Items in AFP with MESH term: Histamine H1 Antagonists
ABSTRACT: In a select group of persons, exercise can produce a spectrum of allergic symptoms ranging from an erythematous, irritating skin eruption to a life-threatening anaphylactic reaction. The differential diagnosis in persons with exercise-induced dermatologic and systemic symptoms should include exercise-induced anaphylaxis and cholinergic urticaria. Both are classified as physical allergies. Mast cell degranulation with the release of vasoactive substances appears to be an inciting factor for the production of symptoms in both cases. Exercise-induced anaphylaxis and cholinergic urticaria can be differentiated on the basis of urticarial morphology, reproducibility, progression to anaphylaxis and response to passive warming. Diagnosis is usually based on a thorough history and examination of the morphology of the lesions. Management of acute episodes of exercise-induced anaphylaxis includes cessation of exercise, administration of epinephrine and antihistamines, vascular support and airway maintenance. Long-term care may require modification of or abstinence from exercise, avoidance of co-precipitating factors and the prophylactic use of medications such as antihistamines and mast cell stabilizers.
A Practical Guide to Anaphylaxis - Article
ABSTRACT: Anaphylaxis is a life-threatening reaction with respiratory, cardiovascular, cutaneous, or gastrointestinal manifestations resulting from exposure to an offending agent, usually a food, insect sting, medication, or physical factor. It causes approximately 1,500 deaths in the United States annually. Occasionally, anaphylaxis can be confused with septic or other forms of shock, asthma, airway foreign body, panic attack, or other entities. Urinary and serum histamine levels and plasma tryptase levels drawn after onset of symptoms may assist in diagnosis. Prompt treatment of anaphylaxis is critical, with subcutaneous or intramuscular epinephrine and intravenous fluids remaining the mainstay of management. Adjunctive measures include airway protection, antihistamines, steroids, and beta agonists. Patients taking beta blockers may require additional measures. Patients should be observed for delayed or protracted anaphylaxis and instructed on how to initiate urgent treatment for future episodes.
ABSTRACT: Urticaria (i.e., pruritic, raised wheals) and angioedema (i.e., deep mucocutaneous swelling) occur in up to 25 percent of the U.S. population. Vasoactive mediators released from mast cells and basophils produce the classic wheal and flare reaction. Diagnosis can be challenging, especially if symptoms are chronic or minimally responsive to therapy. A thorough medical history, physical examination, and methodical investigation are necessary to uncover diagnostic clues. Although serious medical illness can occur concurrently with chronic urticaria, acute urticaria generally is benign and self-limited. The mainstay of therapy for urticaria is avoidance of known triggering agents, judicious use of oral corticosteroids, and treatment with long-acting second-generation antihistamines, H2-receptor antagonists, tricyclic antidepressants, and anti-inflammatory leukotriene antagonists. Consultation for investigative therapy may be necessary if symptoms continue despite a stepwise approach to diagnosis and therapy.
Practical Selection of Antiemetics - Article
ABSTRACT: An understanding of the pathophysiology of nausea and the mechanisms of antiemetics can help family physicians improve the cost-effectiveness and efficacy of therapy. Nausea and vomiting are mediated primarily by visceral stimulation through dopamine and serotonin, by vestibular and central nervous system causes through histamine and acetylcholine, and by chemoreceptor trigger zone stimulation through dopamine and serotonin. Treatment is directed at these pathways. Antihistamines and anticholinergic agents are most effective in patients with nausea resulting from vestibular and central nervous system causes. Dopamine antagonists block dopamine in the intestines and chemoreceptor trigger zone; indications for these agents are similar to those for serotonin antagonists. Serotonin antagonists block serotonin in the intestines and chemoreceptor trigger zone, and are most effective for treating gastrointestinal irritation and postoperative nausea and vomiting. Complementary and alternative therapies, such as ginger, acupressure, and vitamin B6, have variable effectiveness in the treatment of pregnancy-induced nausea.
Pityriasis Rosea - Article
ABSTRACT: Pityriasis rosea is a common, acute exanthem of uncertain etiology. Viral and bacterial causes have been sought, but convincing answers have not yet been found. Pityriasis rosea typically affects children and young adults. It is characterized by an initial herald patch, followed by the development of a diffuse papulosquamous rash. The herald patch often is misdiagnosed as eczema. Pityriasis rosea is difficult to identify until the appearance of characteristic smaller secondary lesions that follow Langer's lines (cleavage lines). Several medications can cause a rash similar to pityriasis rosea, and several diseases, including secondary syphilis, are included in the differential diagnosis. One small controlled trial reported faster clearing of the exanthem with the use of erythromycin, but the mechanism of effect is unknown. Resolution of the rash may be hastened by ultraviolet light therapy but not without the risk of hyperpigmentation. Topical or systemic steroids and antihistamines often are used to relieve itching.
Vasomotor Rhinitis - Article
ABSTRACT: Vasomotor rhinitis affects millions of Americans and results in significant symptomatology. Characterized by a combination of symptoms that includes nasal obstruction and rhinorrhea, vasomotor rhinitis is a diagnosis of exclusion reached after taking a careful history, performing a physical examination, and, in select cases, testing the patient with known allergens. According to a 2002 evidence report published by the Agency for Healthcare Research and Quality (AHRQ), there is insufficient evidence to reliably differentiate between allergic and nonallergic rhinitis based on signs and symptoms alone. The minimum level of diagnostic testing needed to differentiate between the two types of rhinitis also has not been established. An algorithm is presented that is based on a targeted history and physical examination and a stepwise approach to management that reflects the AHRQ evidence report and U.S. Food and Drug Administration approvals. Specific approaches to the management of rhinitis in children, athletes, pregnant women, and older adults are discussed.
Treatment of the Common Cold - Article
ABSTRACT: The common cold is a viral illness that affects persons of all ages, prompting frequent use of over-the-counter and prescription medications and alternative remedies. Treatment focuses on relieving symptoms (e.g., cough, nasal congestion, rhinorrhea). Dextromethorphan may be beneficial in adults with cough, but its effectiveness has not been demonstrated in children and adolescents. Codeine has not been shown to effectively treat cough caused by the common cold. Although hydrocodone is widely used and has been shown to effectively treat cough caused by other conditions, the drug has not been studied in patients with colds. Topical (intranasal) and oral nasal decongestants have been shown to relieve nasal symptoms and can be used in adolescents and adults for up to three days. Antihistamines and combination antihistamine/decongestant therapies can modestly improve symptoms in adults; however, the benefits must be weighed against potential side effects. Newer nonsedating antihistamines are ineffective against cough. Topical ipratropium, a prescription anticholinergic, relieves nasal symptoms in older children and adults. Antibiotics have not been shown to improve symptoms or shorten illness duration. Complementary and alternative therapies (i.e., Echinacea, vitamin C, and zinc) are not recommended for treating common cold symptoms; however, humidified air and fluid intake may be useful without adverse side effects. Vitamin C prophylaxis may modestly reduce the duration and severity of the common cold in the general population and may reduce the incidence of the illness in persons exposed to physical and environmental stresses.
Treatment Options for Atopic Dermatitis - Article
ABSTRACT: Atopic dermatitis is a common inflammatory skin condition that usually affects children. It is a chronic disease, with periods of remission and flare-ups, that adversely affects the quality of life of patients and their families. Aggressive therapy with emollients is an important intervention for patients with atopic dermatitis. Patients should avoid individual disease triggers and allergens. Topical corticosteroids are the mainstay of treatment for flare-ups and are the standard to which other treatments are compared. Topical calcineurin inhibitors should not be used in patients younger than two years or in those who are immunosuppressed, and should be secondline therapies in other patients. Rarely, systemic agents (e.g., cyclosporine, interferon gamma-1b, oral corticosteroids) may be considered in adults.
ABSTRACT: Atopic dermatitis is a common, potentially debilitating condition that can compromise quality of life. Its most frequent symptom is pruritus. Attempts to relieve the itch by scratching simply worsen the rash, creating a vicious circle. Treatment should be directed at limiting itching, repairing the skin and decreasing inflammation when necessary. Lubricants, antihistamines and topical corticosteroids are the mainstays of therapy. When required, oral corticosteroids can be used. If pruritus does not respond to treatment, other diagnoses, such as bacterial overgrowth or viral infections, should be considered. Treatment options are available for refractory atopic dermatitis, but these measures should be reserved for use in unique situations and typically require consultation with a dermatologist or an allergist.
ABSTRACT: Interstitial cystitis is a chronic, severely debilitating disease of the urinary bladder. Excessive urgency and frequency of urination, suprapubic pain, dyspareunia, chronic pelvic pain and negative urine cultures are characteristic of interstitial cystitis. The course of the disease is usually marked by flare-ups and remissions. Other conditions that should be ruled out include bacterial cystitis, urethritis, neoplasia, vaginitis and vulvar vestibulitis. Interstitial cystitis is diagnosed by cystoscopy and hydrodistention of the bladder. Glomerulations or Hunner's ulcers found at cystoscopy are diagnostic. Oral treatments of interstitial cystitis include pentosan polysulfate, tricyclic antidepressants and antihistamines. Intravesicular therapies include hydrodistention, dimethyl sulfoxide and heparin, or a combination of agents. Referral to a support group should be offered to all patients with interstitial cystitis.