Ann Dermatol Vener
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Urticaria is a dermal edema resulting from vascular dilatation and leakage of fluid into the skin in response to molecules released from mast cells. The major mediator responsible for urticaria is histamine. However, the clinical spectrum and pattern of lesions indicate that other molecules, including prostaglandins, leukotrienes, cytokines, and chemokines, produced at different times after mast cell activation contribute to the polymorphism of this symptom and the variable evolution of this disease. ⋯ Finally, under certain circumstances, T-cells can induce activation of mast cells, as well as histamine release (type IV HS). Nonimmunological urticarias result from mast cell activation through membrane receptors involved in innate immunity (e.g., complement, Toll-like, cytokine/chemokine, opioid) or by direct toxicity of xenobiotics (haptens, drugs). In conclusion, urticaria may result from different pathophysiological mechanisms that explain the great heterogeneity of clinical symptoms and the variable responses to treatment.
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Herein we report a case of phlegmasia cerulea dolens, a form of venous thrombosis complicated by arterial ischaemia. ⋯ Phlegmasia cerulea dolens is a particular type of deep venous thrombosis in which a proximal venous thrombus is combined with arterial ischaemic signs due to brutal and massive oedema and slowing down of arterial flow. In most cases, the lower limbs are involved, with malignancy being the most common cause. It should be suspected in the presence of the classical triad of "pain, oedema and cyanosis", with confirmation by Doppler ultrasound. There is no general consensus regarding standard management. Traditionally, systemic anticoagulation has been the mainstay of treatment for this condition. Endovascular surgery may be a possibility in some cases. Prompt diagnosis and rapid treatment initiation are paramount in order to improve the prognosis of this severe condition with ominous prospects.