Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Anaphylaxis

Anaphylaxis is defined as a serious allergic reaction that is rapid in onset and may cause death. Anaphylaxis in children, particularly infants, is underdiagnosed. Anaphylaxis occurs when there is a sudden release of potent, biologically active mediators from mast cells and basophils, leading to cutaneous (urticaria, angioedema, flushing), respiratory (bronchospasm, laryngeal edema), cardiovascular (hypotension, dysrhythmias, myocardial ischemia), and gastrointestinal (nausea, colicky abdominal pain, vomiting, diarrhea) symptoms…

Urticaria (Hives) and Angioedema

Urticaria and angioedema affect 20% of individuals at some point in their life. Episodes of hives that last for <6 wk are considered acute, whereas those that occur on most days of the week for >6 wk are designated chronic. The distinction is important, because the causes and mechanisms of urticaria formation and the therapeutic approaches are different in each instance. Etiology and Pathogenesis Acute urticaria and angioedema…

Ocular Allergies

The eye is a common target of allergic disorders because of its marked vascularity and direct contact with allergens in the environment. The conjunctiva is the most immunologically active tissue of the external eye. Ocular allergies can occur as isolated target organ disease or more often in conjunction with nasal allergies. Ocular symptoms can significantly affect quality of life. Clinical Manifestations There are a few distinct…

Insect Allergy

Allergic responses to stinging or, more rarely, biting insects vary from localized cutaneous reactions to systemic anaphylaxis. Allergic reactions caused by inhalation of airborne particles of insect origin result in acute and chronic respiratory symptoms of seasonal or perennial rhinitis, conjunctivitis, and asthma. Etiology Most reactions to stinging and biting insects, such as those induced by wasps, mosquitoes, flies, and fleas, are limited to a primary…

Atopic Dermatitis (Atopic Eczema)

Atopic dermatitis (AD) , or eczema, is the most common chronic relapsing skin disease seen in infancy and childhood. It affects 10–30% of children worldwide and frequently occurs in families with other atopic diseases. Infants with AD are predisposed to development of food allergy, allergic rhinitis, and asthma later in childhood, a process called the atopic march . Etiology AD is a complex genetic disorder that…

Childhood Asthma

Asthma is a chronic inflammatory condition of the lung airways resulting in episodic airflow obstruction. This chronic inflammation heightens the twitchiness of the airways— airways hyperresponsiveness (AHR)— to common provocative exposures. Asthma management is aimed at reducing airways inflammation by minimizing proinflammatory environmental exposures, using daily controller antiinflammatory medications, and controlling comorbid conditions that can worsen asthma. Less inflammation typically leads to better asthma control, with…

Allergic Rhinitis

Allergic rhinitis (AR) is a common chronic disease affecting 20–30% of children. AR is an inflammatory disorder of the nasal mucosa marked by nasal congestion, rhinorrhea, and itching, often accompanied by sneezing and conjunctival inflammation. Its recognition as a major chronic respiratory disease of children derives from its high prevalence, detrimental effects on quality of life and school performance, and comorbidities. Children with AR often have…

Diagnosis of Allergic Disease

Allergy History Obtaining a complete history from the allergic patient involves eliciting a description of all symptoms along with their timing and duration, exposure to common allergens, and responses to previous therapies. Because patients often suffer from more than one allergic disease, the presence or absence of other allergic diseases, including allergic rhinoconjunctivitis, asthma, food allergy, eosinophilic esophagitis, atopic dermatitis, and drug allergy, should be determined.…

Allergy and the Immunologic Basis of Atopic Disease

Allergic or atopic patients have an altered state of reactivity to common environmental and food antigens that do not cause clinical reactions in unaffected people. Patients with clinical allergy usually produce immunoglobulin E (IgE) antibodies to the antigens that trigger their illness. The term allergy represents the clinical expression of IgE-mediated allergic diseases that have a familial predisposition and that manifest as hyperresponsiveness in target organs…

Late Effects of Hematopoietic Stem Cell Transplantation

Pediatric hematopoietic stem cell transplantation (HSCT) is considered standard-of-care treatment for a number of malignant and nonmalignant conditions. Treatment generally involves exposure to chemotherapy and occasionally radiation to encourage engraftment of donor stem cells and prevent donor and recipient rejection. The period of time immediately after transplant is associated with the risk for a number of serious acute complications, including profound immunosuppression and subsequent risk for…

Graft-Versus-Host Disease, Rejection, and Venoocclusive Disease

A major cause of mortality and morbidity after allogeneic hematopoietic stem cell transplantation (HSCT) is graft-versus-host disease (GVHD) , which is caused by engraftment of immunocompetent donor T lymphocytes in an immunologically compromised host who shows histocompatibility differences with the donor. These differences between the donor and the host may result in donor T-cell activation against either recipient major histocompatibility complex (MHC) antigens or minor histocompatibility…

Hematopoietic Stem Cell Transplantation From Alternative Sources and Donors

Two thirds of patients who need allogeneic hematopoietic stem cell transplantation (HSCT) do not have an available HLA-identical sibling. Alternative sources of hematopoietic stem cells (HSCs) are being increasingly used and include matched unrelated donors, unrelated umbilical cord blood , and HLA-haploidentical relatives . Each of these 3 options has advantages and limitations, but rather than being considered competing alternatives, they should be regarded as complementary…

Principles and Clinical Indications of Hematopoietic Stem Cell Transplantation

Allogeneic (from a donor) or autologous (from the same individual) hematopoietic stem cells have been used to cure both malignant and nonmalignant disorders. Autologous transplantation is employed as a rescue strategy after delivering otherwise lethal doses of chemotherapy with or without radiotherapy in children with hematologic malignancies such as relapsed lymphoma or selected solid tumors (e.g., neuroblastoma, brain tumors). Allogeneic transplantation is used to treat children…

Disorders of the Complement System

Evaluation of the Complement System Richard B. Johnston Keywords hereditary angioedema total hemolytic complement activity CH 50 alternative pathway activity AP 50 Testing for total hemolytic complement activity (CH 50 ) effectively screens for most of the common diseases of the complement system. A normal result in this assay depends on the ability of all 11 components of the classical pathway and membrane attack complex to interact…

Complement Components and Pathways

Complement is an exquisitely balanced, highly influential system that is fundamental to the clinical expression of host defense and inflammation. The complement system also has the capacity to perform functions beyond host defense, such as promoting phagocytic removal of dying cells, molecular debris, and weak or superfluous synapses during brain formation. Complement components and receptors function within individual cells and can stabilize intracellular homeostasis. However, complement…

Leukocytosis

Leukocytosis is an elevation in the total leukocyte or white blood cell (WBC) count that is 2 SD above the mean for age (see Chapter 748 ). It is most often caused by elevated numbers of neutrophils (i.e., neutrophilia), although marked increases in monocytes, eosinophils, basophils, and lymphocytes can be seen. Before extensive evaluation, it is important to assess for spurious elevations in the WBC count…

Leukopenia

Leukopenia refers to an abnormally low number of white blood cells (WBCs) in the circulating blood secondary to a paucity of lymphocytes, granulocytes, or both. Because there are marked developmental changes in normal values for WBC counts during childhood (see Chapter 748 ), normal ranges must be considered in the context of age. For newborns, the mean WBC count at birth is high, followed by a…

Disorders of Phagocyte Function

Neutrophils are the first line of defense against microbial invasion. They arrive at the site of inflammation during the critical 2-4 hr after microbial invasion to contain the infection and prevent hematogenous dissemination. This well-orchestrated process is one of the most interesting stories in modern cell biology. In fact, much of our knowledge about neutrophil function derives from studies done in patients with genetic errors in neutrophil…

Eosinophils

Eosinophils are distinguished from other leukocytes by their morphology, constituent products, and association with specific diseases. Eosinophils are nondividing, fully differentiated cells with a diameter of approximately 8 µm and a bilobed nucleus. They differentiate from stem cell precursors in the bone marrow under the control of T-cell–derived interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and especially IL-5. Their characteristic membrane-bound specific granules stain bright pink with eosin…