Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042109 (urticaria)
 6,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Topical application of capsaicin is thought to deplete substance P from local sensory nerve terminals. In experiments on human skin inflammation was induced by injection of substance P (SP) or histamine intradermally, UV irradiation, non-immunologic contact urticaria, tuberculin reaction, contact allergens and benzalkonium chloride with or without capsaicin pretreatment. The flare response to SP and histamine was suppressed by capsaicin pretreatment whereas the wheal was enlarged. Interestingly, capsaicin pretreatment enhanced the responses to all other inflammatory agents.
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PMID:The effect of capsaicin on some experimental inflammations in human skin. 243 72

The prevalence of autoantibodies of immunoglobulin G (IgG) and immunoglobulin M (IgM) classes directed against myeloma immunoglobulin E (IgE) were determined in distinct subsets of urticaria, using an enzyme immunoassay. IgG anti-IgE antibodies were found in five of nine patients (55%) with cold urticaria, four of eight patients (50%) with urticarial vasculitis, and three of six patients (50%) with chronic urticaria. IgM anti-IgE antibodies were found exclusively in cold urticaria (two of nine patients, 22%). Heating of these sera increased the binding to IgE, suggesting immune complex formation. Several positive sera were capable of inducing histamine release from normal peripheral basophils and caused a wheal-flare response upon intradermal injection. Sera containing such autoantibodies from three cold urticaria patients were studied for passive transfer of cold sensitivity. One serum containing IgG anti-IgE gave a strongly positive transfer test at 5 h but not 48 h, suggesting a pathogenic role for the IgG.
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PMID:Prevalence and functional role of anti-IgE autoantibodies in urticarial syndromes. 244 92

Substance P (SP), calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP) were assayed in lesions and normal skin of patients with dermographism and cold urticaria utilizing suction-induced blisters. There was no difference in SP and VIP concentrations between challenged and control skin of urticaria patients. On the whole, however, the concentration of both neuropeptides, and VIP in particular, was higher in the urticaria patients than in control subjects. CGRP levels were not increased. SP and VIP in blood samples from veins draining challenged skin areas were below the detection limit. It is concluded that SP and VIP may potentiate histamine in wheal formation and thus contribute to the increased reactivity of the skin to trauma and temperature changes in patients with physical urticaria.
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PMID:Occurrence of substance P, vasoactive intestinal peptide, and calcitonin gene-related peptide in dermographism and cold urticaria. 244 38

A 17-year-old male with solar urticaria is described. The action spectrum ranged from 400 to 520 nm. Wheals induced by visible light were inhibited by simultaneous or subsequent irradiation of the skin with UVA radiation. UVA irradiation prior to exposure to eliciting wavelengths revealed no inhibitory effect, nor was an inhibitory effect found by pre- or postirradiation of test sites with visible light longer than 530 nm. In vitro activation of the patient's serum by exposure to visible light induced wheal formation at the injection site. The wheal formed by in vitro-activated serum was suppressed only when the serum was exposed to UVA after, but not before irradiation with wavelengths of the action spectrum. This suggests that the inactivation of a photoallergen rather than of its precursor is the mechanism by which UVA exerts an inhibitory effect.
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PMID:Solar urticaria induced by visible light and inhibited by UVA. 246 80

Multiple sequential biopsy specimens of wheals elicited by a solar simulator in four patients with severe solar urticaria were studied with the use of indirect immunofluorescence for eosinophil granule major basic protein. Examination of control biopsy specimens from normal, unstimulated skin did not show eosinophils or major basic protein deposition. Five minutes after solar simulation, eosinophils were observed in vessels in the dermis, and 2 hours later there was marked tissue eosinophilia. Extracellular major basic protein was extensively deposited in the dermis at 2 and 24 hours, suggesting eosinophil degranulation. Thus evolution of the solar urticaria wheal is accompanied by infiltration of eosinophils and neutrophils and by tissue deposition of the eosinophil major basic protein, suggesting eosinophil degranulation.
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PMID:Evidence for eosinophil degranulation with deposition of granule major basic protein in solar urticaria. 208 77

Loratadine is an addition to the class of nonsedating antihistamines which includes terfenadine, astemizole, and acrivastine. Loratadine is chemically related to the tricyclic antidepressants. Animal data have shown that insignificant amounts of loratadine enter the brain, and it has a threefold greater affinity for peripheral as compared with central histamine 1-receptors. Loratadine has one main metabolite, descarbethoxyloratadine, which is four times more active than the parent drug. Loratadine reaches peak plasma concentration in 1-2 hours; the metabolite does so in 3-4 hours. Their respective elimination half-lives are about 10 and 20 hours. Onset of action is within 1 hour and duration is at least 24 hours. Once-daily dosing is recommended. Generally, loratadine is as efficacious as existing antihistamines in relieving symptoms of allergic rhinitis, urticaria, and in suppressing wheal formation. Reports of sedation and other adverse reactions are no more frequent than found with placebo. Tachyphylaxis has not been noted in humans, and there is minimal potential for drug interactions based on animal data. Loratadine and terfenadine have comparable therapeutic applications. Both have shown minimal adverse effects, but loratadine has a quicker onset and longer duration of action. These two agents are useful for acute allergic reactions. In contrast, astemizole has an onset of action of several days and is most useful for prophylactic treatment of seasonal allergies.
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PMID:Loratadine: a nonsedating antihistamine with once-daily dosing. 252 47

The ability of drugs to inhibit histamine-induced wheals has been used frequently as a pharmacodynamic index of clinical efficacy. Host response using this model can be predictive of clinical response in atopic diseases such as allergic rhinitis and urticaria. Terfenadine is a widely used nonsedating antihistamine currently approved for use at a dosage of 60 mg every 12 hours. Our clinical trial was designed to determine whether higher dosages of this agent were associated with amplified efficacy in suppressing the wheal response to intradermal histamine phosphate. Twenty-six healthy male Caucasian volunteers were randomized in a double-blind crossover fashion to receive terfenadine 60 mg every 12 hours, 120 mg each day, 120 mg every 12 hours, and placebo. Each dose was given orally for three days followed by a 6-day washout period. Histamine was administered intradermally one hour prior to dosing for baseline measurements. Histamine was given at defined intervals after treatment or placebo on days 1 (acute dosing) and 3 (steady state), and the percent inhibition of histamine-induced wheal area as compared with baseline was determined. Subjects receiving all three active doses exhibited significant wheal inhibition compared with placebo on days 1 and 3 (P less than or equal to .01). Subjects receiving the 60 mg every 12 hours and the 120 mg each day dosages exhibited roughly equivalent mean wheal suppression over the 24-hour period of each testing day (54% versus 60%, respectively, on day 1 and 62% versus 63%, respectively, on day 3, no significant differences).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of inhibition of wheal response to histamine by multiple doses of terfenadine. 257 53

This short review examines two examples of studies into the mechanisms of allergic responses which have particular relevance to inflammation research. The first is the ability of human skin mast cells, but not those derived from lung, adenoids, tonsils or intestine, to release histamine in response to stimulation by neuropeptides including substance P, vasoactive intestinal polypeptide (VIP) and somatostatin. The neuropeptide activation site does not appear to be a classical tachykinin receptor but rather a binding site of low affinity and low specificity capable of interacting with neuropeptides and compounds with similar physicochemical characteristics. In contrast to IgE-dependent activation, neuropeptide stimulation of skin mast cells induces a rapid release of histamine with minimal generation of PGD2 and LTC4. This pseudo-allergic reaction is thought to underlie the weal and flare response in the skin and may have a role in urticaria. The second example describes studies to elucidate the mechanisms of the late asthmatic response by use of a guinea-pig model. As in man, both early and late phase responses in the guinea-pig are inhibited by sodium cromoglycate whereas only the early response is inhibited by the beta-adrenoceptor stimulant drug salbutamol. Examination of bronchoalveolar fluid has shown a temporal relationship between an airways neutrophilia and the late response. However, pharmacological manipulation and the use of an anti-neutrophil serum has shown that these events are not interdependent. The role of the airways eosinophilia requires further investigation.
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PMID:Allergy or inflammation? From neuropeptide stimulation of human skin mast cells to studies on the mechanism of the late asthmatic response. 265 5

A controlled trial of 4-weeks oral photochemotherapy (PUVA) on 14 patients with severe symptomatic dermatographism produced a clinically useful reduction in itching in five patients. In four of these patients itching had relapsed to pre-treatment levels within 3 months of finishing the PUVA course. A comparison of the weal and flare responses on exposed and covered (control) skin using a calibrated dermographometer showed no significant change in skin reactivity, even in the patients who experienced symptomatic relief. While PUVA may temporarily reduce itching in some patients with symptomatic dermographism, its use cannot generally be justified for treating this type of physical urticaria.
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PMID:The effect of psoralen photochemotherapy (PUVA) on symptomatic dermographism. 268 Jan 76

The histopathology, immunofluorescence and ultrastructure of skin in idiopathic cold-contact urticaria have been studied over the 24 h following the application of a cold stimulus sufficient to provoke a confluent weal on the anterior thigh. Biopsies were taken 10 min, 2 h and 24 h after ice removal. Considerable epidermal and dermal oedema was present. Type I and Type II mast-cell degranulation was noted but was not universal. Lymphatics and capillaries were dilated and endothelial cells showed an increase in micropinocytotic activity, without evident vasculitis. In two cases packed platelets were seen within vessel lumina. There was no change in the infiltrating dermal cell population and direct immunofluorescence was negative. The evidence suggests that idiopathic cold-contact urticaria is an exudative rather than an infiltrative process.
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PMID:A timed study of the histopathology, direct immunofluorescence and ultrastructural findings in idiopathic cold-contact urticaria over a 24-h period. 269 Nov 33


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