Cutaneous and systemic manifestations of mastocytosis.
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Mastocytosis is characterized by an excessive number of apparently normal mast cells in the skin and, occasionally, in other organs. Characteristic skin lesions, called urticaria pigmentosa, are present in most patients, but clinical presentation can vary from a pruritic rash to unexplained collapse and sudden death. These lesions are typically tan to red-brown macules that appear on the trunk and spread symmetrically. Patients with mastocytosis often have a long history of chronic and acute symptoms that were unrecognized as mastocytosis. Skin lesions may or may not accompany systemic mastocytosis. Systemic disease may involve the gastrointestinal tract, the bone marrow or other organs. Even when the disease is considered as a possibility by the physician, the diagnosis can be difficult because of special technical requirements necessary for biopsy and because of the problems with biochemical testing. Drug therapy is initiated to stabilize mast cell membranes, to reduce the severity of the attacks and to block the action of inflammatory mediators. The mainstay of therapy is histamine H1 and H2 blockers and the avoidance of triggering factors. (+info)
Increased formation of thromboxane in vivo in humans with mastocytosis.
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Clinical manifestations of mastocytosis are mediated, at least in part, by release of the mast cell mediators histamine and prostaglandin D2. It has been previously reported that in addition to prostaglandin D2, mast cells produce other eicosanoids, including thromboxane. Nonetheless, little information exists regarding the formation of other prostanoids in vivo. The most accurate method to examine the systemic production of eicosanoids in vivo is the quantitation of urinary metabolites. We previously developed a highly accurate assay employing mass spectrometry to measure a major urinary metabolite of thromboxane, 11-dehydro-thromboxane B2, in humans. We utilized this assay to quantitate thromboxane production in 17 patients with histologically proven mastocytosis. We report that thromboxane formation was significantly increased (>2 SD above the mean) in at least one urine sample from 65% of patients studied. Of these, 91% of patients with documented systemic involvement had elevated thromboxane generation. In addition, endogenous formation of thromboxane was highly correlated with the urinary excretion of the major urinary metabolite of prostaglandin D2 (r = 0.98) and Ntau-methylhistamine (r = 0.91), suggesting that the cellular source of increased thromboxane in vivo could be the mastocyte. Enhanced thromboxane formation in patients with this disorder is unlikely to be of platelet origin as other markers of platelet activation, platelet factor 4 and beta-thromboglobulin, were not increased in three patients with marked overproduction of thromboxane. Furthermore, the recovery of 11-dehydro-thromboxane B2 excretion in two patients after the administration of aspirin occurred significantly more rapidly than the recovery of platelet thromboxane generation. These studies, therefore, report that thromboxane production is significantly increased in the majority of patients with mastocytosis that we examined and provide the basis to elucidate the role of this eicosanoid in disorders of mast cell activation. (+info)
Association of the Q576R polymorphism in the interleukin-4 receptor alpha chain with indolent mastocytosis limited to the skin.
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Gain-of-function mutations in c-kit, which appear to contribute to mast cell hyperplasia, have been detected in both limited and aggressive forms of mastocytosis, suggesting that other mutations or polymorphisms may contribute to the clinical phenotype. Because addition of interleukin-4 (IL-4) to mast cell cultures is reported to induce apoptosis, the hypothesis was considered that individuals carrying the gain-of-function polymorphism Q576R in the cytoplasmic domain of the alpha-subunit of the IL-4 receptor (IL-4R) might be relatively resistant to the gain-of-function mutation in c-kit. To assess this possibility, 36 patients with either cutaneous or systemic mastocytosis were studied for association with the Q576R polymorphism. The Q576R polymorphism was found more frequently in those with disease limited to skin and who exhibited lower levels of surrogate disease markers. These data suggest that the Q576R IL-4R alpha- chain polymorphism may mitigate disease expression and confer a better prognosis in patients with mastocytosis. (Blood. 2001;98:880-882) (+info)
One-step detection of c-kit point mutations using peptide nucleic acid-mediated polymerase chain reaction clamping and hybridization probes.
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The prognostic significance of somatic activating codon 816 c-kit mutations in pediatric urticaria pigmentosa has not yet been established in detail. Detection of such mutations in archival paraffin-embedded biopsies is usually hampered by an abundance of surrounding normal cells. Here we describe a method for the selective amplification and specific detection of c-kit mutation Asp816-->Val in complete tissue sections cut from up to 24-year-old paraffin blocks. Peptide nucleic acid-mediated polymerase chain reaction clamping of the wild-type allele was combined with on-line mutation detection using oligonucleotide hybridization probes. In DNA extracted from HMC-1 cells heterozygously carrying the c-kit mutation Asp816-->Val, the one-tube assay allowed specific detection of this mutation in a more than 1000-fold excess of normal background DNA within 1 hour and without the need for additional analytical steps. In a series of 38 cases with pediatric urticaria pigmentosa we detected c-kit codons 815 and 816 mutations in 16 cases. Mutation detection did not correlate with clinical outcome after a mean follow-up of 11.2 years. In conclusion, the procedure described may represent an ideal screening tool for all kinds of clinical applications, using point mutations as markers of, for example, early events in carcinogenesis, circulating metastatic tumor cells, and minimal residual disease. (+info)
Gastrointestinal involvement in systemic mastocytosis.
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Four consecutive patients with systemic mastocytosis were studied. One patient had a malabsorption syndrome with only minor histological changes of the intestinal mucosa. Another patient with ulcer diathesis had a gastric secretory pattern resembling Zollinger-Ellison syndrome. Serum gastrin and histamine levels were consistently normal in all patients. Endoscopy of stomach and colon disclosed urticaria-like papulae either spontaneously or after topical provocation in all patients. No increase of mast cells was found in multiple mucosal biopsies. A markedly increased gastric tissue content of histamine was found, however, in the three patients studied. The findings suggest that urticaria-like lesions associated with a high tissue content of histamine may be more important that hyperhistaminaemia in causing the various gastrointestinal symptoms. (+info)
CURRENT CONCEPTS IN DERMATOLOGY. II. THE SKIN AND SYSTEMIC DISEASE.
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Many systemic diseases have cutaneous manifestations. In some diseases skin involvement is the predominant factor (Behcet's syndrome, urticaria pigmentosa, discoid lupus erythematosus and pseudoxanthoma elasticum); in others the skin manifestations, when present, are an important part of the condition (sarcoidosis, systemic lupus erythematosus, hypersensitivity angiitis, porphyria). This report includes descriptions of and comments on these cutaneous manifestations. Erythema nodosum and erythema multiforme are reaction patterns of the skin and mucous membrane which may have many causes. The relationship between discoid and systemic lupus erythematosus is discussed. There is little doubt that these are variations of the same basic disease process, even though the prognoses are very different. (+info)
A study on cercarial dermatitis in Khuzestan province, south western Iran.
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BACKGROUND: Cercarial dermatitis' or swimmer's itch' is an itchy inflammatory response to the penetration of the skin by non-human schistosome parasites. In the hot season, (May to September) in Khuzestan province in the south west of Iran, swimming in canals and agriculture activities in swampy areas are common. This survey was made on people from villages north of Ahwaz city in south west Iran, to estimate cercarial dermatitis in this region. METHODS: 2000 people were observed for clinical signs of cercarial dermatitis. Also 2000 Lymnaea gedrosiana snails were collected from agriculture canals and examined for animal schistosome cercariae during 1998-2000. RESULTS: From this survey 1.1% of people had pruritic maculopapular rash on their feet, hands or other parts of body. From the total of examined snails, 2.4% were found to be infected with bird schistosome cercariae including Trichobilharzia species. CONCLUSION: Cercarial dermatitis could be a health problem in this area. This is the first report of cercarial dermatitis from this region of Iran. (+info)
Solitary mastocytoma causing recurrent blistering in infancy.
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Two children with solitary mastocytoma in infancy, both of whom had recurrently blistering scalp lesions, are reported in order to emphasise the diagnostic importance of this distinctive history. (+info)