Only $2.99/month

Terms in this set (70)

Typically, unless a specific trigger is suspected, chronic urticaria does not warrant allergy testing.
Chronic urticaria is defined by the presence of hives on most days of the week for a period of 6 weeks or longer.

Initial screening tests for disorders most commonly associated with urticaria include: a complete blood count with differential, markers of inflammation (C-reactive protein or erythrocyte sedimentation rate), liver function tests, urine analysis, and a thyroid-stimulating hormone level. Skin or serum-specific IgE allergy testing is typically not indicated unless a specific trigger is suspected on the basis of history.

The history should be geared toward (1) differentiating between vasculitic (duration of lesions >72 hours, pain, discoloration, or residual scarring) and nonvasculitic urticaria (duration <72 hours and absence of above signs), (2) identifying possible underlying cause, and (3) ensuring that the patient does not have evidence of a more serious systemic disease (fever, weight loss, arthralgias, and other constitutional symptoms). It is helpful to approach patients on the basis of broad categories of mechanisms such as IgE-dependent mechanisms (eg, drug, food, insect venom, and latex exposure) and complement-mediated mechanisms (eg, hereditary angioedema and serum sickness).

Other factors to consider include (1) physical urticarias; (2) underlying infection; (3) autoimmune etiology; (4) possible hormonal effects, especially when hives in women occur on a cyclic basis; (5) association with malignant tumor; (6) pertinent occupational exposure; (7) multiple/repetitive or late onset reactions to insect stings/bites; (8) direct contact of skin or oropharynx with foods, chemicals, animal saliva, and other substances; (9) familial pattern/ hereditary syndromes; and (10) psychologic stresses.
You are called to the emergency department to evaluate a 5-day-old male newborn who was brought in by ambulance because of a prolonged episode of twitching and perioral cyanosis at home. Over the course of several hours before this episode, he was noted to be fussy, did not feed well, and seemed less active. The parents report he acted well the day before, and they did not note any fever.

His birth weight was 3 kg, and he had an Apgar score 8 at 1 min and 9 at 5 min. The prenatal course and delivery are said to be unremarkable. The mother was negative for group B Streptococcus, human immunodeficiency virus, and rapid plasma reagin. He was discharged home at 2 days of age.

On physical examination, the baby's temperature is 35.9°C, heart rate is 160 beats/min, blood pressure is 52/32 mm Hg, and respiratory rate is 56 breaths/min.

The newborn is floppy with little spontaneous activity. His anterior fontanelle is full, and his skin is noted to be without lesions. A head, ears, eyes, nose, and throat examination shows positive red reflex bilaterally. His neck is supple. His lungs have shallow respirations. His heart has a regular rhythm without murmur, rub, or gallop. His abdomen is distended and soft, and his liver edge is palpable. Findings on genitourinary examination are unremarkable. His extremities are without lesions.

Laboratory test results include the following:
•White blood cell count, 1,800/µL (1.8 ×109/L), with 37% neutrophils, 22% bands, 7% metamyelocytes, 32% lymphocytes, and 2% basophils
•Hemoglobin, 14.2 g/dL (142 g/L)

•Platelets, 122 × 103/µL (122 × 109/L)

Analysis of his cerebrospinal fluid shows the following:
•White blood cell count, 1,932/µL (1.9 × 109/L), with 78% neutrophils and 22% lymphocytes
•Glucose, 10 mg/dL (0.6 mmol/L)
•Protein, 0.25 g/dL (2.5 g/L)

A Gram stain shows white blood cells and few gram-negative rods.

Results are shown from a computed tomography scan of the head (Item Q43).

Of the following, the MOST likely infectious agent causing this baby's illness is

A. Citrobacter koseri
B. group B Streptococcus
C. herpes simplex virus
D. Listeria monocytogenes
E. Pseudomonas aeruginosa