestion and it has been demonstrated that this cooking process may affect the antigenicity and allergenicity of the food. We describe a case of anaphylaxis caused by selective sensitization to razor shell, a mollusc. In vivo and in vitro studies confirmed sensitization to boiled razor shell. Analysis of the nature of the allergen yielded results that were consistent with the findings of other authors and suggested that allergens involved in seafood allergy are commonly high molecular weight proteins that, in most cases, are heat stable.

Allergy to cloxacillin with normal tolerance to amoxicillin and cefuroxime.

BACKGROUND: Cloxacillin is a semisynthetic penicillin widely used in nonmethicillin resistant Staphylococcus aureus infections. Several hypersensitivity reactions to cloxacillin have been reported, although IgE-mediated allergic reactions to the drug are rare and there is little information about possible tolerance to other semisynthetic penicillins or cephalosporins in patients with cloxacillin allergy. We present 2 patients with demonstrated IgE-mediated allergy to cloxacillin and tolerance to amoxicillin and cefuroxime. CASE REPORTS: Case 1. A 47-year-old woman began treatment with cloxacillin due to acute cellulitis. After ingesting 500 mg of the drug, she experience generalized maculopapular eruption and facial angioedema. Case 2. A 55-year-old woman presented an episode of acute urticaria and labial angioedema 60 minutes after ingesting 500 mg of cloxacillin for a skin abscess. METHODS AND RESULTS: Skin prick tests were positive to cloxacillin in case 1 and negative in case 2. However, an intradermal test was positive to cloxacillin (2 mg/ml) in case 2. Simple-blind oral challenge tests with amoxicillin (1 g) and cefuroxime (500 mg) were well-tolerated by both patients. CONCLUSIONS: We present 2 patients allergic to cloxacillin with normal tolerance to other betalactam antibiotics, confirming that cross-reactivity among these antibiotics seems to be uncommon. Complete allergy study, including an oral challenge test, should be considered in these patients.

Anaphylaxis to oral furosemide.

Furosemide, one of the most used diuretic drugs, rarely induces type-1 allergic reactions It is included in the non-aromatic sulfonamides but a cross-reactivity mechanism between this group and the sulfonamides antibiotics, has not been clearly demonstrated. A 24-year-old woman, 10 minutes after the intake of one pill of Seguril 40mg experienced oral itching, generalized urticaria, facial angioedema, dyspnea and hypotension. She recovered after the administration of parental adrenaline, methyl-prednisolone and dyphenhydramine. An skin prick test with furosemide (10 mg/ml) was negative. The intradermal skin tests were positive to furosemide (1 %) as well as sulfamethoxazole (0.03 mg/ml), with 10 atopic and non-atopic negative controls. The patient rejected the performance of an oral challenge test with sulfamethoxazole. IgE-mediated reactions to furosemide are infrequent, but it could be the cause of life-threatening reactions. We have reported a case of anaphylaxis after the oral administration of furosemide with a demonstrated hypersensitivity mechanism through the positive intradermal skin test. The previous administration of the drug could probably the mechanism of sensitization, but the positive intradermal test to sulfamethoxazole would open the hypothesis of a cross-reactivity between non-aromatic and antimicrobial sulfonamides. It could be necessary an oral challenge test with furosemide in allergic patients to sulfamides.