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

Antihistamines are a diverse group of drugs which possess the ability to inhibit various histaminic actions. By and large, they bear a certain structural resemblance to histamine, and act principally to prevent histamine-receptor interaction through competition with histamine for histamine receptors. Consequently, they are helpful therapeutically in preventing, rather than reversing, histaminic actions. Individual antihistaminic drugs act to inhibit histaminic action at one or another histamine receptor (H1 or H2-receptor), but not at both receptors. The large number of antihistaminics which have been available for many years and employed chiefly as 'antiallergic' drugs are classified as H1-receptor inhibitors; they are most effective therapeutically in inhibiting manifestations of histamine-induced wheal and erythema formation and pruritus. H2-receptor inhibitors, agents which are able to inhibit histamine-induced gastric acid secretion, have been developed more recently. Antihistaminics in general and H1-receptor inhibitors in particular, exert a wide variety of pharmacological activities. Their use is frequently accompanied by undesirable side-effects, notably CNS depression, dryness of mucous membranes, and gastrointestinal effects. Used judiciously and in proper dosage, antihistaminic drugs are helpful in the control of allergic disorders, allergic rhinitis and urticaria in particular; newly developed H2-receptor inhibitors show therapeutic promise in the treatment of peptic ulceration.
 ...
PMID:Antihistamines: pharmacology and clinical use. 0 70

A dose-and-time related-effect of oral phenyltoloxamine citrate, a Class I, H1 antihistamine compound, has been demonstrated against allergen-induced wheal-and-erythema skin reactions among 10 adults with a diagnosis of allergic rhinitis and seasonal pollinosis. Clinical improvement in the existing symptoms of rhinorrhea, nasal obstruction, pruritus and sneezing, showed a significant correlation with the inhibition of reagin-mediated skin reactivity caused by phenytoloxamine. No adverse side effects were observed. It can be concluded that oral phenyltoloxamine citrate possesses antihistaminic properties and a range of safety which make it a useful agent for the symptomatic management of upper respiratory allergy.
 ...
PMID:Inhibition of cutaneous and mucosal allergy with phenyltoloxamine. 2 84

Intradermal injection of synthetic substance P (10(-7)--10(-5) M in humans produced flare, wheal and itching. These responses were inhibited by oral pretreatment of the subjects with an antihistaminic drug (chlorcyclizine) or by local pretreatment with Compound 48/80 administered to deplete the local stores of mast-cell bound histamine. The findings indicate that the responses induced by substance P were mainly mediated by histamine released from the dermal mast cells. In contrast to previously studied histamine liberators, substance P was less potent when acting on rat mast cells in vitro than on human skin mast cells in vivo. When incubated with rat peritoneal mast cells, about 100 times higher concentrations (10(-5) M) were required to induce histamine release than in the in vivo studies on humans. It was concluded that substance P is a potent histamine liberator in human skin.
 ...
PMID:Flare and itch induced by substance P in human skin. 8 Dec 43

The effects of intradermally administered histamine H1- and H2-receptor antagonists on the cutaneous responses--redness, weal, flare and itch--induced by intradermal injection of histamine were studied in man. Weal and redness were studied after blockade of the axon reflex by local infiltration with lidocaine. All responses were significantly inhibited by the H1-receptor antagonist mepyramine. The H2-antagonists cimetidine and metiamide reduced flare and itch significantly but not to the same extenet as mepyramine and not in a clearly dose-related manner. The size of weal and redness was not significantly reduced by cimetidine. No further reduction of flare, itch or weal was obtained by adding metiamide or cimetidine to mepyramine. After blockade of the axon reflex with lidocaine the histamine-induced weals turned white at the centre. This blanching was more prominent when histamine was injected in combination with cimetidine. Substituting mepyramine for cimetidine resulted in small weals with an intense red colour. It is concluded that, apart from being engaged in the direct vasodilatory response to histamine, H2-receptors do not seem to be involved in the other cutaneous responses to histamine studied.
 ...
PMID:Effects of histamine receptor antagonists on histamine-induced responses in human skin. 9 42

In ten patients suffering from symptomatic dermographism the combined administration of chlorpheniramine + cimetidine produced a greater reduction in the weal and flare response provoked by a standardized scratch than the administration of chlorpheniramine alone. There was a statistically significant improvement in the overall assessment of the patient's skin condition with the combined administration of chlorpheniramine + cimetidine. Chlorpheniramine given alone produced no significant benefit whilst cimetidine alone produced a marked exacerbation in itching in nearly half the patients who initially entered the study and was sufficient to require withdrawal.
 ...
PMID:The effect of H1 and H2 histamine antagonists on symptomatic dermographism. 47 88

Fleas are small, reddish-brown, wingless insects with a laterally compressed body and a pronounced third pair of legs adapted to leaping. Of the 100 species found in Middle Europe, hardly a dozen are of medical importance, they concern mainly people in contact with domestic animals. The cat flea, Ctenocephalides felis felis, and the bird flea. Ceratophyllus gallinae, are the most important human-pathogenic species in our region. A flea bite shows first as a haemorrhagic punctum, accompanied by itching, and leads to an erythema with or without central wheal. After 12--24 hours a papule appears which persists up to 2 weeks. Linimentum zinci with 10% Neocid alleviates the itching and prevents further infestation. The fleas are destroyed in their hiding places and on their animal host by applying Toxical-, Neocid- or Noflo-powder. The tropical sand flea, Tunga penetrans, is a permanent ectoparasite of man. It is seen in people returning from the tropics. Fleas may, even in our region, be vectors of bacteria, viruses, rickettsiae and intestinal parasites.
 ...
PMID:[Siphonaptera/fleas (author's transl)]. 49 45

IgE antibodies are usually thought to induce only immediate skin reactions. We have shown that the intradermal injection of a number of different allergens can produce a prolonged inflammatory reaction after the immediate wheal and flare in most sensitive subjects. This late inflammatory response occurs 6-12 h after challenge and is characterized by diffuse edema, erythema, pruritus, and heat. Both immediate and late responses can also be seen after passive sensitization of skin sites in nonatopic subjects. That IgE is involved in inducing the reaction was shown by the abolition of both immediate and late responses by passive transfer tests in the following experiments: (a) heating atopic serum at 56degreesC for 4 h, (b) removing IgE from the atopic serum by a solid phase anti-IgE immunoabsorbent, and (c) competitively inhibiting the binding of IgE antibodies to cells by an IgE myeloma protein. In addition, both responses were induced by affinity chromatography-purified IgE antibody, followed by antigenic challenge. Very similar lesions could also be induced by intradermal injection of Compound 48/80, thus suggesting a central role in the reaction for the mast cell or basophil. Histologically, the late phase is characterized by edema and a mixed cellular infiltration, predominantly lymphocytic but also containing eosinophils, neutrophils and basophils. Direct immunofluorescent staining did not show deposition of immunoglobulins or complement components, except IgM in 2 of 15 and C3 in 1 of 15 patients. This finding indicates that the late phase does not depend on the deposition of immune complexes. The results of the study suggest that IgE-allergen interaction on the surfaces of mast cells or on infiltrating basophils causes both immediate and late cutaneous responses.
 ...
PMID:The late phase of the immediate wheal and flare skin reaction. Its dependence upon IgE antibodies. 78 99

Morphological changes in cutaneous nerve endings were investigated electron microscopically in patients suffering from certain kinds of urticaria with associated itching and in normal skin in which wheals and local itching were induced either by application of nettle hairs or by intracutaneous injections of a timothy pollen extract. Skin samples were obtained with a high speed dermal punch without anesthesia from the wheal areas. It was found that some subepidermal free nerve endings derived from non-myelinated nerve fibers (penicillate endings) showed accumulations of extra-cytoplasmic glycogen which was localized in the distended spaces between the axolemma, the Schwann cell membrane and the nerve basement membrane. In some cases, the glycogen was found to be so abundant that it occupied most of the cross sectional area of the ending. No morphological changes were observed in the pappilary endings, in nerve endings of the hairs or in the autonomic terminals. The conducting segments of all cutaneous nerve fibers showed normal morphology. The unusual morphological changes that occur in some penicillate nerve endings during the wheal development indicate that these endings are involved in the skin reaction and therefore they may be the specific end organs that are associated with itch, at least in urticaria.
 ...
PMID:Fine morphological changes in the penicillate nerve endings of human hairy skin during prolonged itching. 86 27

Ammonium persulfate is widely used to "boost" peroxide hair bleaches. These persulfates can produce a variety of cutaneous and respiratory responses, including allergic eczematous contact dermatitis, irritant dermatitis, localized edema, generalized urticaria, rhinitis, asthma, and syncope. Some of these reactions appear to be truly allergic while others appear to be due to the release of histamine on a nonallergic basis. Patch tests may be performed with 2% to 5% aqueous solution of ammonium persulfate. Scratch tests may result in asthma and syncope. In some patients, merely rubbing a saturated solution of ammonium persulfate into the skin will evoke a large urticarial wheal. Hairdressers should be made aware that these ammonium persulfate hair bleach preparations may provoke severe reactions and should seek medical attention if the client complains of severe itching, tingling, a burning sensation, hives, dizziness, or weakness.
 ...
PMID:Persulfate hair bleach reactions. Cutaneous and respiratory manifestations. 96 35

In a series of 136 cases of hydatid disease affecting various tissues and organs admitted to one surgical unit in the Medical City Hospital, Baghdad, and personally studied and treated by the author, the liver was involved in 94 cases (69-1 per cent) and intrabiliary rupture occurred in 15. Pain in the right upper abdominal quadrant associated with tenderness and rigidity, radiating to the back and right, shoulder, was the presenting feature in almost all the patients. Hectic fever was present in 14. Obstructive jaundice developed in all the patients at some stage of the illness, but was complete with clay-coloured stools in only half. Chills and rigors were present in 67 per cent, eosinophilia in 40 per cent, a positive Casoni's test in 87 per cent, itching with urticaria and weal formation in 20 per cent and a palpable mass in the liver in 67 per cent of cases. Operative treatment is mandatory in order to clean the mother cyst of hydatid membranes, debris and daughter cysts, to explore and clear the common bile duct and to ensure free biliary passage to the duodenum. Sphincterotomy is neither necessary nor advisable, and when the gallbladder is not invaded by the cyst it should be preserved.
 ...
PMID:Intrabiliary rupture of hydatid cyst of the liver. 119 49


1 2 3 4 5 6 7 8 9 10 Next >>