Allergic disorders

IgE-mediated allergic reactions (p. 72) involve mast cell release of histamine (p. 114) and production of other mediators (such as leukotrienes, p. 196). Resultant responses include relaxation of vascular smooth muscle, as evidenced locally by vasodilation (e.g., conjunctival congestion) or systemically by hypotension (as in anaphylactic shock) enhanced capillary permeability with transudation of fluid into tissues— swelling of conjunctiva and mucous membranes of the upper airways ( hay fever ), cutaneous wheal formation contraction of bronchial smooth muscle-bronchial asthma stimulation of intestinal smooth musde—diarrhea. 

Stabilization of mast cells. Cromolyn prevents IgE-mediated release of mediators, although only after chronic treatment. Moreover, by interfering with the actions of mediator substances on inflammatory cells, it causes a more general inhibition of allergic inflammation. It is applied locally to conjunctiva, nasal mucosa, bronchial tree (inhalation), intestinal mucosa (absorption almost nil with oral intake). Indications prophylaxis of hay fever, allergic asthma, and food allergies. 

Blockade of histamine receptors. Allergic reactions are predominantly mediated by H receptors. Hi antihistamines (p. 114) are mostly used orally. Their therapeutic effect is often disappointing. Indications allergic rhinitis (hay fever). 

Functional antagonists of mediators of allergy, a) a-Sympathomi-metics, such as naphazoline, oxymeta-zoline, and tetrahydrozoline, are applied topically to the conjunctival and nasal mucosa to produce local vasoconstriction, and decongestion and to dry up secretions (p. 90), e.g., in hay fever. Since they may cause mucosal damage, their use should be short-term. 

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Hypotension and allergic disorders, asthma 25/mg—50 mg IM, SO, or IV topical nasal decongestant instill in each nostril q4h... 

B cells also have impact on T-cell differentiation. B-cell antigen presentation plays an important role at promoting Th2 responses and pathophysiology during allergic disorders. It has been shown that B-cell -/- mice and in mice selectively deficient in MHCII on B cells had decreased Th2 cytokines IL-4 and IL-5 [152]. Also in another study it has been reported that B-cell-derived exosomes can present allergen peptides and activate allergen-specific T cells to proliferate and produce Th2 cytokines IL-5 and IL-13 [42]. 

Anaphylaxis is the most dramatic and potentially catastrophic manifestation of allergic disorders. It can affect virtually any organ including the cardiovascular system. Cardiovascular collapse and hypotensive shock in anaphylaxis have been attributed to peripheral vasodilation, enhanced vascular permeability and plasma leakage, rather than any direct effect on the myocardium. However, there is increasing experimental and clinical evidence that the human heart is a site and target of anaphylaxis. 

Simons FE Hi-antihistamines more relevant than ever in the treatment of allergic disorders. J Allergy Clin Immunol 2003 112 42-52. 63... 

Sigesbeckia glabrescens Mak., or hi chum (Korean Fig. 21), is used in Korea to treat liver and kidney diseases, asthma, allergic disorders, costiveness, deafness, and blindness. In China, the plant is prescribed for rheumatic pain, numbness, weak bones, and to wash boils. The anti-inflammatory property of Sigesbeckia glabrescens Mak. is... 

The work summarized herein extends our view on the role of mast cells not only in allergic disorders but in immunity in general. As known so far, this is... 

Goldman M Translational mini-review series on toll-like receptors toll-like receptor ligands as novel pharmaceuticals for allergic disorders. Clin Exp Immunol 2007 147 208-216. 

Importantly, although Th2 cells are responsible for the development of allergic diseases, Thl cells may contribute to chronicity and effector phase in allergic diseases [30-33,38,39]. Distinct Thl and Th2 2 subpopulations of T cells counterregulate each other and play a role in distinct diseases [34,35]. In addition, recent studies have demonstrated that peripheral T-cell tolerance is crucial for a healthy immune response and successful treatment of allergic disorders [40-42]. A further subtype ofT cells, with immunosuppressive function and cytokine profiles distinct from either Thl and Th2 cells, termed regulatory/suppressor T cells (Treg), has been existence in humans has been demonstrated [41,... 

Asthma - Ephedrine sulfate injection is indicated in the treatment of allergic disorders, such as bronchial asthma. Oral ephedrine is indicated for temporary relief of shortness of breath, tightness of chest, and wheezing caused by bronchial asthma. Eases breathing for asthma patients by reducing spasms of bronchial muscles. 

Newer developments are astemizole, cetirizine, loratadine, mequitazine and terfenadine which are basically devoid of central side effects and effects on the autonomic transmission. This is not due to an inability of the drugs to pass the blood brain barrier, since these drugs are quite lipophilic but probably to their selectivity towards Hi-receptors. These drugs can be used in the chronic treatment of allergic disorders. 

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