Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Itch sensation is reduced by cooling the skin. We tested whether lowering skin temperature attenuates responses of spinal dorsal horn neurons elicited by intracutaneous (i.c.) microinjection of histamine in anesthetized rats. Cooling the skin to 3 degrees C significantly and reproducibly reduced (to a mean of 48%) i.c. histamine-evoked responses in 20 of 24 wide dynamic range-type dorsal horn neurons. Histamine-evoked responses recovered to control levels after rewarming the skin. Assuming that such neurons play a role in signaling itch, depression of their responses during skin cooling may account for the psychophysical observation that skin cooling relieves itch in humans.
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PMID:Skin cooling attenuates rat dorsal horn neuronal responses to intracutaneous histamine. 992 64

Antihistamines are the pharmacologic cornerstone of treatment for allergic rhinitis. The comparative effects of the newer, more specific H (1) -antagonists cetirizine and loratadine among younger patients are not well characterized. The efficacy and safety of cetirizine and loratadine were compared in a prospective, randomized, double-blind, longitudinal, parallel-group study of 80 children, 2 to 6 years of age, with perennial allergic rhinitis caused by house dust mites or plant pollens (verified by a radioallergosorbent or skin test). Patients received cetirizine or loratadine at 0.2 mg/kg once daily in the morning for 28 days. Histamine skin tests and eosinophil counts from nasal smears were performed at baseline and at the end of treatment. Individual rhinitis symptoms were assessed by the investigator at baseline and on day 28 and by parents at baseline and daily in symptom diaries. Global assessments were made by using a visual analog scale at baseline and at the end of treatment. Cetirizine produced significantly greater inhibition of the wheal response compared with loratadine (P <.0001). Eosinophil counts were improved to a comparable degree with both agents. Cetirizine and loratadine produced comparable improvements in symptoms and according to a global evaluation as assessed by the investigator at the end of treatment. Both agents produced substantial symptomatic relief according to patients' daily diary assessments; however, cetirizine was more effective than loratadine in relieving the symptoms of rhinorrhea, sneezing, nasal obstruction, and nasal pruritus (P <. 0001). Both treatments were well tolerated; two patients receiving cetirizine were dropped from the study because of adverse events. Cetirizine and loratadine provided effective, well-tolerated relief of the symptoms of perennial allergic rhinitis in small children. Cetirizine was more effective than loratadine in inhibiting the wheal response to histamine challenge and afforded greater reductions in most individual symptoms assessed daily by the parent.
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PMID:Double-blind comparison of cetirizine and loratadine in children ages 2 to 6 years with perennial allergic rhinitis. 1042 57

The purpose of this study was to evaluate the clinical efficacy over a period of three years (1988-90) of two preseasonal dosage regimens of a Parietaria allergoid (Bencard Tyrosine Parietaria) in patients who were only sensitive to this pollen. Fifty patients were included (14 men and 36 women, age: mean, 28 years; range, 14-47 years). Twenty five patients (group A) were treated each january with the basic course of Bencard Tyrosine Parietaria. This consisted of injecting subcutaneously 0.5 ml from each of three vials, with one week between each injection. A further injection using the vial with the highest dose was given one week later. Each january and february, twenty five patients (group B) were treated with the basic course of Bencard Tyrosine Parietaria, repeating the last dose five times, with one week between each injection. Immunotherapy with a tyrosine-adsorbed Parietaria judaica allergoid is an effective method for mitigating nasal (p < 0.0001), bronchial (p < 0.005), conjunctival (p < 0.001) and palatal itching symptoms (p < 0.0001) in patients who are sensitive to this pollen. Sensitivity to Parietaria pollen, as verified by skin test and nasal challenge, decreased during immunotherapy (p < 0.001). Histamine release by peripheral blood basophils decreased during the course of the study, falling from 43.5 ng/ml to 12.3 ng/ml in group A and from 42.9 ng/ml to 10.0 ng/ml in group B; during the second and third years, IgG levels were increased one and four months after starting treatment with the extract, while this was not the case after ten months; IgE levels were also increased. Finally, overall tolerance to this immunotherapy product was good in almost all patients.
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PMID:Comparison of the efficacy and safety of two preseasonal regimens of glutaraldehyde modified, tyrosine-adsorbed parietaria pollen extract over a period of three years in monosensitive patients. 1043 Nov 1

Histamine is present in the epidermis in intracellular and extracellular area and is released from mast cells and keratinocytes in the early stage of inflammation of the skin. Such release may contribute to common itching or intensify the inflammatory responses. Histamine binds to its receptors and participate in regulation of the inflammatory responses by acting on endothelial cells, nerve endings, lymphocytes, monocytes, and leukocytes. Histamine has direct effects on keratinocytes as well. Histamine modulates the proliferation of keratinocytes. The binding of histamine to the receptor on keratinocyte membrane induces activation of adenylate cyclase and phospholipase C through GTP binding protein. We previously reported that histamine induces transient increase in intracellular Ca2+ in cultured normal human epidermal keratinocytes (NHEK) and normal epidermis. H1 and H2 histamine receptors are widely distributed in many tissues and cells. In this study, we investigated which types of histamine receptors are related to the increase in intracellular Ca2+ by histamine stimulation in cultured human epidermal keratinocytes. NHEK were cultured in serum-free KGM medium. With H1 antihistamines, mepyramine and diphenhydramine, histamine responses were moderately but not statistically significantly inhibited. With H2 antihistamine, cimetidine, histamine response was significantly inhibited. Epinephrine response was not affected by these antihistamines. Thus, it is considered that H2 antihistamines specifically block histamine-mediated increase in intracellular Ca2+ of cultured normal human keratinocytes.
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PMID:H2 histamine receptor-mediated increase in intracellular Ca2+ in cultured human keratinocytes. 1051 81

Pain reduces itch-a commonly known effect of scratching the skin. Experimentally produced itch from histamine is sometimes accompanied by secondary sensations of pain. The present study investigated the effects of eliminating this pain, by means of a local anesthetic, on the itch and the enhanced mechanically evoked itch and pain that occur after an intradermal injection of histamine. In ten human subjects, the volar forearm was injected with either 20 microl of 2% chloroprocaine (experimental arm), or 20 microl of saline (control arm). Histamine 10 microl was injected into each bleb, and the resulting magnitude of itch estimated. The borders of three cutaneous areas were mapped within which mechanical stimulation of the skin surrounding the bleb elicited abnormal sensations (dysesthesiae): alloknesis, defined as itch evoked by innocuous stroking, and hyperalgesia and hyperknesis, characterized, respectively, by enhanced pain and enhanced itch evoked by pricking the skin with a fine tipped filament. The magnitude and duration of itch were significantly greater and the areas of dysesthesia significantly larger for the experimental than for the control arm. It is hypothesized that there exist two classes of histamine-sensitive primary afferent neurons. One class is "pruritic", and mediates itch whereas the other is "antipruritic", and evokes a centrally mediated reduction in histamine-evoked itch and dysesthesiae. It is further suggested that the anesthetic blocked the discharges of the antipruritic afferents, preventing the central inhibition from occurring and thereby unmasking the effects of the pruritic afferents.
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PMID:Enhancement of experimental pruritus and mechanically evoked dysesthesiae with local anesthesia. 1063 26

We investigated the effects of tactile allodynia on the itch and mechanically evoked dysesthesiae produced by an intradermal injection of histamine in human volunteers. After an intradermal injection of capsaicin into the volar surface of one forearm, there developed an area of tactile allodynia to stroking and hyperalgesia to pricking the skin. Histamine was then injected simultaneously into the area of allodynia (experimental arm) and into the opposite forearm (control arm). Magnitude estimates of itch were obtained every 15 s for 5 min, and the areas of cutaneous hyperalgesia (pricking-evoked pain), alloknesis (stroking-evoked itch), hyperknesis (pricking-evoked itch) and wheal and flare were measured. The areas of wheal and flare were not significantly different on the two arms. The magnitude of itch and the areas of hyperknesis and alloknesis developed normally on the control arm but were absent or greatly reduced on the experimental arm. Thus, both the itch and the alloknesis and hyperknesis normally induced by histamine were absent or greatly reduced when histamine was injected in an area of capsaicin-induced allodynia. These results are compatible with the hypothesis that activity in capsaicin-sensitive, nociceptive primary afferent neurons evokes a central neuronal inhibitory process that prevents or reduces the itch and mechanically evoked dysesthesiae normally produced by an intradermal injection of histamine.
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PMID:Attenuation of experimental pruritus and mechanically evoked dysesthesiae in an area of cutaneous allodynia. 1063 27

Histamine-induced food intolerance is not IgE-mediated. Skin-prick testing and specific IgE to food allergens are typically negative. Food rich in histamine or red wine may cause allergy-like symptoms such as sneezing, flush, skin itching, diarrhoea and even shortness of breath. The suspected reason is a diminished histamine degradation based on a deficiency of diamine oxidase. As diamine oxidase cannot be supplemented, a histamine-free diet was implemented to reduce histamine intake. Forty-five patients with a history of suffering from intolerance to food or wine (n = 17) and chronic headache (n = 28) were put on the diet over months to years. Fish, cheese, hard cured sausages, pickled cabbage and alcoholic beverages had to be avoided. Complaint intensity and drug-use per week prior to and 4 weeks after a histamine-free diet were compared. After 4 weeks on the diet 33/45 patients improved considerably (P < 0.01), eight of them had total remission. In 12/45 patients, however, no changes in symptoms were observed. Symptoms of food or wine intolerance significantly decreased (P < 0.02; treatment of choice), headaches decreased in frequency (P < 0.001), duration and intensity. After eating histamine-rich food symptoms were reproducible and could be eliminated by anti-histamines in most patients. These data indicate the role of histamine in food and wine intolerance and that histamine-rich food causes a worsening of symptoms in patients suffering from chronic headaches. Results obtained support the hypothesis of a deficiency of diamine oxidase in patients with intolerance to food or wine.
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PMID:Histamine-free diet: treatment of choice for histamine-induced food intolerance and supporting treatment for chronic headaches. 1077 86

Histamine remains the main mediator released by both specific allergic and non-specific mast cell activation. Histamine is the classic mediator of itching, flare and redness. The effects of histamine in allergic conjunctivitis are mediated by H1-receptor activation on blood vessels and nociceptive nerves. Histamine effects may be prolonged and exaggerated since a defect in the histaminase enzymes has been recently demonstrated in VKC. The effects of histamine on conjunctival tissues may be more complex than those manifested by the simple symptom of itching. In fact, proinflammatory effects of histamine on conjunctival epithelial cells and fibroblasts have been demonstrated. Preliminary results showed that the H1 antagonist, emedastine, reduces significantly cytokine production from histamine-stimulated fibroblasts.
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PMID:Role of histamine in allergic conjunctivitis. 1105 44

To assess the itch-associated response of primary afferents innervating the murine skin in vivo, dose-response curves and time-courses for itch-scratching and cutaneous nerve firing responses to intradermal injections of pruritogens (histamine and serotonin) were compared in ICR and ddY mice. Serotonin increased the itch-scratch response and cutaneous nerve firing in either ICR or ddY mice. Histamine increased these two responses in ICR, but not ddY, mice. The dose-response curves and time-courses for serotonin- and histamine-induced nerve firing were similar to those for the itch-scratch response. The results suggest that cutaneous nerve firing evoked by peripherally given pruritogens includes the itch-associated response.
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PMID:Itch-associated responses of afferent nerve innervating the murine skin: different effects of histamine and serotonin in ICR and ddY mice. 1120 20

A 30-year-old man with atopic dermatitis had had erythema and itching of the hands after washing rice in water, though he had always eaten cooked rice without problems. Handling test with water used to wash regular rice was performed on abraded hands, and produced urticarial erythema after several minutes. Applications of water used to wash allergen-reduced rice were negative for urticarial reaction. Prick test with water used to wash regular rice was +++. However prick test reaction with water used to wash allergen-reduced rice was +. Histamine-release test of regular rice-washing water was grade 3 and that of allergen-reduced rice grade 1. In immunoblotting analysis with regular rice washing water, there were no bands with this patient. These results suggest that the allergen responsible for contact urticaria in this patient might be water-soluble, heat-unstable, and not contained in allergen-reduced rice.
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PMID:Contact urticaria from rice. 1120 11


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