Diffuse Cutaneous Bullous Mastocytosis and Disseminated Intravascular Coagulation Postvaccination: A Case Report.

BACKGROUND: Diffuse cutaneous bullous mastocytosis is the most rare subtype of cutaneous mastocytosis, characterized by generalized skin infiltration with mast cells and blistering. OBJECTIVE: To increase the awareness of the natural history and potential adverse complications of this rare cutaneous condition. METHOD AND RESULTS: We report a case of a male diagnosed on day 7 of life with follow-up of his progression over 6 years. When he was 2.5 months old, he was admitted to hospital postvaccinations with a flare of his blistering that was complicated by disseminated intravascular coagulation and polyuric acute tubular necrosis. Blistering ceased at 3 years, but at 6 years, extensive urtication continued in response to known triggers and a suboptimal dose of mast cell membrane stabilizers and histamine-1 and -2 receptor antagonists. CONCLUSION: This case discusses the progression of this rare condition over 6 years and highlights the importance of reaching optimal pharmacologic blockage of histamine-1 and -2 receptors and stabilization of mast cell membranes in patients persistently experiencing ongoing pruritus, urtication, and flushing symptoms.

Pimecrolimus induces apoptosis of mast cells in a murine model of cutaneous mastocytosis.

BACKGROUND: Cutaneous mastocytosis (CM) is a common type of mastocytosis. Current treatment of CM is generally symptomatic. Pimecrolimus has been demonstrated as an effective anti-inflammatory drug for the treatment of inflammatory skin diseases, but whether it treats CM remains unknown. METHODS: The murine model of CM was induced by subcutaneous injection of 100 µg/kg recombinant murine stem cell factor (rmSCF) for a total of 17 days in Balb/c mice. Beginning on the 8th day, treatment with pimecrolimus 1% cream or vehicle was performed topically and daily for 10 days. The clinical signs of CM were scored, and pathological analysis was performed with toluidine blue staining and hematoxylin and eosin staining. The in situ apoptotic mast cells (MCs) were studied by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. The cutaneous histamine level was measured by ELISA. RESULTS: In the rmSCF-treated mice, the clinical signs of CM, including erythema, wheal after rubbing lesion skins, and increased thickness of skin, were obvious compared to control mice, and were reduced after pimecrolimus treatment. The numbers of cutaneous MCs and neutrophils were significantly greater in mice with CM than in control mice, and pimecrolimus treatment decreased the numbers of MCs but not neutrophils. Extensive apoptosis of cutaneous MCs was observed in pimecrolimus-treated mice. The cutaneous histamine level was elevated in the mice with CM compared with healthy controls, and was lowered after treatment with pimecrolimus. CONCLUSIONS: Pimecrolimus effectively treats CM by reducing the density of cutaneous MCs and the subsequent histamine production through inducing MCs apoptosis.

Association of transient dermal mastocytosis and elevated plasma tryptase levels with development of adverse reactions after treatment of onchocerciasis with ivermectin.

To investigate the role of mast cells in treatment-associated adverse reactions in patients with onchocerciasis, changes in plasma tryptase levels and skin mast cell counts were examined in 2 groups of Onchocerca volvulus-infected subjects after ivermectin treatment. After treatment, an increase in tryptase levels was observed concurrent with the onset of blood eosinopenia and preceding the appearance of plasma eosinophil-derived neurotoxin (EDN) and interleukin-5. Tryptase levels were correlated with development of peripheral eosinopenia and markers of eosinophil activation and degranulation. Dermal mast cell numbers increased transiently at 24 h after treatment, preceding the onset of dermal eosinophil infiltration and the development of clinically apparent inflammation. Local reactions were strongly correlated with levels of plasma tryptase and EDN, and the severity of systemic reactions was correlated with levels of tryptase, EDN, and interleukin-5. The data indicate that mast cells play a role in initiation of tissue inflammatory reactions after ivermectin treatment of onchocerciasis.