Intradermal Tests With Drugs: An Approach to Standardization.

Background: Intradermal tests (IDTs) are performed and interpreted differently in drug allergy centers making valid comparison of results difficult. Objective: To reduce method-related and intercenter variability of IDTs by the introduction of a standardized method. Materials and methods: In 11 centers of the European Network for Drug Allergy, IDTs were prospectively performed with saline and with amoxicillin (20 mg/ml) using (1) the local method and (2) the standardized European Network in Drug Allergy (ENDA) method (0.02 ml). The diameters of the initial injection wheal (Wi) for the different volumes and sites injected obtained from each center were analyzed. Results: The most reproducible method was to fill a syringe with test solution, then expel the excess fluid to obtain exactly 0.02 ml. The median Wi diameter with 0.02 ml injection using the standardized method was 5 mm [range 2-10 mm; interquartile range (IQR) 5-5 mm; n = 1,096] for saline and 5 mm (range 2-9 mm; IQR = 4.5-5 mm; n = 240) for amoxicillin. IDT injection sites did not affect the Wi diameter. Training improved precision and reduced the variability of Wi diameters. Conclusion: Using the standardized IDT method described in this multicenter study helped to reduce variability, enabling more reliable comparison of results between individuals and centers.

Histopathological study of six types of adverse cutaneous drug reactions using granulysin expression.

BACKGROUND: Few studies have been published on the histopathology of cutaneous adverse drug reactions (CADR), and most of these lack information on skin allergological tests. The histopathology of drug reaction with eosinophilia and systemic symptoms (DRESS) is also seldom described. The purpose of our study was to examine six types of well-documented CADR (maculopapular exanthema, DRESS, fixed drug eruption, Stevens-Johnson syndrome, toxic epidermal necrolysis [TEN], and acute generalized exanthematous pustulosis) using histopathology and immunohistochemistry to evaluate the expression of granulysin, a key molecule in TEN. METHODS: We retrospectively included 106 skin biopsies performed in proven cases of CADR (by chronological investigation, single attributable drug, or/and skin tests). All slides were reviewed, and microscopic changes were analyzed using a standardized form. Granulysin expression was studied by immunohistochemistry. RESULTS: In DRESS, we observed spongiosis, edema, and basal vacuolization, with rare necrotic keratinocytes and constant lymphocytic infiltrate in the superficial dermis. Eosinophils were often present, and pustules were found in 15% of cases. Necrotic keratinocytes are often absent in maculopapular exanthema. Granulysin was expressed in six types of CADR with a trend toward more intense expression in DRESS and TEN. CONCLUSION: We detailed further about the histopathology of DRESS. Granulysin expression was observed in all CADR with a marked overlap of expression pattern between the six types.

Unexpected platelets elevation in a patient with idiopathic thrombocytopenia treated with oseltamivir for influenza infection.

Oseltamivir is a neuraminidase inhibitor approved for the prevention and treatment of influenza. Few haematological side effects have been reported with oseltamivir. We report herein the case of an unexpected platelet increase in a 46-year-old woman with idiopathic thrombocytopenia (ITP) treated with oseltamivir for influenza. The mechanism may involve the neuraminidase inhibition which decrease platelet surface sialic acid content and reduce their removal by the reticuloendothelial system. Oseltamivir may be responsible for platelet increase especially in patients with ITP.