Wheal flare

Clough GF, Boutsiouki P, Church MK Comparison 57 of the effects of levocetirizine and loratadine on histamine-induced wheal, flare, and itch in human skin. Allergy 2001 56 985-988. 58... 

Development of erythema, wheal, flare, or eruption indicates procaine sensitivity treat by the usual methods. 

Grant JA, Riethuisen JM, Moulaert B, DeVos C A double-blind, randomized, single-dose, crossover comparison of levocetirizine with ebastine, fexofenadine, loratadine, mizolastine, and placebo sup- 59 pression of histamine-induced wheal-and-flare response during 24 hours in healthy male subjects. 

The older test is the pin prick test where a small quantity of the antigen is placed under the skin. If there is an allergic reaction a wheal and flare, i.e. a hive, will appear. The pin prick test is not suitable for those who undergo anaphylactic shock. 

Symptom relief is caused in part by anticholinergic properties, which are responsible for the drying effect that reduces nasal, salivary, and lacrimal gland hypersecretion. Antihistamines antagonize increased capillary permeability, wheal-and-flare formation, and itching. 

Obsewe and record skin wheal-and-flare response. 

The anti-inflammatory agent benzoxaprofen (229) was withdrawn from clinical use in 1982 because of its photosensitizing effects [83]. Many patients experienced itching and urticaria, while some suffered onycholysis - separation of the finger nails from the nail beds [138], In a trial, healthy volunteers were sensitive by the 4th day of treatment. UVA provoked itching and a burning sensation followed by development of a classical wheal and flare response within 2 to 4 min [139]. 

In humans, the intradermal injection of SP (10 7-10 5 M) produces a flare, wheal and itching, and these effects are prevented by pretreatment with chlorcyclizine (an antihistamine) or by local pretreatment with compound 48/80 [ 103, 104]. It causes histamine release from sections of human foreskin [105]. These authors suggested that SP is significantly less active on isolated rat peritoneal mast cells than in human skin. 

Dynorphin, a-neoendorphin and /1-endorphin each produced a dose-dependent (10 6 M to 10 4 M) release of histamine from rat peritoneal mast cells but not from rat mucosal mast cells which were isolated following collagenase digestion [128]. When administered intradermally to the forearms of human volunteers, dynorphin, /f-endorphin, Leu-enkephalin and morphiceptin each produced a wheal and flare reaction at nM concentrations. Mast cell degranulation was confirmed by electron microscopy of biopsy samples and by its inhibition by hyroxyzine pretreatment [129]. 

Cetrizine The PK-PD modeling characterized the time course of cetirizine effect on histamine-induced skin reactions (wheal and flare). The histamine-induced flare was at least 80% inhibited at the start of the second administration. Thereafter, on successive administrations, the inhibition was even more pronounced and the response control was nearly total... 

Richardson and colleagues [3] identified a simple in vivo assay for the 5-HT3 receptor in man. They showed that the application of 5-HT to the exposed base of a blister evokes a pain and a wheal and flare response. These can be blocked by 5-HT3 receptor antagonists. Obviously one needs willing volunteers for such studies and suitable safety data must be available, but this is a useful model for assessing 5-HT3 receptor antagonist activity in man. 

Antagonism of Skin wheal and flare to i.d. histamine Hi antagonist... 

In addition to the flush, wheal, and flare, transient pain and itching result from the effects of histamine on sensory nerve endings. In sensitized individuals, intra-dermal injection of specific antigens produces a wheal this reaction is the basis for a skin test to quantify the extent of the allergic response. 

Ambiguous response Wheal being only slightly larger than initial injection bleb, with or without accompanying erythematous flare and larger than the control site... 

Fexofenadine inhibited antigen-induced bronchospasm and histamine release from mast cells. No anticholinergic or alpha adrenergic-receptor blocking effects were observed. Moreover, no sedative or other CNS effects were observed. Fexofenadine does not cross the blood-brain barrier. It inhibits skin wheal and flare responses produced by histamine injection. Following single and twice daily oral administration, antihistaminic effects occurred within 1 hour, achieved a maximum at 2-3 hours, and lasted a minimum of 12 hours. 

Fruit juices such as grapefruit, orange, and apple may reduce the bioavailability and exposure of fexofenadine. This is based on the results from three clinical studies using histamine-induced skin wheals and flares coupled with population pharmacokinetic analysis. Therefore, to maximize the effects of fexofenadine, it is recommended that ALLEGRA-D 24 HOUR should be taken with water... 

Intradermal injection of histamine causes a characteristic red spot, edema, and flare response that was first described many years ago. The effect involves three separate cell types smooth muscle in the microcirculation, capillary or venular endothelium, and sensory nerve endings. At the site of injection, a reddening appears owing to dilation of small vessels, followed soon by an edematous wheal at the injection site and a red irregular flare surrounding the wheal. The flare is said to be caused by an axon reflex. A sensation of itching may accompany these effects. 

The classical example of immediate hypersensitivity in humans is the wheal and flare reaction. Challenging a sensitized individual with an intradermal injection of... 

Solley GO, Gleich GJ, Jordon RE, Schroeter AL. 1976. The late phase of the immediate wheal and flare skin reaction. Its dependence upon IgE antibodies. J Clin Inv. 58 408 120. 

A 45-year-old man with type 2 diabetes treated with glibenclamide and metformin received combined chemotherapy for non-Hodgkin s lymphoma and was given premixed insulin. He developed local wheal-and-flare reactions immediately after the injections. Skin prick tests were positive for various types of insulin but weakly positive for lispro and negative for insulin aspart. He tolerated aspart insulin without any allergic reactions. 

A 4-week, single-blind, randomized, parallel-groups, dose-response study was conducted to test botanicals for allergy as measured by a skin patch test (wheal-and-flare reaction). The study was approved by an independent review board, informed consent was obtained before any screening or study measures, and the study was... 

The allergens produced wheals 4-8 mm in diameter. Flares were not measured because of inconsistent appearance (some subjects had no flares, but all subjects had some wheal reaction). The wheal was measured by adhesive tape applied to the forearm, which when removed retained the outline of the wheal. The longest and shortest wheal diameters were averaged and these values were used to compare allergen reaction before and after treatment with the various botanicals and doses. 

The use of Dimethyl sulphoxide (DMSO) in dermatology has a long history.18,19 In concentrations up to 50% DMSO is used for topical treatment of amyloidosis,20 but in concentrations of 90% and higher it is known to induce whealing and a flare reaction. The procedure described here is a modification of that described by Frosch et al.21 for the identification of individuals with sensitive skin. The DMSO reaction can be assessed clinically or measured with the laser Doppler flowmeter.22 The recent development of laser Doppler imagers28 make it possible to measure the DMSO induced increase in blood flow with unparalleled accuracy. To elicit the reaction 15 /ul of 90%, 95%, and 100% DMSO were applied to three adjacent sites and immediately covered with a circular plastic disc,... 

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