Histamine‐containing mast cells and their relationship to NGFr‐immunoreactive nerves in prurigo nodularis: a reappraisal

Abstract

The mast cell, which is a histamine-containing cell, has been found to have far more functions in skin inflammation than hitherto understood. To investigate the appearance of mast cells in prurigo nodularis, histamine immunohistochemistry in combination with nerve growth factor receptor (NGFr) double-staining as well as electron microscopic studies were performed. The results revealed that the histamine-containing cell number was increased in the lesional dermis. The mast cell size was also increased and the shape had become more dendritic. They tended to contact the epidermis and even infiltrated into it. In the histamine and NGFr double-staining, both an increased histamine-containing mast cell number and an increased number of NGFr-immunoreactive nerve fiber profiles were revealed in the upper dermis of the prurigo nodularis lesional skin. Mast cells were seen in close vicinity to NGFr-positive nerves and sometimes even seemingly to contact single nerve fibers. At the ultrastructural level, it is obvious that the mast cell bodies become larger, having more abundant cytoplasm and organelles (e.g. mitochondria), but comparatively fewer characteristic granules. Mast cells were often observed to sprout long dendrites, with or without granules. The cells were also frequently seen to contact other cell types, and a mast cell infiltration into the epidermis was also found. The statistical results of mast cell numbers showed a significant increase in prurigo nodularis lesional skin compared to the normal controls. The present results further indicate that mast cells, together with cutaneous nerve fibers, are actively involved in the pathogenesis of the disease.

Losartan-induced coronary artery spasm

“…The short period of time from losartan ingestion to symptom onset, angiographic findings showing migrating coronary spasms at different locations, severe elevation of markers of cardiac damage (plasma troponin I 237 μg/l), a skin disease (prurigo nodularis) with a higher-than-normal level of mast cells2 suggested an allergic myocardial infarction in accordance with Kounis syndrome type 1.…”

Foods, Drugs and Environmental Factors: Novel Kounis Syndrome Offenders

“…Finally, plasmapheresis was initiated, as losartan becomes highly bound to plasma proteins, with a good response. The authors of this report wondered whether their case involved allergic angina and Kounis syndrome, type I variant due to the presence of migrating coronary spasms, severe elevation of the troponin level and skin disease (prurigo nodularis), which are known to be associated with higher than normal levels of mast cells (43).…”

Oral ketotifen and topical antibiotic therapy in the management of pruritus in prurigo nodularis: A randomized, controlled, single-blind, parallel study

“…It has been noted that mast cells in PN lesions are increased in number and show characteristic morphological changes such as an enlarged cell body size and a dendritic shape compared with the round or elongated shape observed in the normal skin. [678] The PN mast cells also have an abundant cytoplasm with a decreased number of granules inside, suggesting that many of the granules have been released into the surrounding tissue. [6] Mast cells in PN have been observed to produce more nerve growth factor (NGF) in the lesional skins.…”

“…[678] The PN mast cells also have an abundant cytoplasm with a decreased number of granules inside, suggesting that many of the granules have been released into the surrounding tissue. [6] Mast cells in PN have been observed to produce more nerve growth factor (NGF) in the lesional skins. This high level of NGF causes neural hyperplasia in the PN lesions.…”

“…[91011] Apart from neural hyperplasia, there are other mast cell products that may contribute to pruritus in PN; these include histamine, tryptase, prostaglandins, and interleucins. [246] In addition to mast cells, higher level of IL-31[12] has been detected in the lesional skin of prurigo nodularis. IL-31 is pruritogenic, can induce itch in atopic individual, and is upregulated by staphyloccal superantigens.…”