Dermato- us

A 65-year-old man comes to the office and complains of pain and a rash with blisters over the left side of his chest. He has experienced pain over the area for the past 2 days. This morning, he noticed blisters while changing his shirt. He also complains of malaise and headache. His pulse is 82/min, blood pressure is 140/90 mmHg, respirations are 14/min and temperature is 36.8C (98.4F). Physical examination reveals grouped, tense vesicles arranged in a band along the left side of his chest. Which of the following is the most likely etiology of his condition?

A 65-year-old man comes to the office with a six-month history of a non-healing ulcer on his right forearm. Physical examination demonstrates a scaling plaque with central ulceration and 1.5 cm diameter. The biopsy shows polygonal cells with atypical nuclei at all levels of the epidermis with zones of keratinization. What is the single most important risk factor for this condition?

A 62-year-old woman comes to the office for evaluation of a pigmented lesion on her left forearm. The lesion occasionally itches but is otherwise asymptomatic. She admits that she only came because her daughter had persuaded her to do so. On examination, there is a slightly elevated, brown-colored lesion measuring 7 mm in diameter with irregular borders. What is the best next step in management?

A 17-year-old white male presents to your office because the "spots" on his face "got so much worse recently!" He has several months history of acne. He has not visited a doctor before. Inspection reveals multiple papules with several pustules and nodules. Atrophic scars are seen. What is the best next step in the management of this patient?

A 35-year-old Caucasian male with aplastic anemia undergoes bone marrow transplantation. The donor is an HLA-matched sibling. Two weeks after the procedure, he develops a maculopapular pruritic rash that is predominantly found on his face, hands, and feet. He also complains of diarrhea. The stool is positive for occult blood. Liver function tests are abnormal. Which of the following is the most likely pathophysiologic mechanism of this patient's condition?

A 36-year-old male AIDS patient comes in due to a painful red eye. He complains of pain, discharge and redness in his left eye for the past 10 days. On physical examination, you notice redness in his left eye as well as multiple skin lesions on his face, left eyelid, inner thighs, penis and pubis. The lesions are painless, pale, shiny, dome-shaped papules with a central umbilication measuring 2-5mm in diameter. These lesions were not present on his previous visit. His CD4 count thirty days ago was 100/uL. What is the most likely etiology of this patient's skin lesions?

A 50-year-old man comes in for his annual check-up. There is a swelling on his left eyelid, which he casually acknowledges by saying that it has appeared "on-and-off for the past 2 years." It initially starts as a painful lesion which regresses with hot compresses, but then eventually reappears. On examination of his left eye, you note a nodular, painless, rubbery lesion on the eyelid without any discharge, redness or other abnormalities. What is the best next step in the management of his eye lesion?

A 47-year-old woman presents to your office complaining of two days of pain and itching over her left chest. Her medical history is significant for breast cancer for which she underwent a left-sided mastectomy six months ago. She has also been receiving chemotherapy and radiation. Physical examination reveals erythema around the mastectomy scar, with excoriations and occasional vesicles. Which of the following is the best treatment for her condition?

A 25-year-old woman comes to the office for the evaluation of pale patches of skin around her mouth. She noticed these lesions a few months ago, but they have become more prominent now. There is no itching, burning, or numbness over the patches. Her vital signs are stable. On examination, you notice pale white patches symmetrically distributed around her mouth. The borders of these macules are well-circumscribed and hyperpigmented. Similar lesions are also found over the areola of her breasts. She denies any history of trauma or infection. Which of the following best explains the pathology of her condition?

An 8-year-old boy is brought to the office by his mother for a routine check-up. He has fair skin, blond hair and blue eyes. His past medical history is insignificant. His mother wants to know what the best possible photo-protection is for her son, because "his skin has always been sensitive to the sun, and he is almost unable to tan." He had two episodes of sunburn recently. Physical examination reveals several junctional nevi. Which of the following is the best response to this patient's mother?

A 60-year-old male farmer presents to the office for the evaluation of a slightly painful ulcer on the top of his lower lip. The ulcer has not healed since he first noticed it three months ago. He has always been healthy and denies any sexual activity during the past year. He is afebrile. Physical examination shows a 3x7 mm, partially encrusted ulcer in the vermilion zone near the moist line (mucocutaneous junction) of the lower lip, surrounded by a 6 x 12 mm area of induration. There are no palpable submental or submandibular lymph nodes. The remainder of the physical examination is unremarkable. Complete blood count and differential are normal. Biopsy of the ulcer will most likely to show:

An 18-year-old girl comes to the emergency department for sudden-onset redness and swelling of her skin over exposed areas. She had just spent 1 hour at the beach when she began to experience a burning sensation, followed by redness and swelling of those areas. Her face has a few inflammatory nodules as well as open and closed comedones, and she was recently prescribed "some medication for the past month or so" for her facial lesions. Her pulse is 82/min, blood pressure is 120/80 mmHg, respirations are 14/min and temperature is 37.2C (99F). On examination, you notice erythema, edema and vesicles on her face, neck, dorsal hands and upper chest. She has no mucosal lesions. Which of the following best explains her condition?

A 55-year-old man comes to the office due to a sudden onset of blisters all over his body. He complains of pain in the involved areas. He first noticed the lesions in his mouth a few days ago. His pulse is 82/min, blood pressure is 140/90 mm Hg, respirations are 14/min, and temperature is 36.8C (98.4F). On examination, there are crops of flaccid bullae over normal-appearing skin, and large erosions at sites where the bullae had ruptured. The oral mucosa shows erosions and ulcerations. Slight rubbing of the uninvolved skin causes easy separation of the epidermis. Immunofluorescence microscopy shows deposits of IgG intercellularly in the epidermis. What is the most likely diagnosis?

A 45-year-old woman comes to the office for the evaluation of reddened areas over her face (flushed skin). These areas worsen every time she drinks something hot or goes out in hot, sunny weather. Her vital signs are stable. On examination, there is evident erythema over her nose, cheeks, forehead and chin with telangiectasias, pustules and papules. What is the most likely diagnosis?

A 30-year-old female presents with a circumferential pruritic rash over her right wrist. The rash has been present for the last two days, and she denies ever having a similar rash before. She bought a new bracelet two weeks ago, and has been wearing it on her right forearm since. Which of the following metals in jewelry is most likely to cause such symptoms?

A 28-year-old Caucasian woman presents to the primary care physician with complaints of painless blistering on the backs of her hands, accompanied by an increased fragility of the surrounding skin. She first noted the blisters one week ago, after spending some time gardening outdoors. She denies ever having similar symptoms, but suspects that her mother may occasionally have had a similar presentation that eventually resolved without treatment. Her past medical history is significant for chronic infection with Hepatitis C virus. Current medications include oral contraceptives, which were begun last month. Physical examination reveals mild hyperpigmentation of the face. Which of the following is the most likely diagnosis?

A 34-year-old Caucasian female presents to the ER with a rash and pruritis. She says that she has had a sore throat for several days, and her friend gave her amoxicillin that turned out to be out dated. The rash developed about 30 minutes after she took the drug. Her blood pressure is 110/70 mmHg and heart rate is 80/min. Physical examination reveals wide spread urticaria and excoriations. Pharyngeal mucosa and tonsils are hyperemic, and tender lymph nodes are palpated in the submandibular area. Lungs are clear on auscultation. Which of the following is the best next step in the management of this patient?

A 36-year-old male presents to clinic complaining of a pruritic eruption on his forearms. He denies fever, chills and malaise. Physical examination reveals an erythematous rash with occasional vesicles affecting both forearms. No lymphadenopathy is appreciated. Vesicular fluid grows coagulase- negative staphylococci. His only relevant history is recent work in the woods behind his home chopping and transporting firewood. Which of the following is the most likely diagnosis?

A 64-year-old female presents with complaints of lesions over her breasts and thighs. She had been experiencing severe pain in those areas prior to developing redness and blisters. Her past medical history is significant for valvular heart disease with atrial fibrillation, ulcerative colitis diagnosed 20 years ago, and a resection of part of her colon. She is a known patient of yours, and four days ago, you started her on treatment for atrial fibrillation with antiarrhythmics and oral anticoagulants. Her pulse is 82/min, blood pressure is 140/90 mm Hg, respirations are 14/min, and temperature is 36.8C (98.4F). On examination, you notice well-demarcated lesions with bullae and necrotic changes over her thighs and breasts. What is the most likely diagnosis?

A mother brings her 6-month-old infant to your office for evaluation of scaly, erythematous lesions around his eyebrows and sides of his nose. She also notes a scaly scalp that improves with baby shampoo. Which of the following is the most likely diagnosis?

An 83-year-old man is brought to the office by his wife because he has had frequent falls for the past 3 months. The wife says that, "He's not his usual self these days. He needs help with everything, even everyday things." The patient has mask-like facies. He speaks very softly with a poorly modulated voice, and he has a fine tremor in both hands. The resting tremor in his hands disappears with voluntary movements. The other pertinent findings include a shuffling gait with short steps, stooped posture, tendency to fall and rigidity of both upper limbs. What skin condition is associated with this patient's neurologic diagnosis?

A 43-year-old woman comes to the office because she has "finally decided to see a doctor." For the past four months, she has suffered from itching all over her body. She is tired of using over-the- counter products with no relief. Over the past two months, she has had loose stools, which "take forever to flush." Physical examination reveals jaundice, hepatomegaly and splenomegaly. The results of her blood work are as follows: Alkaline phosphatase 200 u/dl Bilirubin 3.3 mg/dl Anti-mitochondrial antibodies positive Which of the following benign lesions of the eye is frequently associated with this patient's condition?

A 25-year-old male comes to the office due to severe itching and burning of the skin lesions on his knees, elbows and back of his neck. He gives a history of loose stools, flatulence, weight loss of more than 10 lbs, and fatigue for the past 6 months. His vital signs are stable. On examination, there are papules and vesicles over the extensor aspect of his elbows, knees, posterior neck and scalp. The laboratory studies reveal the presence of anti-endomysial antibodies. Which of the following is the most likely diagnosis?

A 36-year-old male comes to the office for the evaluation of a skin lesion. For the past two months, he noticed darkening and thickening of the skin over his neck and groin area. These areas occasionally feel itchy. His pulse is 82/min, blood pressure is 130/80 mm Hg, respirations are 14/min, and temperature is 36.8C (98.4F). Physical examination reveals symmetrical, hyperpigmented, velvety plaques on the axilla, groin and posterior neck. This patient's condition should alert the physician to check for which of the following?

A 35-year-old white male presents with high-grade fever, chills, rigors, malaise, and pain in his right calf for the last 24 hours. His temperature is 39.5C (103.1F), pulse is 105/min, blood pressure is 130/80 mmHg, and respirations are 15/min. Physical examination shows generalized swelling of the calf with linear streaks of erythema. The lesion is warm, tender, and not very well-demarcated. No pain is felt in the calf when the ankle is dorsiflexed. Scaling is found in the toe webs on the right side, and KOH preparation of these lesions show hyphae. Blood cultures are obtained. CBC shows a WBC count of 14,000 with 6% bands. What is the most appropriate next step in management?

A 17 -year-old man presents with a non-pruritic rash in his periumbilical area. The rash consists of firm, dome-shaped, flesh-colored papules with central umbilication. This patient's rash is most commonly associated with which of the following conditions?

An 8-year-old boy is brought to the office due to itchy rashes with blisters over his face, trunk and legs for the past 2 days. His vital signs are normal, except for a temperature of 37.7C (100F). On examination, you notice macules, pustules, vesicles, and honey-colored crusts

An 18-year-old white female is brought to the emergency department due to severe vomiting, fever and rashes. She was fine until today, when she developed a fever, flu-like symptoms and dizziness. She has a history of asthma and allergic rhinitis. She denies taking drugs or alcohol, or being exposed to other sick individuals. She had her period yesterday, but did not place a tampon until today, 6 hours prior to becoming ill. Her last menstrual period was 6 weeks ago. She appears alert but listless. Her temperature is 38.8 C, pulse is 120/min, respirations are 23/min, and blood pressures are 100/66 mm Hg, supine and 66/30 mm Hg, standing. On examination, there are erythematous flat and raised rashes on her trunk and extremities. What is the most likely diagnosis?

A 9-year-old boy is brought to the office by his mother because of itching, burning and oozing skin lesions on both of his legs. The boy appears tanned. When asked if he had been spending time outdoors, he replies with great excitement that he just returned yesterday from a camping trip in the woods with his dad. Physical examination of both lower limbs reveals vesicles with erythema arranged in a linear fashion. Weepy and crusted lesions and edema are also present. What type of reaction is responsible for this boy's lesions?

An 18-month-old Caucasian boy is brought to the emergency department due to a 3-day history of fever and facial rash. His past medical history is significant for atopic dermatitis, which was diagnosed 1 week ago and treated with topical steroids. Examination reveals numerous umbilicated vesicles over erythematous skin of both cheeks. Submandibular adenopathy is present. What is the most probable diagnosis?

A 15-year-old male is brought to the emergency department due to sudden-onset difficulty breathing for the past 45 minutes. He also complains of nausea, colicky abdominal pain and a swollen face. He has been suffering from bronchitis for the past 4 days, and his condition had been improving. His mother says that he had a similar episode when he had a tooth extraction 2 year ago. On examination, there is an edematous swelling of his face including the lips, hands, arms, legs, and genitals. His pulse is 82/min, blood pressure is 120/80 mmHg, respirations are 18/min and temperature is 36.8C (984F). Which of the following best explains the pathological process of his condition?

A 28-year-old Caucasian male presents to the office with a rash on his trunk. He complains of constant itching over the area. He has no other medical problems. He denies any family history of diabetes. He currently has two sexual partners, and he does not use condoms. His pulse is 84/min, blood pressure is 120/80 mm Hg, respirations are 14/min, and temperature is 37C (98.4F). On his trunk, there are 4 circular patches with central clearing and scaly borders, measuring approximately 3- 8cms in diameter. What is the most likely diagnosis?

A 14-year-old white female presents with "spots" on her face that are "so embarrassing!" Physical examination reveals comedones with minimal inflammation. Her past medical history is insignificant. She does not smoke or consume alcohol. What is the best next step in the management of this patient?

A 30-year-old, Caucasian male comes to the office for the evaluation of some pale patches in a mottled distribution over his trunk area. He just returned from a 2-week summer vacation in the Bahamas, where he first noticed these lesions. His skin is generally well-tanned. Located over his central upper trunk area are multiple, velvety pink, pale macules, measuring approximately 4-5 mm in diameter. These lesions scale on scraping. What is the most likely diagnosis?

A 48-year-old Caucasian female presents to your office due to a small swelling on her left lower eyelid. She has worked outdoors her whole life. This swelling has been present for the past 6 months. Recently, she noticed a loss of eyelashes on her lower eyelid. On examination, there is a small nodular lesion on the lower eyelid margin. It is firm, painless, pearly and indurated. Loss of lashes on the left lower eyelid is confirmed. Which of the following is the most likely diagnosis?

A 5-month-old infant is brought to the office by his mother because of a rash on his face, hands and chest. The baby is constantly scratching these areas, and his mother is having a hard time keeping his hands away from the rash. She has tried a variety of over-the-counter products and many home remedies, as advised by her mother, but has noted no improvement. On physical examination, there are erythematous lesions on his cheeks with erosion, scaling, excoriated papules and plaques. Similar lesions are also found on his trunk, scalp and forehead. The lesions are symmetrical, and the diaper area appears spared. What is the most likely diagnosis?

A 48-year-old white male comes to the emergency department with complaints of severe pain and swelling in his left leg. He sustained an injury to his left leg while playing tennis five days ago. The pain worsened over the past 2-3 days, and is now unbearable. He also complains of flu-like symptoms. His temperature is 39C (102F), pulse is 104/min, blood pressure is 110/80 mm Hg, and respirations are 18/min. Physical examination reveals an edematous limb with purplish discoloration of the injured area, along with bullae and a serosanguineous discharge. The leg is extremely tender to touch. A scalpel incision of the skin reveals yellowish green necrotic tissues. What is the most likely diagnosis?

A 10-year-old girl with blue eyes and blonde hair is brought to the office by her mother for a routine check-up. All her immunizations are up to date. Her family history is significant for myocardial infarction in her father and schizophrenia in a maternal uncle. There is no family history of any skin malignancies. Her height is at the 60th percentile, and weight is at the 56th percentile. While you are examining her, the mother says with much concern that she saw a television program that claimed that the incidence of skin cancer is increasing dramatically. She wants to know the best way to prevent skin cancer in her daughter, especially since they live in California. What is the best advice to help prevent malignant melanoma in this child?

A 50-year-old man comes to the emergency department due to acute onset respiratory difficulty. He also has periorbital, circumoral and facial edema. Two weeks ago, he experienced chest pain, profuse sweating and anxiety, and was subsequently admitted to the cardiac intensive care unit. At that time, his ECG showed ST segment elevation and Q waves in the inferior leads. He was taken to the catheterization lab and had an angioplasty with stent done for 100% occlusion of the right coronary artery. He was discharged with the following medications: aspirin, clopidogrel, metoprolol, enalapril, simvastatin and isosorbide mononitrate. In the ED, his pulse is 102/min, blood pressure is 110/70 mmHg, respirations are 24/min and temperature is 36.8C (98.4F). Which of the following is most likely responsible for his present symptoms?

A 20-year-old woman presents with complaints of a rash for the past 2 days. She was in good health until 5-6 days ago, when she developed fever, malaise and headache. The rash first appeared on her face, and then rapidly spread to her trunk and extremities. Her pulse is 86/min, blood pressure is 110/70 mm Hg, respirations are 14/min, and temperature is 37.2C(99F). On examination, there is a pink maculopapular rash involving her face, trunk and extremities. Tender lymph nodes are palpable in the posterior auricular and posterior cervical areas. Her soft palate reveals patchy erythema. What is the most likely diagnosis?

A 4-year-old girl is brought to the office by her parents due to a red rash and blisters. Yesterday, she had a fever and was irritable. Today, she developed the rash with blisters. Her pulse is 90/min, blood pressure is 90/60 mm Hg, respirations are 14/min, and temperature is 39C (102F). On examination, there are superficial flaccid bullae and an erythematous rash diffusely distributed over her body. Nikolsky's sign is positive. Her face is edematous, and there is crusting around the mouth area. Her skin is warm and tender with exfoliation. What is the most likely diagnosis?

A 23-year-old college student comes to the office due to itching all over her body for the past 10 days. She hardly gets to sleep at night because of it. Her roommate has similar complaints. Her vital signs are stable. Physical examination reveals vesicles and pustules arranged in short, gray wavy channels on the finger webs, heels of palms, and in wrist creases. There are papules over the nipples and areola of her breasts. What is the most likely diagnosis?

A 32-year-old Asian female presents to the office with a mole on her foot that recently became darker. She has always had skin that is very sensitive to sunlight. She is unable to tan, and has had several sunburns when she did not use sunscreens. Her past medical history is insignificant. Her mother had 'a kind of skin cancer.' Physical examination reveals a dark mole with irregular borders on the left foot. Which of the following is the strongest risk factor for malignancy in this patient?

A 7-year-old girl is brought to the office by her mother due to a rash all over her body. She was apparently in good health until 4 days ago, when she developed fever, cough and eye pain. This morning, she developed a rash on her face, which later spread all over her entire body. Her pulse is 86/min, respirations are 14/min, blood pressure is 110/70 mm Hg, and temperature is 37.2C (99F). On examination, there is an erythematous maculopapular rash covering her entire body. There are small red spots with bluish specks on her buccal mucosa. What is the most likely diagnosis?

A 20-year-old woman complains of skin problems and is noted to have erythematous papules on her face with blackheads (open comedones) and whiteheads (closed comedones). She has also had cystic lesions. She is prescribed topical tretinoin, but without a totally acceptable result. You are considering oral antibiotics, but the patient requests oral isotretinoin, which several of her college classmates have used with benefit. Which of the following statements is correct?

A 25-year-old complains of fever and myalgias for 5 days and now has developed a macular rash over his palms and soles with some petechial lesions. The patient recently returned from a summer camping trip in Tennessee. Which of the following is the most likely cause of the rash?

A 17-year-old female presents with a pruritic rash localized to the wrist. Papules and vesicles are noted in a bandlike pattern, with slight oozing from some lesions. Which of the following is the most likely cause of the rash?

A 64-year-old woman presents with diffuse hair loss. She says that her hair is “coming out by the handfuls” after shampooing. She was treated for severe community-acquired pneumonia 2 months ago but has regained her strength and is exercising regularly. She is taking no medications. Examination reveals diffuse hair loss. Several hairs can be removed by gentle tugging. The scalp is normal without scale or erythema. Her general examination is unremarkable; in particular, her vital signs are normal, she has no pallor or inflammatory synovitis, and her reflexes are normal with a normal relaxation phase. What is the best next step in her management?

A 30-year-old black female has a 2-month history of nonproductive cough and a painful skin eruption in the lower extremities. She denies fever or weight loss. Physical examination shows several nontender raised plaques around the nares and scattered similar plaques around the base of the neck. In the lower extremities she has several erythematous tender nonulcerated nodules, measuring up to 4 cm in diameter. Chest x-ray reveals bilateral hilar adenopathy and a streaky interstitial density in the right upper lobe. What is the best way to establish a histological diagnosis?

A 72-year-old woman presents with pruritus for the past 6 weeks. She is careful to moisturize her skin after her daily shower and uses soap sparingly. She has never had this symptom before. The itching is diffuse and keeps her awake at night. Over this time she has lost 15 lb of weight and has noticed diminished appetite. She has previously been healthy and takes no medications. Physical examination shows no evidence of rash; a few excoriations are present. She appears fatigued and shows mild temporal muscle wasting. The general examination is otherwise unremarkable. What is the best next step in her management?

A 53-year-old female presents to the clinic with an erythematous lesion on the dorsum of her right hand. The lesion has been present for the past 7 months and has not responded to corticosteroid treatment. She is concerned because the lesion occasionally bleeds and has grown in size during the past few months. On physical examination you notice an 11-mm erythematous plaque with a small central ulceration. The skin is also indurated with mild crusting on the surface. Which of the following is true about this process?

A 39-year-old male with a prior history of myocardial infarction complains of yellow bumps on his elbows and buttocks. Yellow-colored cutaneous plaques are noted in those areas. The lesions occur in crops and have a surrounding reddish halo. Which of the following is the best next step in evaluation of this patient?

A 15-year-old girl complains of low-grade fever, malaise, conjunctivitis, runny nose, and cough. After this prodromal phase, a rash of discrete pink macules begins on her face and extends to her hands and feet. She is noted to have small red spots on her palate. What is the most likely cause of her rash?

A 17-year-old girl noted a 2-cm annular pink, scaly lesion on her back. Over the next 2 weeks she develops several smaller oval pink lesions with a fine collarette of scale. They seem to run in the body folds and mainly involve the trunk, although a few occur on the upper arms and thighs. There is no adenopathy and no oral lesions. Which of the following is the most likely diagnosis?

A 45-year-old man with Parkinson disease has macular areas of erythema and scaling behind the ears and on the scalp, eyebrows, glabella, nasolabial folds, and central chest. Which of the following is the most likely diagnosis?

A 20-year-old white man notes an uneven tan on his upper back and chest. On examination, he has many circular, lighter macules with a barely visible scale that coalesce into larger areas. Which test is most likely to establish the diagnosis?

A 33-year-old fair-skinned woman has telangiectasias of the cheeks and nose along with red papules and occasional pustules. She also appears to have conjunctivitis with dilated scleral vessels. She reports frequent flushing and blushing. Drinking red wine produces a severe flushing of the face. There is a family history of this condition. Which of the following is the most likely diagnosis?

A 25-year-old postal worker presents with a pruritic, nonpainful skin lesion on the dorsum of his hand. It began like an insect bite but expanded over several days. On examination, the lesion has a black, necrotic center associated with severe local swelling. The patient does not appear to be systemically ill, and vital signs are normal. Which of the following is correct?

25-year-old who has been living in Washington, DC, presents with a diffuse vesicular rash over his face and trunk. He also has fever. He has no history of chickenpox and has not received the varicella vaccine. Which of the following information obtained from history and physical examination suggests that the patient has chickenpox and not smallpox?

A 68-year-old man complains of several blisters arising over the back and trunk for the preceding 2 weeks. He takes no medications and has not noted systemic symptoms such as fever, sore throat, weight loss, or fatigue. The general physical examination is normal. The oral mucosa and the lips are normal. Several 2 to 3 cm bullae are present over the trunk and back. A few excoriations where the blisters have ruptured are present. The remainder of the skin is normal, without erythema or scale. What is the best diagnostic approach at this time?

A 63-year-old retired farmer presents to the clinic complaining of red scaly spots on his head for the past 9 months. Physical examination is remarkable for numerous erythematous hyperkeratotic papules and plaques. The lesions are confined to the head and forehead and have poorly defined borders. Which of the following is the most appropriate next step in management of this patient?

21-year-old female presents with an annular pruritic rash on her neck. She explains that the rash has been present for the past 3 weeks and that her roommate had a similar rash not long ago. Physical examination is remarkable for a 20-mm scaling, erythematous plaque with a serpiginous border. Which of the following is the most appropriate initial treatment for this condition?

A 34-year-old homosexual male with a history of HIV presents to the clinic complaining of a wheezing and multiple violaceous plaques and nodules on his trunk and extremities. Physical examination of the oral mucosa reveals similar findings on his palate, gingiva, and tongue. Chest x- ray is also significant for pulmonary infiltrates. What is the most likely pathogenesis of this process?