A. 1 year
B. 5 years
C. 20 years
D. 45 years
E. 65 years
The correct answer is E. Different leukemias tend to affect populations of different ages. The
disease described is chronic lymphocytic leukemia (CLL), a disease of older adults.
Both the 1-year-old (choice A) and the 5-year-old (choice B) would be most likely to have acute
lymphocytic leukemia (ALL).
The 20-year-old (choice C) would be most likely to have acute myelocytic leukemia (AML).
The 45-year-old (choice D) would be likely to have either AML or chronic myelogenous leukemia
(CML).
102. Which of the following serum chemistry studies will MOST likely be abnormal in a
preteen with polydipsia that develops weight loss despite eating large amounts of food over a
three month period?
A. Blood urea nitrogen
B. Serum bicarbonate
C. Serum calcium
D. Serum glucose
E. Serum sodium
The correct answer is D. Although it is commonly known that diabetes mellitus is associated with
polyuria and polydipsia, many do not realize it is also associated with weight loss despite increased
eating, also known as polyphagia. In our extremely weight- and food-conscious society, this
phenomenon may be much more striking to the patient and his family than a change in the amount of
fluid intake. The lesson learned is that a child who develops weight loss despite increased food intake
should have a blood glucose test.
All of the other answer choices would be expected to be normal in this patient.
103. Which of the following is involved in hypoxia in a smoker with noticeable increase in
anteroposterior chest width if oxygen therapy is effective?
A. Anemia caused by blood loss
B. Edematous tissues
C. Emphysema
D. Localized circulatory deficiencies
E. Right-to-left cardiac shunts
The correct answer is C. Chronic pulmonary emphysema is characterized by distention of small air
spaces distal to the respiratory bronchioles and destruction of alveolar septa. Long-term cigarette
smoking is the usual cause. The marked loss of lung parenchyma associated with emphysema leads
to a decrease in the diffusion capacity of the lungs that reduces their ability to oxygenate blood and
remove carbon dioxide, contributing to the "barrel chest" appearance of these patients. Cigarettes
also inhibit Alpha-1 antitrypsin allowing trypsin to break down proteins in the alveoli. When arterial
hypoxemia is persistent and severe, oxygen therapy should therefore be considered.
Oxygen therapy is less effective for treating the hypoxia associated with anemia (choice A),
edematous tissues (choice B), localized circulatory deficiencies (choice D), and right-to-left cardiac
shunts (choice E), because in each case, there is already adequate oxygen available in the alveoli.
The problem in each of these situations is inadequate transport of oxygen to the tissues, blunting the
effects of increasing the oxygen tension of the inspired air. Oxygen therapy nonetheless increases the
amount of dissolved oxygen carried in the blood, which may be life-saving in some instances.
104. Which of the following characterizes an eczematous reaction that occurs 72 hours after
wearing latex gloves?
A. Irritant dermatitis
B. Type I reaction
C. Type II reaction
D. Type III reaction
E. Type IV reaction
The correct answer is E. Sensitization to latex has become a major healthcare problem. Local skin
irritations are common but more severe allergic reactions occur, up to and including rare anaphylactic
reactions that are occasionally fatal. The immune responses to latex are immediate-type
hypersensitivity (type I) reactions, expressing themselves in minutes, or delayed-type hypersensitivity
(type IV) reactions that express themselves in 48-72 hours. The type I reactions are caused by the
IgE-mediated sensitivity to latex proteins, whereas the type IV reactions are caused by a cell-
mediated response to the chemicals that are added in the processing of latex. The type IV response
in this circumstance would be referred to as contact dermatitis.
Irritant dermatitis (choice A) can be observed in the early stages of sensitization and can be caused
by sweating, rubbing, and residual soap. The timing of the reaction after 72 hours points to the type IV
reaction rather than an irritant dermatitis.
A type I reaction (choice B) would have been apparent within minutes with characteristic rhinitis,
conjunctivitis, urticaria, asthma, angioedema, or anaphylaxis immediately after wearing latex gloves.
A type II reaction (choice C) is a cytolytic response mediated by an antibody. The type II reaction is
observed in the context of hemolytic anemias, thrombocytopenia, and neutropenia.
A type III reaction (choice D) is an immune-complex response that sets into motion an inflammatory
response.
105. What is the explanation for an older person having a fainting spell with a resting blood
pressure of 130/60 mm Hg and a pulse reading of 40 beats per minute?
A. Aortic valve obstruction
B. Cardiac tamponade
C. Complete heart block
D. Heart failure
E. Hypertension
The correct answer is C. In complete (third degree) heart block, the ventricles beat independently of
SA node activity and P waves become completely dissociated from QRS-T complexes. The rate of the
ventricular beat is usually 30-45 per minute. Because resting cardiac output (CO) is normal and
because CO = stroke volume x heart rate, the stroke volume is increased in complete heart block.
When the stroke volume increases, a greater amount of blood must be accommodated in the arterial
tree with each heartbeat, which causes a greater increase and decrease in pressure during systole
and diastole. Note that the pulse pressure is 70 mm Hg (normal pulse pressure is 30-50 mm Hg).
The pulse pressure is decreased in aortic valve obstruction (choice A), cardiac tamponade (choice
B), heart failure (choice D). This is clearly not hypertension (choice E).
106. A well-behaved toddler, accompanied by his parents, presents with multiple fractures,
humpback and blue sclera. What is the probable diagnosis?
A. Child abuse
B. Ehlers- Danlos syndrome
C. Osteogenesis imperfecta
D. Scurvy
The correct answer is choice C. Osteogenesis imperfecta, also known as Brittle bone disease, is
characterized by retarded wound healing. . The most common form is autosomal dominant with
abnormal collagen type 1 synthesis due to a mutation in the collagen gene.
Choice A- Child abuse is unlikely in this well-behaved toddler with no other signs and symptoms of
abuse. Blue sclera are also typical of osteogenesis imperfecta, and not related to child abuse.
Choice B- Mutation in the collagen gene and lysine hydroxylase gene results in hyperextensible,
fragile skin, hypermobile joints, dislocations, varicose veins, ecchymoses, and arterial intestinal
ruptures. Inheritance varies. There are 10 types with any one of several enzyme deficiencies.
Choice D- Scurvy is characterized by anemia, petechiae, ecchymoses, bleeding gums, loose teeth,
poor wound healing and poor bone development. Deficient hydroxylation of collagen due to vitamin C
deficiency results in defective connective tissue.
107. When a histologic section is taken of an intraoral abscess, many of the observed
neutrophils show a degenerative change in which the nucleus has undergone fragmentation.
This process is known as
A. caseous necrosis
B. coagulative necrosis
C. karyolysis
D. karyorrhexis
E. pyknosis
The correct answer is D. Karyorrhexis refers to a pattern of nuclear degradation in which a pyknotic
or partially pyknotic nucleus undergoes fragmentation followed by complete lysis. This pattern is
common in the neutrophils present in acute inflammation.
The type of necrosis seen in an abscess is liquefactive necrosis. Caseous necrosis (choice A) is
seen in tuberculosis and some other granulomatous diseases; coagulative necrosis (choice B) is
seen following infarctions of many organs (other than the brain).
Karyolysis (choice C) is also a degenerative change affecting nuclei. In this case, however, it is seen
as a decrease in nuclear basophilia, which is presumably the result of DNAse activity.
Pyknosis (choice E) is characterized by nuclear shrinking and basophilia, apparently as a result of
DNA condensation.
108. If hypocalcemia is noted, excessive secretion of which of the following hormones MOST
likely contributed to hand and forearm bone erosion and resorption during chronic renal
failure?
A. Aldosterone
B. Calcitonin
C. Parathyroid hormone
D. Renin
E. Vitamin D
The correct answer is C. In renal failure, the ability of the kidney to secrete phosphate is impaired.
The resultant hyperphosphatemia causes hypocalcemia and triggers excretion of large amounts of
parathyroid hormone. The released parathyroid hormone is a major contributor to bony changes (e.g.,
osteitis fibrosa, a form of localized bone resorption) seen with chronic renal failure. Note that excess
parathyroid hormone normally causes hypercalcemia, but calcium resorption still cannot bring calcium
levels back to normal.
Aldosterone (choice A) is a regulator of serum sodium.
Calcitonin (choice B) levels are usually low in chronic renal failure unless the parathyroids have so
hypertrophied as to cause "tertiary hyperparathyroidism" with hypercalcemia.
Renin (choice D) is normally secreted by the kidney and may be decreased or increased in varying
stages and forms of kidney disease. Renin regulates blood pressure and aldosterone secretion, rather
than bone metabolism.
The active form of vitamin D (choice E), cholecalciferol, is formed in the kidney from vitamin D
absorbed from the gut and then processed by the liver. Uremia interrupts this pathway and
consequently causes a functional vitamin D deficiency.
109. Which of the following would be MOST likely present on a biopsy of a thyroid gland and
associated tissues that has a woody hardness when palpated but the needle biopsy shows no
evidence of malignancy?
A. Marked fibrous reaction with gland destruction
B. Masses of hyperplastic follicles
C. Multinucleated giant cells
D. Small foci of lymphocytic infiltration
E. Prominent lymphocytic infiltrate with gland destruction
The correct answer is A. With Riedel's thyroiditis, an uncommon form of chronic (possibly
autoimmune) thyroiditis that is characterized by dense fibrosis that destroys the thyroid gland and also
extends into the adjacent muscle and connective tissue of the neck. The condition is clinically
important because it may mimic malignancy. A key to the diagnosis is the woody hardness of fibrosis.
All other choices are likely to be swollen and soft by palpation.
Masses of hyperplastic follicles (choice B) are a feature of multinodular goiter.
Multinucleated giant cells (choice C) are a feature of de Quervain thyroiditis.
Lymphocytic infiltration (choice D) is a part of many thyroid diseases, but is seen in isolation in
subacute lymphocytic thyroiditis.
Sheets of lymphocytes with gland destruction (choice E) are seen in Hashimoto's thyroiditis.
110. Which of the following gastrointestinal diseases is most likely to be associated with
megaloblastic anemic who has been found to be deficient in vitamin B12, while the levels of all
other essential vitamins are within normal limits?
A. Atrophic gastritis
B. Celiac sprue
C. Duodenal ulcer
D. Ulcerative colitis
E. Zollinger-Ellison syndrome
The correct answer is A. An important cause of vitamin B12 deficiency is pernicious anemia
(megaloblastic), an autoimmune disease associated with atrophic gastritis. In atrophic gastritis, the
gastric epithelium undergoes intestinal metaplasia, replacing gastric chief and parietal cells with
goblet cells. The metaplastic epithelium produces insufficient intrinsic factor to bind the dietary vitamin
B12deficiency.
Celiac sprue (choice B) is a condition associated with weight loss, flatulence, greasy stools, and
increased fecal fat. Clinical improvement is seen with a gluten-free diet (a diet free of wheat, rye,
barley, and oats).
Duodenal ulcers (choice C) may also produce iron deficiency anemia because of chronic blood loss.
They are caused by damage to the duodenal epithelium by gastric acids and are associated with
cirrhosis, COPD, chronic renal failure, and hyperparathyroidism.
Ulcerative colitis (choice D) is an inflammatory bowel disease almost entirely restricted to the large
intestine. It usually causes intestinal distress and diarrhea, and it may produce a malabsorption
syndrome that includes vitamin B12deficiency.
Zollinger-Ellison syndrome (choice E) is caused by gastric acid hypersecretion leading to peptic ulcer
disease. Diarrhea is common.
111. If left untreated, severe squamous dysplasia on a vocal cord of a hoarse smoker may
progress to which of the following?
A. Adenocarcinoma
B. Lymphoepithelioma
C. Mucoepidermoid carcinoma
D. Squamous cell carcinoma
E. Squamous papilloma
The correct answer is D. Squamous cell carcinoma is the most frequent type of cancer of the larynx.
As with squamous cell carcinoma of the uterine cervix, the development of laryngeal carcinoma is
related to an orderly sequence of morphologic changes. These begin with epithelial hyperplasia,
proceed through increasingly severe degrees of dysplasia up to in situ carcinoma, and culminate with
invasive carcinoma. Cigarette smoking is the most important risk factor for the development of
laryngeal carcinoma. Any patient over the age of 50 years with hoarseness that has persisted beyond
2-3 weeks should be evaluated by indirect laryngoscopy. Odynophagia, hemoptysis, weight loss,
referred otalgia, vocal cord immobility and cervical adenopathy suggest more advanced disease.
Adenocarcinoma (choice A) and mucoepidermoid carcinoma (choice C) are rare forms of laryngeal
cancer. Squamous dysplasia is not a precursor of either type of tumor.
Lymphoepithelioma (choice B) is a form of squamous cell carcinoma that most frequently occurs in
the nasopharynx, although it has been reported in the larynx also. Its name is derived from the fact
the tumor is rich in lymphocytes. This tumor occurs frequently in southern China and certain regions in
Africa. Epstein-Barr virus is implicated in its pathogenesis.
Squamous papilloma (choice E) is a benign laryngeal neoplasm caused by human papillomavirus
types 6 and 11. It is not associated with squamous dysplasia.
112. What is the BEST explanation for the significant elevation of liver enzymes, ammonia, and
hypoglycemia experienced five days after the onset of chicken pox in a child that was given
aspirin for fever-control?
A. Crigler-Najjar syndrome
B. Dubin-Johnson syndrome
C. Gilbert's syndrome
D. Reye's syndrome
E. Rotor's syndrome
The correct answer is D. The use of aspirin in a child with chicken pox can cause Reye's syndrome.
Reye's syndrome (fatty liver with encephalopathy) is an acute (and potentially fatal) postviral injury
that is characterized by severe mitochondrial damage affecting the liver, brain, skeletal muscle, heart,
and kidneys. The rapidly progressive hepatic failure and encephalopathy is associated with a 30%
fatality rate. Most are children, although adult cases have been described. Varicella and influenza A
and B are the most common precipitating illnesses. Aspirin use has been linked to the development of
this disorder, but cases occur in the absence of salicylate ingestion. Hypoglycemia, elevated serum
aminotransferases and blood ammonia, prolonged prothrombin time, and change in mental status all
occur within 2-3 weeks after onset.
Crigler-Najjar (choice A) syndrome is a rare, mild to severe form of inherited unconjugated
hyperbilirubinemia.
Dubin-Johnson syndrome (choice B) is an inherited conjugated hyperbilirubinemia associated with a
darkly pigmented liver.
Gilbert's syndrome
(choice
C)
is
a
common,
benign
form
of
inherited
unconjugated
hyperbilirubinemia.
Rotor's syndrome (choice E) resembles Dubin-Johnson syndrome, but is associated with a normal-
colored liver.
Although most of these other symptoms are rare, it is important to recognize the signs, symptoms,
and causes of Reye's syndrome.
113. Which of the following is the MOST likely the reason for persistent and marked anasarca
noted with jaundice?
A. Lymphatic obstruction
B. Reduced central venous pressure
C. Reduced plasma oncotic pressure
D. Sodium retention
E. Venous thrombosis
The correct answer is C. Hepatic failure occurring in cirrhosis reduces the capacity of the liver to
synthesize sufficient quantities of plasma proteins (mostly albumin) necessary to maintain plasma
oncotic pressure. Low plasma oncotic pressure allows fluid from the intravascular fluid component to
move into the interstitial space, producing plasma volume contraction and edema.
Lymphatic obstruction (choice A) occurs as a result of mechanical blockage of lymphatics by tumor,
inflammatory processes, or certain parasitic infections. Cirrhosis does not lead to lymphatic
obstruction.
Reduced central venous pressure (choice B) does not cause edema. Conversely, increased central
venous pressure, which may arise with congestive heart failure, thrombosis, or cirrhosis can lead to
increased hydrostatic pressure and edema.
Sodium retention (choice D) is an important cause of edema in patients with poor renal perfusion.
The kidneys respond by retaining sodium and increasing plasma volume in an effort to increase renal
blood flow. Any sodium retention in cirrhosis is secondary to the decrease in plasma oncotic pressure
and consequent decrease in plasma volume.
Venous thrombosis (choice E) can lead to edema; however, the diminished synthesis of coagulation
proteins in cirrhosis predisposes to bleeding, not thrombosis.
114. What of the following is characterized by left lower quadrant periumbilical pain in an
elderly person, with the presence of fever, tender abdomen, leukocytosis, nausea, and
vomiting?
A. Acute appendicitis
B. Diverticulitis
C. Gallstones
D. Pancreatitis
E. Pyelonephritis
The correct answer is B. Diverticulitis is a disease of the elderly and usually involves the distal
colon. In severe cases, however, the diverticula may extend throughout the colon and up to the
cecum. Inflammation of a cecal diverticulum can closely mimic acute appendicitis. The essentials of
diagnosis for diverticulitis are acute abdominal pain and fever, left lower abdominal tenderness, and
mass. Leukocytosis is commonly present together with nausea and vomiting.
Acute appendicitis (choice A) is usually a disease of young adults (and sometimes children). It is
rarely seen in the elderly.
Pancreatitis (choice D), pyelonephritis (choice E), and gall bladder disease (choice C), refer pain to
the mid back, lateral back, and right upper quadrant, respectively.
115. Which of the following would most likely be associated with Type A chronic gastritis
resulting from autoimmune destruction of parietal cells?
A. Decreased growth of luminal bacteria
B. Decreased likelihood of developing gastric carcinoma
C. Decreased plasma concentration of gastrin
D. Increased production of macrocytic red blood cells
E. Increased secretion of pancreatic bicarbonate
The correct answer is D. Autoimmune destruction of parietal cells would lead to decreased secretion
of gastric acid and intrinsic factor. The diminished availability of intrinsic factor would result in poor
absorption of dietary vitamin B12. Over time, the vitamin B12 deficiency could lead to pernicious
anemia, which is characterized by increased production of macrocytes (megaloblasts) by the bone
marrow.
Because of the decrease in gastric acid secretion, luminal bacteria (choice A) would most likely
exhibit increased (not decreased) growth. One of the functions of HCl secreted by the parietal cells is
to sterilize the gastric lumen.
Patients with Type A gastritis have an increased likelihood of developing gastric carcinoma (not
decreased, choice B).
A decrease in acid secretion leads to increased secretion of gastrin (not decreased, choice C) by
antral G cells. This is because low gastric pH (less than 3.0) inhibits gastrin secretion by way of
paracrine release of somatostatin from cells in the gastric mucosa that can sense the acidity. With
decreased parietal cells, the pH of the gastric lumen would rise and remove this inhibitory component.
Because less acid would be delivered to the duodenum with parietal cell destruction, less secretin
would be released into the blood. This would result in decreased pancreatic bicarbonate secretion
(not increased, choice E).
116. What is present in an older woman when there is increased serum levels of calcium and
urinary cAMP levels, below normal levels of serum phosphate, and no other complaints but
weakness?
A. A calcitonin-secreting tumor
B. Primary hyperparathyroidism
C. Primary hypoparathyroidism
D. Thyrotoxicosis
E. Vitamin D deficiency
The correct answer is B. Primary hyperparathyroidism is often asymptomatic and only incidentally
discovered during routine blood work, however, there may be vague complaints of fatigue or
weakness and constipation. These neuromuscular manifestations are caused by the hypercalcemia
that can "hyperstabilize" excitable tissue membranes and reduce normal responsiveness. Primary
hyperparathyroidism incidence increases greatly after age 50 years, and is more common in women
than men. The hypercalcemia is caused by the excess plasma concentration of parathyroid hormone
(PTH). Approximately 80% of cases are caused by a single adenoma in a parathyroid gland. In the
other 20% of cases, the hypersecretion of PTH is caused by hyperplasia in multiple parathyroid
glands. The increased PTH also causes renal excretion of phosphate, producing hypophosphatemia.
PTH acts by increasing cAMP formation in target tissues. The cAMP formed in renal tubules can
diffuse into the lumen and be measured in the urine.
Tumors that secrete calcitonin (choice A) include medullary carcinoma of the thyroid and occasionally
small and large cell carcinomas of the lung. Despite calcitonin's high blood concentration, serum
phosphate is rarely abnormal and calcium levels would decrease rather than increase.
Primary hypoparathyroidism (choice C), which is caused by decreased secretion of PTH, is
associated with hypocalcemia and hyperphosphatemia. Furthermore, urinary cAMP concentration
would be decreased. The low calcium in extracellular fluid "destabilizes" excitable tissue membranes
and can lead to spontaneous action potentials that produce tetany.
Thyrotoxicosis (choice D) or hyperthyroidism is associated with sweating, anxiety, heat intolerance,
irritability, fatigue, muscle weakness, tachycardia, and warm moist skin. With vitamin D deficiency
(choice E), serum calcium is decreased because of diminished absorption from the diet. PTH
secretion is increased to compensate, resulting in bone demineralization (osteomalacia).
117. If there is a large retinal detachment in the right eye and nothing noted in the left, how do
the eyes react to a pupillary light reflex examination?
A. Constriction of the right pupil and constriction of the left
B. Constriction of the right pupil and dilatation of the left
C. Dilatation of the right pupil and constriction of the left
D. Dilatation of the right pupil and dilatation of the left
E. No reaction of the right pupil and constriction of the left
The correct answer is D. The eyes are exhibiting the Marcus-Gunn phenomenon. When light strikes
the retina, the pupillary light reflex is automatically triggered, leading to simultaneous constriction of
both pupils. In the absence of adequate light entering the eye, for example, following retinal
detachment or optic neuritis, paradoxic dilatation of the pupils occurs. The retina receives far less light
than it normally would, and the pupils dilate to absorb as much light as possible.
118. Which of the following findings is particularly indicated with a marked elevation in serum
C-reactive protein?
A. Developing autoimmune reaction
B. Ineffective immune response
C. Respiratory compromise
D. Nonspecific inflammation
The correct answer is D. C-reactive protein is one of the most commonly measured acute-phase
reactants, which are a group of serum proteins showing a rapid increase in concentration in response
to any inflammatory process. This finding is entirely nonspecific. It only indicates a recent
inflammatory process. C-reactive protein would be expected to be elevated following a dental
procedure and in cases of pharyngitis (viral and bacterial).
An autoimmune reaction (choice A), which is certainly a concern with streptococcal pharyngitis, is
suggested by the development of a rising ASO (antistreptolysin O) titer weeks after the illness. Acute
phase reactants are not specific to autoimmune processes.
Increases in C-reactive protein indicate a healthy immune response to an infective pathogen. An
ineffective immune response (choice B) would not elicit acute-phase reactions.
Respiratory compromise (choice C) produces changes in arterial blood gases and blood pH. Acute-
phase reactants do not reflect respiratory status.
119. Which of the following is characteristic when there is a blood pressure of 165/95 mm Hg,
tiredness, muscle weakness, polydipsia, while plasma sodium and serum aldosterone is
slightly increased and plasma potassium and plasma renin activity is significantly decreased?
A. Addison's disease
B. Conn's syndrome
C. Cushing's syndrome
D. Type 1 diabetes mellitus
E. Pheochromocytoma
The correct answer is B. Conn's syndrome, or primary hyperaldosteronism, results from an adrenal
tumor that secretes excessive aldosterone. The increased mineralocorticoid effects of aldosterone
lead to renal sodium and water retention (which explains the hypertension) and increased renal
potassium excretion (hypokalemia). The volume expansion also explains the decrease in hematocrit.
The increased blood volume, increased blood pressure, and hypernatremia all tend to suppress renin
secretion in an attempt to compensate for the increased aldosterone.
Addison's disease (choice A), or primary adrenal insufficiency, is characterized by low plasma
concentration of aldosterone, hyponatremia, hypotension, and hyperkalemia.
In Cushing's syndrome (choice C), blood pressure may be increased because of crossover
mineralocorticoid activity of the increased plasma cortisol. Furthermore, cortisol makes blood vessels
more responsive to catecholamines, which could increase peripheral resistance. The combination of
increased blood pressure and hypokalemia would, if anything, tend to suppress secretion of
aldosterone.
Type 1 diabetes mellitus (choice D) is associated with polyuria, polydipsia, muscle weakness, and
chronic tiredness. Renin and aldosterone levels are normal.
Pheochromocytoma (choice E) is another endocrine cause of hypertension. The increased plasma
concentration of catecholamines can cause increased cardiac output and increased peripheral
resistance. Plasma renin activity may be increased because of increased beta receptor activation on
juxtaglomerular cells. This could produce increased aldosterone secretion and subsequent salt
retention.
120. Which of the following BEST describes the inflammatory response that occurs upon
contact with certain plants and presents as a weeping, vesicular, erythematous, and itchy rash
on exposed arms, legs, neck, and face?
A. Erythema nodosum
B. Pemphigus
C. Psoriasis
D. Spongiotic dermatitis
E. Urticaria
The correct answer is D. Spongiotic dermatitis (intracellular edema of the epidermis) is seen in with
contact dermatitis, such as poison ivy exposure. The accumulation of inflammatory cells in the
superficial dermis causes marked edema, which splays epidermal keratinocytes apart and gives a
spongy appearance to intercellular bridges. Grossly, the skin has a weepy appearance with frequent
blistering. Erythema nodosum (choice A) is a form of panniculitis, which is chronic inflammation in the
subcutaneous fat lobules. Erythema nodosum presents as painful erythematous nodules, often with
fever and malaise. It is associated with infections and drug reactions and is not a contact dermatitis.
Pemphigus (choice B) is a genetic blistering disorder caused by the production of antibodies to the
intercellular cement substances in skin and mucous membranes. Psoriasis (choice C) is a common
chronic inflammatory disease causing plaques and scales, typically on elbows, knees, and scalp. The
pathogenesis of psoriasis is still unclear; it may be a complement-mediated autoimmune process.
Urticaria (choice E) is an IgE-driven hypersensitivity process. Urticaria is characterized by wheals
(edematous pruritic plaques) and typically affects the trunk and distal extremities.
