A. Kobza Black

Leukotriene B4-like material in scale of psoriatic skin lesions

1 Acidic lipid extracts of scale from the lesions of the skin disease, psoriasis, were purified by straight phase high performance liquid chromatography (h.p.l.c). Assay of fractions by an agarose microdroplet chemokinesis method showed the presence of biologically active material that co‐eluted with standard leukotriene B4 (LTB4). 2 LTB4‐like chemokinetic activity was also detected in fractions collected on reversed phase h.p.l.c. of psoriatic scale extracts that were initially purified by straight phase h.p.l.c. 3 No LTB4‐like activity was detected after similar purification of scale obtained by abrasion of large areas of normal skin. 4 The LTB4‐like material found in extracts of psoriatic scale may play a role in the pathogenesis of the neutrophil infiltrate which characterizes psoriasis.

A new method for recovery of exudates from normal and inflamed human skin

A new method for recovery of exudate from human skin using a suction bulla technique is described. Undiluted exudate was obtained with minimal trauma and analysed for histamine, kinin and prostaglandin (PG)‐like activity, by superfusion cascade bioassay. The PG‐like activity was further characterized by gel partition, gas–liquid and thin‐layer chromatography. PGE2 and PGF2α were further characterized by gas chromatography–mass spectrometry (GC–MS) and PGF2α by radioimmunoassay. Histamine was detected as was kinin‐like activity. Prostaglandins E2 and F2α with their metabolites, were also detected.

Aquagenic urticaria: evidence of cholinergic and histaminergic basis

Two patients with urticaria evoked at the site of contact of skin with water have been studied. Protection of the skin from contact with water by prior application of petrolatum ointment prevented wealing, but removal of the stratum corneum enhanced wealing.

Contact urticaria due to the common stinging nettle (Urtica dioica)--histological, ultrastructural and pharmacological studies.

A frequent cause of contact urticaria is skin exposure to the common stinging nettle (Urtica dioica). The urticaria is accompanied by a stinging sensation lasting longer than 12 h. Little is known of the cellular and molecular mechanism of stinging‐nettle urticaria. After preliminary pharmacological analysis of pro‐inflammatory activity in nettle stings, the cellular response of mononuclear cells, polymorphonuclear cells and mast cells was examined in six people 5 min and 12 h after nettle contact. Only mast cell numbers were significantly increased at 12 h. Ultrastructurally, some mast cells showed evidence of degranulation at 5 min and 12 h. At 12 h mast cells were closely associated with dermal dendritic cells and lymphocytes suggesting a functional unit. The mean histamine and serotonin contents of a nettle hair were found to be 6.1 ng and 33.25 pg, respectively. Nettle‐sting extracts did not demonstrate histamine release from dispersed rat mast cells in vitro. These results suggest that part of the immediate reaction to nettle stings is due to histamine introduced by the nettle. However, the persistence of the stinging sensation might suggest the presence of substances in nettle fluid directly toxic to nerves or capable of secondary release of other mediators.

Release of prostaglandin D2 and histamine in a case of localized heat urticaria, and effect of treatments

A case of localized heat urticaria in a 70‐year‐old woman is reported. Increased plasma levels of prostaglandin D2 and blood histamine after heat challenge indicate a role for mast cell degranulation in the pathophysiology of the syndrome. Treatment with astemizole increased the temperature threshold to wealing, but not to itch or erythema. The patient was partially desensitized by repeated exposure to heat and this was further improved by indomethacin. After treatment there was no increase in plasma prostaglandin D2 on challenge. No evidence was found for the activation of the alternative complement pathway.

Cold urticaria with vasculitis: report of a case with light and electron microscopic, immunofluorescence and pharmacological studies

An unusual form of essential acquired cold urticaria occurring in a 30‐year‐old woman is reported. Exposure of the skin to cold produced immediate wealing and angio‐oedema with subsequent deep bruising, and severe systemic symptoms.

A timed study of the histopathology, direct immunofluorescence and ultrastructural findings in idiopathic cold-contact urticaria over a 24-h period

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.

Psoriatic skin lesions contain a novel lipid neutrophil chemokinetic compound which is distinct from known chemoattractant eicosanoids

1 Lipid extracts of scale from the lesions of the skin disease psoriasis were purified by high performance liquid chromatography (h.p.l.c.). Assay of fractions by an agarose microdroplet method showed the presence of a novel neutrophil chemokinetic compound which possessed the chromatographic properties of a monohydroxy fatty acid, yet was distinct from the chemoattractant eicosanoid, 12‐hydroxyeicosatetraenoic acid, previously isolated in psoriasis. 2 The novel material, termed compound X, was also detected in fractions collected on h.p.l.c. of extracts of chamber fluid samples obtained from abraded psoriatic lesions, but was not detectable in samples from clinically normal skin. 3 Comparison of the straight and reversed phase h.p.l.c. retention times of compound X with those of a range of standard monohydroxy fatty acids, together with further analysis by gas chromatography — mass spectrometry and assay of selected standards for neutrophil chemokinetic activity, failed to reveal the structural identity of compound X. 4 The finding of a further compound in psoriatic lesions, which stimulates neutrophil movement, highlights the complexity of inflammatory mediator production in this disease.

Alcohol-induced urticaria.

A patient with urticaria induced specifically by alcohol is described. After challenge, a rise in blood histamine was demonstrated. The reaction was not blocked by sodium cromoglycate, indomethacin, chlorpheniramine, cimetidine or naloxone. It is suggested that the reaction was partly mediated by histamine, but that other mediators were probably involved and that these could be involved in some of the more common types of urticaria.

Cold urticaria in association with cholinergic urticaria

The coexistence of two or more varieties of physical urticaria is well recognized but is frequently diagnostically confusing. We now report 13 patients with concurrent cold and cholinergic urticaria in whom heterogeneity in clinical presentation was a striking feature. Four patients showed a hitherto unreported local reaction to cold which bore the clinical appearance of the rash of cholinergic urticaria, but which could not be inhibited by blockade of cholinergic receptors. In two patients the ice‐cube test was negative, but exposure of the whole body to cold induced a generalized rash resembling classical heat‐or exercise‐induced cholinergic urticaria as described by Kaplan.1 Cold and cholinergic urticaria coexisted in their classical form in the remainder. Systemic symptoms occurred following severe cold exposure in three patients and following exercise in six patients. Of the nine patients we were able to review, three had spontaneously cleared of both types of urticaria after intervals of 5,6 and 26 years, respectively, following onset.