1. What is the primary function of desmosomes within the stratum spinosum?
a. Initiate apoptosis among keratinocytes in the upper layers
b. Transfer melanin from melanocytes to keratinocytes
c. Recognize foreign invaders and signal the innate immune response
d. Form intercellular attachments between keratinocytes
2. Which of the following medications is most likely to be responsible for causing a fixed drug eruption?
a. Hydrochlorothiazide
b. Tetracycline
c. Omeprazole
d. Methotrexate
3. Old World leishmaniasis is endemic in which of the following countries?
a. India
b. Brazil
c. Australia
d. Puerto Rico
4. Which of the following injectable anesthetics is an ester?
a. Prilocaine
b. Bupivacaine
c. Procaine
d. Lidocaine
5. Which of the following over-the-counter topical products is not recommended for use during pregnancy?
a. Salicylic acid
b. Minoxidil
c. Selenium sulfide
d. Benzoyl peroxide
6. Nevus of Ota generally occurs in which anatomic region?
a. Supraclavicular
b. Perioral
c. Lumbosacral
d. Periorbital
7. Ocular symptoms are common among all of the following conditions except
a. Behcet disease
b. Dermatomyositis
c. Rosacea
d. Linear immunoglobulin A disease
8. Which of the following conditions is generally the most pruritic?
a. Lichen amyloidosis
b. Lichen striatus
c. Lichen nitidus
d. Lichen spinulosus
9. Cafe au lait spots are associated with all of the following conditions except
a. Tuberous sclerosis
b. Ataxia telangiectasia
c. Incontinentia pigmenti
d. Neurofibromatosis
10. Which of the following statements most accurately describes classic Kaposi sarcoma?
a. Incidence is most common among African men.
b. Initial lesions typically present on the trunk.
c. The initial furuncles progress to eroded ulcerations.
d. Progression to disseminated disease is generally slow.
Answers
1. d. Form intercellular attachments between keratinocytes. Desmosomes are intercellular attachment plates formed by bundles of keratin. They promote mechanical coupling between the keratinocytes of the epidermis and provide resistance to physical stresses. Desmosomes are abundant in the intercellular spaces between the squamous cells of the stratum spinosum, and the spine-like appearance of these desmosomes along the cell margins is where the stratum spinosum derives its name. As the cells progress outward, desmosomes undergo proteolytic degradation, which contributes to the shedding of corneocytes during desquamation.
Kolarsick, P. A. J., Kolarsick, M. A., & Goodwin, C. (2011). Anatomy and physiology of the skin. Journal of the Dermatology Nurses' Association, 3(4), 203-213.
2. b. Tetracycline. The drugs most commonly associated with fixed drug eruption are sulfonamides, nonsteroidal anti-inflammatory drugs, barbiturates, tetracyclines, and carbamazepine. The initial manifestation of a fixed drug eruption generally develops 1-2 weeks after exposure to the responsible medication. With subsequent exposures, the eruption occurs in the same site within 24 hours. Classic fixed drug eruption appears in the form of one or a few round, sharply demarcated erythematous and edematous plaques, sometimes with a dusky, violaceous hue; central blister; or detached epidermis. The lesions can arise anywhere on the body but favor the lips, face, hands, feet, and genitalia. The lesions fade over several days and often leave postinflammatory hyperpigmentation.
Bolognia, J. L., Jorizzo, J. L., & Schaffer, J. V. (2012). Dermatology (3rd ed.). St. Louis, MO: Elsevier/Mosby.
3. a. India. Leishmaniasis is a disease caused by an intracellular protozoa parasite transmitted by the bite of a female sand fly. Old World leishmaniasis is caused by Leishmania species found in Africa, Asia, the Middle East, the Mediterranean, and India. New World leishmaniasis is caused by Leishmania species found in Central America and South America. Old World leishmaniasis produces cutaneous or visceral disease, whereas New World leishmaniasis produces cutaneous, visceral, and mucocutaneous diseases. The global incidence of leishmaniasis has increased in recent years because of increased international leisure and military-related travel, human alteration of vector habitats, and concomitant factors that increase susceptibility, such as infection with human immunodeficiency virus and malnutrition. With the exception of Australia, the Pacific Islands, and Antarctica, Leishmania species have been identified throughout large portions of the world. Although sand flies are found in the United States as far north as upstate New York and visceral leishmaniasis has been identified in foxhounds in a wide geographic distribution in the United States, virtually, no human transmission is believed to occur in most of the United States.
Stark, C. G. (2014). Leishmaniasis. Retrieved from http://emedicine.medscape.com/article/220298-overview
4. c. Procaine. Local anesthetics are structurally composed of three subunits: a hydrophobic aromatic ring, a hydrophilic amine group, and an intervening group that connects these two units. The region connecting the hydrophilic and hydrophobic units may be either an amide group or an ester group. The intermediate ester or amide linkage determines anesthetic metabolism and propensity for hypersensitivity. Ester anesthetics, which include procaine, benzocaine, tetracaine, and cocaine, are metabolized by plasma pseudocholinesterase and are excreted renally. Amide anesthetics, which include lidocaine, prilocaine, bupivacaine, and mepivacaine, are metabolized in the liver through dealkylation and hydrolysis by microsomal enzymes.
Goldsmith, L. A., Katz, S. I., Gilchrest, B. A., Paller, A. S., Leffell, D. J., & Wolff, K. (2012). Fitzpatrick's dermatology in general medicine (8th ed.). New York, NY: McGraw-Hill Medical.
Roenigk, R. K., Ratz, J. L., & Roenigk, H. H. (2007). Roenigk's dermatologic surgery: Current techniques in procedural dermatology (3rd ed.). New York, NY: Informa Health Care.
5. b. Minoxidil. There have been case reports of cardiac, neurodevelopmental, gastrointestinal, renal, and limb malformations with topical minoxidil use during pregnancy. Because there are no conclusive studies, minoxidil use is not recommended during pregnancy. Topical benzoyl peroxide is considered safe for acne and rosacea therapy during pregnancy. Interestingly, when benzoyl peroxide is absorbed by the skin, it is metabolized within the skin to benzoic acid, a food additive, and exposure to benzoic acid in the diet is greater than exposure from topical application. Although salicylism has occurred using methyl salicylate ointments and high concentrations of salicylic acid on widespread areas of hyperkeratotic skin, there are no known cases resulting from acne or wart products containing salicylic acid. It is generally accepted that the use of over-the-counter salicylic acid on localized areas for limited periods during pregnancy is considered safe. Likewise, local application of selenium sulfide for a limited period is acceptable.
Murase, J. E., Heller, M. M., & Butler, D. C. (2014). Safety of dermatologic medications in pregnancy and lactation. Journal of the American Academy of Dermatology, 70(3), 401.e1-401.e14.
6. d. Periorbital. Nevus of Ota occurs predominantly in more darkly pigmented individuals, especially Blacks and Asians. Lesions are most commonly present at birth or develop within the first year of life, although in some individuals, Nevus of Ota appears during puberty. Nevus of Ota is generally characterized by a confluence of individual macules varying from pinhead size to several millimeters in diameter, which gives an overall appearance of an irregularly demarcated, mottled patch. The coloration varies from shades of tan and brown to gray, blue, black, and purple because of the presence of melanin-producing melanocytes in the dermis. The overall lesion size may be a few centimeters, or there may be extensive unilateral or bilateral involvement. Nevus of Ota favors the distribution of the first two branches of the trigeminal nerve and typically involves the periorbital area, temple, forehead, malar area, earlobe, preauricular and postauricular areas, nose, and conjunctivae. In about two thirds of patients, there is involvement of the ipsilateral sclera. There may also be involvement of other ocular structures as well as the oral mucosa, pharynx, nasal mucosa, and tympanum.
Bolognia, J. L., Jorizzo, J. L., & Schaffer, J. V. (2012). Dermatology (3rd ed.). St. Louis, MO: Elsevier/Mosby.
7. b. Dermatomyositis. Dermatomyositis is not commonly associated with ocular symptoms. Approximately 50% of patients with linear immunoglobulin A disease have eye symptoms such as dry eyes, foreign body sensation, burning, and/or discharge. Slit lamp evaluation reveals conjunctival scarring and subconjunctival fibrosis with some secondary corneal clouding that can cause a long-term decline of vision. Ocular manifestations occur in 70%-85% of Behcet disease cases. Early eye involvement is unilateral with two thirds of patients progressing to bilateral eye disease. Up to 25% of patients with eye involvement develop blindness within 5 years of the onset of ocular symptoms. Therefore, prompt evaluation by an ophthalmologist is essential for all patients with Behcet disease. More than 50% of rosacea cases have ocular involvement, which occurs independent of skin severity. Objectively, redness and telangiectasia can be seen on the eyelid with blepharitis, hordeola, and chalazia along the eyelid margin. Patients also commonly complain of dry eyes, ocular pain, burning, and foreign body sensation. Any symptomatic eye involvement should prompt an ophthalmology referral.
Bolognia, J. L., Jorizzo, J. L., & Schaffer, J. V. (2012). Dermatology (3rd ed.). St. Louis, MO: Elsevier/Mosby.
Horner, M. E., Abramson, A. K., Warren, R. B., Swanson, S., & Menter, M. A. (2014). The spectrum of oculocutaneous disease: Part I. Infections, inflammatory and genetic causes of oculocutaneous disease. Journal of the American Academy of Dermatology, 70(5), 795.e1-795.e25.
8. a. Lichen amyloidosis. Lichen amyloidosis is characterized by the appearance of paroxysmally pruritic lichenoid papules. The primary lesions are small, brown, discrete, slightly scaly papules that group to form large, infiltrated, moniliform plaques. The most common presentation is on the bilateral shins. Less commonly, the thighs, forearms, and upper back may be affected. Treatment is often unsatisfactory and must include efforts to reduce chronic rubbing of the skin. Lichen striatus is a fairly common self-limited eruption that is seen primarily in children. Lesions begin as 1- to 3-mm papules that are erythematous and slightly scaly. These papules coalesce to form a 1- to 3-cm-wide continuous or interrupted band that, over a few weeks, progresses down the extremity or around the trunk, following the lines of Blaschko. The lesions are usually asymptomatic and last for an average of 1 year. Lichen nitidus is a chronic inflammatory disease characterized by minute, shiny, flat-topped, pale, exquisitely discrete, uniform papules that are rarely larger than a pinhead. Initially, lesions are localized, chiefly on the penis and lower abdomen, the inner surfaces of the thighs, and the flexor aspects of the wrists and forearms. The condition is usually asymptomatic, and the course is slowly progressive with a tendency for remission. Lichen spinulosus is a disease chiefly of children that is characterized by minute filiform horny spines that protrude from follicular openings independent of any papules. The spines are discrete, grouped, and symmetrically distributed over the trunk, limbs, and buttocks with a predilection for the neck, buttocks, abdominal wall, popliteal spaces, and extensor surfaces of the arms. Little or no itching is present, and the lesions tend to involute at puberty.
James, W. D., Berger, T. G., & Elston, D. M. (2011). Andrews' diseases of the skin: Clinical dermatology (11th ed.). Philadelphia, PA: Saunders/Elsevier.
9. c. Incontinentia pigmenti. Incontinentia pigmenti is an X-linked, dominant condition that appears in girls during the first weeks after birth. In most cases, vesicular and verrucous lesions occur before the onset of pigmented macules arranged in streaks, sprays, splatters, and whorls that follow the lines of Blaschko. Typical cafe au lait spots are not an expected finding in this condition. Tuberous sclerosis is an autosomal dominantly inherited condition in which affected individuals may experience adenoma sebaceum, mental deficiency, and epilepsy. Cutaneous manifestations include periungual fibromas, shagreen plaques, oral papillomatosis, ash-leaf hypomelanotic macules, skin fibromas, and cafe au lait spots. Ataxia telangectasia is a rare autosomal recessive disorder in which affected individuals experience neurologic decline that usually results in wheelchair dependency by the early teenage years. Cutaneous manifestations include telangiectasias, cafe au lait patches, hypopigmented macules, seborrheic dermatitis, premature graying, and sparsity of the hair and progeroid features. Neurofibromatosis is an autosomal dominantly inherited syndrome manifested by developmental changes in the nervous system, bones, and skin. The presence of six or more cafe au lait macules of more than 5 mm in greatest diameter in prepubertal individuals or more than 15 mm in greatest diameter in postpubertal individuals should raise suspicion for neurofibromatosis.
Bolognia, J. L., Jorizzo, J. L., & Schaffer, J. V. (2012). Dermatology (3rd ed.). St. Louis, MO: Elsevier/Mosby.
James, W. D., Berger, T. G., & Elston, D. M. (2011). Andrews' diseases of the skin: Clinical dermatology (11th ed.). Philadelphia, PA: Saunders/Elsevier.
10. d. Progression to disseminated disease is generally slow. Kaposi sarcoma (KS) is a multifocal, systemic tumor of endothelial origin that results from infection with human herpes virus 8. There are four clinical variants: classic KS, endemic African KS, KS associated with immunosuppressive therapy, and acquired-immunodeficiency-syndrome-related KS. The typical patient with classic KS is a Caucasian man in his 60s with a Mediterranean or Jewish background. The tumors usually start on the skin of the distal portions of the lower extremities as unilateral or bilateral bluish-red (hematoma-like) macules that slowly progress both horizontally and vertically and into firm plaques and eventually nodules. During the tumor's progression, the color changes to brownish, and the skin overlying the tumor becomes hyperkeratotic and may ulcerate. There is frequently pitting edema surrounding the tumor that may evolve into fibrosis. Classic KS usually runs a rather benign course, and after several years of proximal tumor progression, dissemination frequently occurs to other body sites, such as the lymph nodes, mucous membranes, and internal organs. This dissemination is rarely symptomatic, and patients may live with the slowly progressing disease for decades.
Goldsmith, L. A., Katz, S. I., Gilchrest, B. A., Paller, A. S., Leffell, D. J., & Wolff, K. (2012). Fitzpatrick's dermatology in general medicine (8th ed.). New York, NY: McGraw-Hill Medical.