Dermatology

Question 1

What is a macule? Give an example.

Answer 1

Flat spot less than 1 cm (nonpalpable, just visible)

e.g. freckles, tattoos

Question 2

What is a patch? Give an example.

Answer 2

Flat spot greater than 1 cm (nonpalpable, just visible)

e.g. port-wine birthmarks

Question 3

What is a papule? Give an example.

Answer 3

Solid, elevated lesion less than 1 cm (palpable)

e.g. wart, acne, lichen planus

Question 4

What is a plaque? Give an example.

Answer 4

Solid, elevated lesion greater than 1 cm (palpable) and flat-topped
e.g. psoriasis

Question 5

What is a nodule? Give an example.

Answer 5

Palpable, solid lesion greater than 1 cm and not flat-topped

e.g. small lipoma, erythema nodosum

Question 6

What is a vesicle? Give an example.

Answer 6

Elevated, circumscribed lesion less than 5 mm containing clear fluid (small blister)
e.g. chickenpox, genital herpes

Question 7

What is a bulla? Give an example.

Answer 7

Elevated, circumscribed lesion greater than 5 mm containing clear fluid (large blister)
e.g. contact dermatitis, pemphigus

Question 8

What is a wheal? Give an example.

Answer 8

Itchy, transiently edematous area

e.g. allergic reaction

Question 9

Define vitiligo. With what disease is it associated?

Answer 9

Skin depigmentation of unknown etiology. Associated with autoimmune conditions such as pernicious anemia, hypothyroidism, Addison’s disease, and type I DM. Patients often have antibodies to melanin, parietal cells, thyroid, or other factors.

Question 10

Name several conditions to think about in patients with pruritus.

Answer 10

Obstructive biliary disease, uremia, polycythemia rubra vera (classically after warm shower or bath)
Contact or atopic dermatitis, scabies, and lichen planus

Question 11

Define contact dermatitis. How do you recognize it? What are the classic culprits?

Answer 11

Type IV hypersensitivity reaction (though it also may be due to irritating or toxic substances). Look for new exposures to classic offending agent (e.g. poison ivy, nickel, deodorant).
Rash is well-circumscribed and occurs only in area of exposure. Skin is red and itchy and often has vesicles or bullae.

Question 12

Define atopic dermatitis. What history points to this diagnosis?

Answer 12

Chronic allergic-type condition that begins in first year of life with red, itchy, weeping skin on head, upper extremities, and sometimes diaper area. Clue to diagnosis is family +/- personal history of allergies (e.g. hay fever) and asthma.
Treatment: avoid drying soaps, antihistamines, topical steroids

Question 13

Define seborrheic dermatitis. What part of the body does it involve? How is it treated?

Answer 13

Causes cradle cap, dandruff, blepharitis (eyelid inflammation)
Scaling skin with or without erythema on hairy areas of head (scalp, eyebrows, mustache) as well as forehead, nasolabial folds, external ear canals, postauricular creases.
Treat with dandruff shampoo (selenium or tar), topical corticosteroids +/- ketoconazole cream.

Question 14

What is tinea corporis?

Answer 14

Body/trunk fungus, ringworm

Look for read ring-shaped lesions with raised borders that tend to clear centrally while they expand peripherlaly

Question 15

What is tinea pedis?

Answer 15

Athlete’s foot
Look for macerated, scaling web spaces between the toes that often itch and may be associated with thickened, distorted toenails - good foot hygiene is part of treatment!

Question 16

What is tinea unguium?

Answer 16

Onychomycosis

Thickened, distorted nails with debris under the nail edges

Question 17

What is tinea capitis?

Answer 17

Scalp fungus
Mainly affects children (highly contagious), who have scaly patched of hair loss and may have inflamed, boggy granuloma of scalp (kerion) that usually resolved on its own

Question 18

What is tinea cruris?

Answer 18

Jock itch

More common in obese males, usually found in crural folds of upper, inner thighs

Question 19

What organisms cause fungal infections?

Answer 19

Most are due to Trichophyton spp.

Question 20

In tinea capitis, if hair fluoresces under the Wood’s lamp, what is the cause? If not?

Answer 20

Microsporum spp. if fluoresces

Trichophyton spp. if not

Question 21

How are fungal infections diagnosed and treated?

Answer 21

Formal diagnosis is made by scraping the lesion and doing a potassium hydroxide (KOH) prep to visualize fungus via microscope or by culture.
Treat tinea capitis and onychomycosis with oral antifungals.
Other can be treated with topical antifungals (imidazoles such as miconazole, clotrimazole, ketoconazole) or griseofulvin, which is better for severe or persistent infection.

Question 22

True or false. Candidiasis is often a normal finding in some women and children.

Answer 22

True.
Oral thrush (cream white patches on tongue or buccal mucosa that can be scraped off) is seen in normal children and Candida vulvovaginitis is seen in normal woman (esp. in pregnancy or after taking antibiotics). 
Otherwise, may be a sign of diabetes or immunodeficiency.

Question 23

How is candidiasis treated?

Answer 23

Local/topical nystatin or imidazoles (e.g. miconazole, clotrimazole).
Oral therapy (nystatin or ketoconazole) is used for extensive or resistant disease.

Question 24

What causes scabies? How do you recognize it?

Answer 24

Mite Scarcoptes scabei, which tunnels into skin and leaves visible burrows, classically in the finger web spaces and flexor surfaces of wrists.
Facial involvement is sometimes seen in infants.
Patients also have severe pruritus and scratching can lead to secondary bacterial infection.

Question 25

How do you diagnose and treat scabies?

Answer 25

Scraping of a mite out of a burrow and viewing it under microscope.
Treat with permethrin cream applied to the whole body. Treat all contacts (whole family).
Do NOT use lindane unless premethrin is not an option. Lindane used to be treatment of choice but can cause neurotoxicity (esp. in young children).

Question 26

How do you recognize and treat tinea versicolor?

Answer 26

Also known as pityriasis versicolor is a Pityrosporum fungal infection that presents with multiple patches of various size and color (brown, tan, and white) on the torso of young adults. Often becomes noticeable in summer because affected areas fail to tan and look white.
Diagnose from lesion scrapings (KOH prep).
Treat with selenium sulfide shampoo or topical imidazoles.

Question 27

What causes lice? How are they treated?

Answer 27

Lice (pediculosis) can involve the head (Pediculus capitis; common in school children), body (Pediculus corporis) or pubic area (crabs, Phthirus pubis and transmitted sexually). Infected areas itch. Diagnosis is made by seeing lice on hair shafts.
Treat with permethrin cream and decontaminate source of reinfection (combs, hats, bed sheets, clothing).

Question 28

What causes warts? How are they treated?

Answer 28

HPV 6 and 11. Infectious and most common in older children, classically on hands.
Multiple treatments available: salicylic acid, liquid nitrogen, and curettage.
Genital warts also caused by HPV.

Question 29

Define molluscum contagiosum. How do you recognize it? How is it treated?

Answer 29

Poxvirus infection common in children but can also be transmitted sexually.
Skin-colored, smooth, waxy papules with central depression (umbilicated) that are roughly 0.5 cm.
Contents of lesion would include cells with characteristic inclusion bodies.
Treat with freezing or curettage.

Question 30

True or false: A child with genital molluscum is probably a victim of sexual abuse.

Answer 30

False. Most common mechanism is autoinoculation. Do NOT automatically assume child abuse.

Question 31

How is acne describes in medical terms? What bacteria may be partially involved in its pathogenesis?

Answer 31

Comedones (whiteheads or blackheads), papules, pustules, inflames nodules, superficial pus-filled cysts, and/or possible inflammatory skin changes including scars.
Propionibacterium acnes is thought to be involved, as is blockage of pilosebaceous glands.

Question 32

True or false: Acne is not related to food, exercise, or sex.

Answer 32

True. Acne has NOT been proven to be related to any of these (including masturbation). Cosmetics may aggravate acne.

Question 33

What are the treatment options for acne?

Answer 33

Start with topical benzoyl peroxide; then topical clindamyin, oral tetracycline, or oral erythromycin (for P. acnes eradication).
Third option is topical tretinoin; oral isotretinoin is LAST RESORT - teratogenic, may cause dry skin and mucosae, muscle and joint pain, and LFT abnormalities

Question 34

Define rosacea. In what age group is it seen? How do you treat it?

Answer 34

Looks like acne but begins in middle age. Look for rhinophyma (bulbous red nose) and coexisting blepharitis.
Treat with topical metronidazole or oral tetracycline.
Pathogenesis is not completely understood, but it is not related to diet.

Question 35

What should you think about if you see hirsutism?

Answer 35

Most commonly idiopathic but other signs of virilization (e.g. deepening voice, clitoromegaly, frontal balding) suggest androgen-secreting ovarian tumor.
In absence of virilization, consider Cushing syndrome, PCOS (Stein-Leventhal syndrome) and drugs (minoxidil, corticosteroids, and phenytoin).

Question 36

What are the common pathologic causes of baldness?

Answer 36

Trichotillomania (psych disorder in which patients pull out their hair; baldness is patchy and irregular)
Alopecia areata (idiopathic but associated with antimicrosomal and other autoantibodies)
Also SLE, syphilis, chemotherapy

Question 37

What causes ordinary male pattern baldness?

Answer 37

Considered a genetic disorder that requires androgens for expression. Not completely clear.

Question 38

Describe the classic psoriatic lesion.

Answer 38

Dry, well-circumscribed, silvery, scaling papules and plaques that are NOT pruritic. Classic lesion is found on scalp and extensor surfcaes of elbows and kness.

Question 39

What historical points and physical findings may be seen with psoriasis? How is it diagnosed and treated?

Answer 39

Family history often present, mostly occurs in Caucasians with onset in early adulthood.
Pitting of nails and arthritis that resembles RA but is rheumatoid factor-negative.
Treatment involves exposure to UV light, lubricants, topical corticosteroids, and keratolytics (e.g. coal tar, salicylic acid, anthralin).

Question 40

Give the classic description and natural course of pityriasis rosea.

Answer 40

Typically seen in young adults.
Herald patch (slightly erythematous, scaly, ring-shaped or oval patch classically seen on trunk), followed 1 week later by many similar lesions that itch. Look on back with long axis that parallels Langerhans skin cleavage lines, typically in “Christmas tree” pattern.
Remits spontaneously in 1 month. Think about syphilis in differential. Treat with reassurance.

Question 41

What are the “four Ps” that clinch a diagnosis of lichen planus?

Answer 41

Pruritic, Purple, Polygonal Papules classically on wrists or lower legs, usually of adults.
Oral mucosal lesions (whitish, with lace-like pattern) may be present.

Question 42

List the classic drugs that cause photosensitivity of the skin.

Answer 42

Tetracyclines
Phenothiazines
Birth control pills

Question 43

Describe the classic lesion of erythema multiforme. What drugs classically cause it?

Answer 43

Target (iris) lesions.

Sulfa drugs or penicillins, but herpes may also cause it. Some cases are idiopathic.

Question 44

What is the severe form of erythema multiforme called?

Answer 44

Stevens-Johnson syndrome. Often fatal because of severe, widespread skin involvement. Treat supportively.

Question 45

Describe the classic lesion of erythema nodosum. With what diseases is it commonly associated?

Answer 45

Inflammation of subcutaneous tissue and skin, classically over skins (pretibial). Look for tender, red nodules.
Sarcoidosis, coccidioidomycosis, or ulcerative colitis classically accompany this condition.

Question 46

Define and describe pemphigus vulgaris. How is it different from bullous pemphigoid?

Answer 46

Pemphigus vulgaris is autoimmune disease of middle-aged and elderly patients. Presents with multiple bullae, starting in oral mucosa and spreading to skin. Biopsy can be stained for antibody (IgG to desmoglein III - associated with desmosomes) and shows “lace-like” or “fishnet” immunofluorescence pattern. Treat with oral corticosteroids.
Bullous pemphigoid is similar but milder, resulting in linear immunofluorescence.

Question 47

What skin disease is associated with celiac disease (gluten intolerance or sensitivity)? How is it treated?

Answer 47

Dermatitis herpetiformis. Patients have intensely pruritic vesicles, papules, and wheals on extensor aspects of elbows and knees, possibly face or neck. Skin has IgA deposits even in unaffected areas.
Look for diarrhea and weight loss.
Treat with gluten-free diet.

Question 48

What are decubitus ulcers? What is the best method of prevention?

Answer 48

Bedsores or pressure sores due to prolonged pressure against skin. Best treatment is prophylaxis. Periodic turning and special air mattresses. Major skin breaks must be treated with aggressive surgical debridement.

Question 49

What conditions does excessive perspiration suggest?

Answer 49

Look for MI, TB or infection, hyperthyroidism, or pheochromocytoma

Question 50

True or false: Most melanomas start out as simple moles.

Answer 50

True. Moles are common and benign, but malignant transformation is possible.
Excise any mole if it enlarges suddenly, develops irregular borders, darkens or becomes inflamed, changes color, begins to bleed, itch, or becomes painful.

Question 51

Define dysplastic nevi syndrome. How is it managed?

Answer 51

Genetic condition with multiple dysplastic-appearing nevi (usually more than 100 moles). Look for family history of melanoma. Treat with careful follow-up, excision, or biopsy of suspicious lesions, avoid sun exposure, and sunscreen use.

Question 52

What is keratoacanthoma?

Answer 52

Can mimic skin cancer (esp. squamous cell cancer). Look for flesh-colored lesion with central crater containing keratinous material, classically on face. Has very rapid onset and grow to full size in 1-2 months (which almost never happens with SCC). Involutes spontaneously in a few months and requires no treatment.

Question 53

When and where are keloids seen?

Answer 53

Overgrowths of scar tissue after an injury; most frequent in blacks. Usually slightly pink and appear on upper back, chest, and deltoid area most commonly. Also after ear piercing. Do not excise because it may worsen scarring.

Question 54

Describe classic lesion of basal cell cancer. What should you do if you suspect it?

Answer 54

Begins as shiny papule on sun-exposed area (head is classic) and slowly enlarges and develops umbilicated center (which may ulcerate) with peripheral telangiectasias. Most common in elderly, light-skinned people. Treat with excision.

Question 55

True or false: Basal cell skin cancer almost never develops metastases.

Answer 55

True. However, it may be locally invasive and destructive.

Question 56

From what lesion does squamous cell cancer classically develop?

Answer 56

Areas with preexisting actinic keratoses (hard, sharp, red, often scaly lesions in sun-exposed areas) or burn scars. Lesions become nodular, warty, or ulcerated. Although metastases are rare, they occur more frequently than in basal cell cancer.

Question 57

What is Bowen disease?

Answer 57

Squamous cell cancer in situ

Question 58

To what parameter is the prognosis of a malignant melanoma most closely related?

Answer 58

Vertical depth of invasion into the skin

Question 59

What type of melanoma do black patients tend to develop? How do you recognize it?

Answer 59

Acrolentiginous type. Look for black dots on the palms or soles or under fingernails that start to change in appearance or cause symptoms.

Question 60

Describe Paget disease of the nipple. What is its significance?

Answer 60

Unilateral, red, oozing or crusting nipple in an adult woman that fails to respond to typical derm treatment. Though rare (1-2% of breast cancers), it signifies underlying breast cancer (usually invasive ductal carcinoma or ductal carcinoma in situ) with extension to the skin.

Question 61

Define stomatitis. What does it suggest?

Answer 61

Inflammation of mucous membranes of mouth. Classic finding is fissuring of corners of mouth (angular stomatitis).
Watch for deficiencies of B-complex vitamins (riboflavin, niacin, pyridoxine) or vitamin C.