Enalaprilat, but not cilazaprilat, increases inflammatory skin reactions in guinea-pigs

Psoriatic erythroderma associated with enalapril

A 59-year-old man with a 35-year personal and positive family history of psoriasis was admitted to our department for treatment of psoriatic erythroderma. The patient had commenced therapy with enalapril 10 mg b.i.d. for the treatment of hypertension approximately 6 weeks before hospitalization. Five weeks after the initiation of enalapril, his psoriasis began to flare, and for a period of about 1 week it reached the extent of erythroderma. The patient did not associate the psoriatic flare with other factors such as infections, trauma, or stress. The patient presented with diffuse erythema and pronounced desquamation covering his entire trunk, scalp, and extremities (Figure). Nearly 100% of the body surface area was involved. The palms and soles were also affected, displaying erythema, hyperkeratosis, and painful fissures. The nails showed pits, oil spots, and subungual hyperkeratosis. The patient also had psoriatic arthritis affecting the interphalangeal joints of his fingers. Laboratory tests revealed an elevated erythrocyte sedimentation rate, an elevated creatinine level of 180 mmol/L, a blood urea nitrogen level of 10.8 mmol/L, and a uric acid level of 716 mmol/L. Urinalysis showed proteinuria of 1.5 g/24 h. The patient's renal condition was diagnosed as chronic tubulointerstitial nephritis, most probably related to his dermatologic disease. Allopurinol and dietary measures were recommended. Following treatment with methotrexate and replacement of enalapril therapy, the erythema and scaling gradually subsided and became confined to his pre-eruptive chronic plaques (approximately 5% of body surface area). Rechallenge with enalapril was not performed.

Neuropeptides in the skin: interactions between the neuroendocrine and the skin immune systems

The interaction between components of the nervous system and multiple target cells in the cutaneous immune system has been receiving increasing attention. It has been observed that certain skin diseases such as psoriasis and atopic dermatitis have a neurogenic component. Neuropeptides released by sensory nerves that innervate the skin and often contact epidermal and dermal cells can directly modulate functions of keratinocytes, Langerhans cells (LC), mast cells, dermal microvascular endothelial cells and infiltrating immune cells. Among these neuropeptides the tachykinins substance P (SP) and neurokinin A (NKA), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and somatostatin (SOM) have been reported to effectively modulate skin and immune cell functions such as cell proliferation, cytokine production or antigen presentation under physiological or pathophysiological conditions. Expression and regulation of their corresponding receptors that are expressed on a variety of skin cells as well as the presence of neuropeptide-specific peptidases such as neutral endopeptidase (NEP) or angiotensin-converting enzyme (ACE) determine the final biological response mediated by these peptides on the target cell or tissue. Likewise, skin cells like keratinocytes or fibroblasts are a source for neurotrophins such as nerve growth factor that are required not only for survival and regeneration of sensory neurons but also to control responsiveness of these neurons to external stimuli. Therefore, neuropeptides, neuropeptide receptors, neuropeptide-degrading enzymes and neurotrophins participate in a complex, interdependent network of mediators that modulate skin inflammation, wound healing and the skin immune system. This review will focus on recent studies demonstrating the role of tachykinins, CGRP, SOM and VIP and their receptors and neuropeptide-degrading enzymes in mediating neurogenic inflammation in the skin.

ACE inhibitor-induced angioedema. Incidence, prevention and management

Available information from 1980 to 1997 on angiotensin converting enzyme (ACE) inhibitor-induced angioedema and its underlying mechanisms are summarised and discussed. The incidence of angioedema is low (0.1 to 0.2%) but can be considered as a potentially life-threatening adverse effect of ACE inhibitor therapy. This adverse effect of ACE inhibitors, irrespective of the chemical structure, can occur early in treatment as well as after prolonged exposure for up to several years. The estimate incidence is quite underestimated. The actual incidence can be far higher because of poorly recognised presentation of angioedema as a consequence of its late onset in combination with usually long term therapy. Also, a spontaneous reporting bias can contribute to an actual higher incidence of this phenomenon. The incidence can be even higher (up to 3-fold) in certain risk groups, for instance Black Americans. Treatment includes immediate withdrawal of the ACE inhibitor and acute symptomatic supportive therapy followed by immediate (and long term) alternative therapy with other classes of drugs to manage hypertension and/or heart failure. Preclinical and clinical studies for the elucidation of the underlying mechanism(s) of ACE inhibitor-associated angioedema have not generated definite conclusions. It is suggested that immunological processes and several mediator systems (bradykinin, histamine, substance P and prostaglandins) are involved in the pathogenesis of angioedema. A great part of all reviewed reports suggest a relationship between ACE inhibitor-induced angioedema and increased levels of (tissue) bradykinin. However, no conclusive evidence of the role of bradykinin in angioedema has been found and an exclusive role of bradykinin seems unlikely. So far, no clear-cut evidence for an immune-mediated pathogenesis has been found. In addition, ACE gene polymorphism and some enzyme deficiencies are proposed to be involved in ACE inhibitor-induced angioedema. Progress in pharmacogenetic and molecular biological research should throw more light on a possible genetic component in the pathogenesis of ACE inhibitor-associated angioedema.