A new occlusive patch test system comparable to IQ and Finn chambers.

Background: A good patch test system should have good adhesion and contact, and minimal leakage; Finn and IQ patch test system have these properties but are expensive. Aims: To develop a new cost‑effective occlusive patch test system that had good contact with the skin and was non‑irritant. Methods: The system (designated Chamber X) was fabricated using a semi‑permeable tape and a flexible virgin plastic chamber. Chamber X was developed by (i) selecting adhesive tape based on its non irritancy and adhesive potential (ii) testing plastic chamber material for its skin irritancy (iii) testing the assembled system against Finn, IQ and locally available chambers for irritancy, contact, leakage and occlusivity. Results: Chamber X showed better occlusion than IQ, Finn and locally available chambers and was comparable to, (P > 0.05) IQ and Finn in terms of irritancy, contact and leakage. Conclusions: The results demonstrate that the Chamber X offers a cost effective patch test system comparable to IQ and Finn chambers in terms of safety, adhesion, leakage and occlusivity.

Is the menstrual cycle affecting the skin prick test reactivity?

Allergen skin prick tests (SPT) are very sensitive and specific tests to detect allergic sensitization in atopic patients. Certain factors like antihistamines, antidepressant therapies or circadian rhythms can alter the results of SPT. In women, the changes in endogenous hormone levels throughout the menstrual cycle may affect the allergic responses and natural course of allergic diseases. The aim of this study was to investigate the probable influence of the phases of the menstrual cycle on SPT reactivity to allergen extracts and histamine. Forty-two female patients with seasonal allergic rhinoconjunctivitis were enrolled in the study. Skin prick test reactivities to allergens and histamine were measured at the beginning of the menstrual cycle (3rd or 4th day), mid-cycle (14th or 15th day) and end-cycle (27th or 28th day) consecutively. Serum estradiol, progesterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels were determined simultaneously. We observed the most significant reactions to allergens when SPT is performed at mid-cycle. However, SPT reactivity to histamine did not vary throughout the menstrual cycle. Serum estradiol and LH levels showed positive correlation with SPT reactivity to allergens at mid-cycle. Our results suggest that SPT give the best results when they are performed at mid-cycle. Additionally, allergens seem to cause mast cell degranulation to a greater extent in subjects in which endogenous hormones like estradiol and LH are elevated.

Major house dust mite allergen, Der p I, activates phospholipase D in human peripheral blood mononuclear cells from allergic patients: involvement of protein kinase C

The major house-dust-mite allergen, Der p I, stimulates the phospholipase D (PLD) in peripheral blood mononuclear cells (PBMC) from allergic patients with maximal responses after 30 min exposure. At 30 min, Der p I stimulated PLD activity by 1.4-fold in mild, 1.6-fold in moderate and 2-fold in severe allergic patients over control values (p < 0.05). When the cells were pretreated for 24 h with phorbol myristate acetate to down-regulate protein kinase C (PKC), PLD stimulation by Der p I was largely abolished. These results indicate that in PBMC from allergic patients, Der p I can stimulate PLD activity, and that PKC activation is involved in this stimulation.

Anafilaxia / Anaphilaxia

La anafilaxia sistémica resulta de la liberación de mediadores de una variedad de células inflamatorias. La mayoría de las reacciones son debidas a medicamentos, piquetes de insectos, alimentos, medios de radiocontraste, vacunas, sueros heterólogos, productos sanguíneos, hiposensibilización, etc. Es relativamente fácil su diagnóstico en la mayoría de los casos, con un cuadro clínico que puede ir desde simples lesiones en piel como urticaria hasta el compromiso cardiovascular y respiratorio que comprometa la vida. Como en todos los casos el manejo será encaminado a mantener las vías aéreas permeables y la homeostasis cardiovascular. La adrenalina constituye la primera línea terapéutica por sus acciones adrenérgicas, acompañadas con soluciones cristaloides o coloides para restaurar el volumen vascular, así como también con antihistamínicos y esteroides (para la fase tardía) de acuerdo a la intensidad del cuadro clínico. El manejo óptimo a largo plazo del paciente incluye la identificación del agente causal, la educación del paciente y de sus familiares para el empleo de la adrenalina en situaciones de exposición accidental que puedan desencadenar la muerte