Question: 1 A 35-year-old woman presents with a sudden onset of painful, grouped vesicles on an erythematous base, affecting the left side of her face. She also reports a prodromal phase of burning and tingling sensation in the same area. What is the most likely diagnosis? A. Herpes zoster (shingles) B. Herpes simplex virus infection C. Impetigo D. Erysipelas Answer: A Explanation: The patient's clinical presentation is consistent with herpes zoster (shingles), a viral infection caused by the reactivation of the varicella-zoster virus. Herpes zoster typically presents as painful, grouped vesicles on an erythematous base, following a dermatomal distribution. The prodromal phase of burning and tingling sensation is characteristic of herpes zoster. Herpes simplex virus infection typically presents as grouped vesicles on an erythematous base, but it is not typically dermatomal. Impetigo presents with honey-colored crusts and vesicles, commonly affecting the face. Erysipelas is a bacterial infection characterized by well-demarcated, raised, erythematous plaques with a shiny appearance. Question: 2 A 35-year-old female presents with a pruritic rash on her hands. She works as a hairdresser and has been exposed to various chemicals and frequent wet work. On examination, you observe erythematous, scaly, and fissured patches on the dorsal surfaces of her hands and fingers. There are no vesicles or bullae. Which of the following conditions is most likely to be associated with this presentation? A. Allergic contact dermatitis B. Dyshidrotic eczema C. Irritant contact dermatitis D. Tinea manuum Answer: C Explanation: The presentation described is consistent with irritant contact dermatitis. Irritant contact dermatitis occurs as a result of repeated exposure to irritating substances, such as chemicals or frequent wet work. It is characterized by erythematous, scaly, and fissured patches on the affected areas. Allergic contact dermatitis, on the other hand, is a delayed hypersensitivity reaction to a specific allergen and often presents with vesicles or bullae. Dyshidrotic eczema typically presents with vesicles or bullae on the palms, soles, or lateral aspects of the fingers. Tinea manuum, or fungal infection of the hand, may present with erythematous, scaly patches, but it is less likely in the absence of vesicles or bullae and a history of exposure to potential fungal sources. Question: 3 A 30-year-old female presents with erythematous, scaly plaques on her scalp, behind her ears, and in her retroauricular regions. She complains of itching and occasional hair loss. On examination, you observe silvery-white scales and a positive Auspitz sign. Which of the following is the most likely diagnosis? A. Psoriasis B. Seborrheic dermatitis C. Tinea capitis D. Contact dermatitis Answer: A Explanation: The clinical presentation described is consistent with psoriasis of the scalp. Psoriasis is a chronic inflammatory skin condition characterized by well-demarcated erythematous plaques with silvery scales. Scalp involvement is common and often extends to the retroauricular regions. The presence of silvery-white scales and a positive Auspitz sign (bleeding after removal of scales) are classic features of psoriasis. Seborrheic dermatitis may also involve the scalp but typically presents with greasy, yellowish scales and may involve other seborrheic areas, such as the face and central chest. Tinea capitis, or fungal infection of the scalp, may present with scaling and hair loss, but it is less likely to have the characteristic silvery-white scales seen in psoriasis. Contact dermatitis typically occurs in areas of exposure to allergens or irritants and may present with erythema, edema, and vesicles. Question: 4 A 25-year-old male patient presents with a pruritic rash on his elbows, knees, and scalp. On examination, you observe well-demarcated, erythematous plaques with silvery scales. The patient reports that his father also has a similar skin condition. What is the most likely diagnosis? A. Psoriasis B. Atopic dermatitis C. Pityriasis rosea D. Tinea corporis Answer: A Explanation: The clinical presentation described is consistent with psoriasis, a chronic autoimmune skin condition. Psoriasis commonly presents as well-demarcated, erythematous plaques with silver-white scales. It typically affects the extensor surfaces of the elbows and knees, as well as the scalp. Psoriasis has a genetic component and can run in families. Atopic dermatitis (eczema) typically presents with pruritic, erythematous patches and papules in flexural areas. Pityriasis rosea presents with oval-shaped, erythematous plaques with a collarette of scale, often following a "herald patch." Tinea corporis (ringworm) presents with circular, erythematous patches with raised borders and central clearing. Question: 5 A 35-year-old female presents with a pruritic rash on her hands and fingers. On examination, you observe erythematous papules, vesicles, and scaling involving the lateral aspects of her fingers and the web spaces. She works as a nurse and frequently washes her hands. Which of the following is the most likely diagnosis? A. Allergic contact dermatitis B. Dyshidrotic eczema C. Irritant contact dermatitis D. Scabies infestation Answer: B Explanation: The clinical presentation described is consistent with dyshidrotic eczema, also known as pompholyx. Dyshidrotic eczema is a type of eczematous dermatitis characterized by pruritic, erythematous papules, vesicles, and scaling on the lateral aspects of the fingers and in the web spaces. It iscommonly associated with frequent hand washing and exposure to irritants. Allergic contact dermatitis may present with a similar appearance but is usually localized to the areas of contact with the allergen. Irritant contact dermatitis can also present with similar findings but is typically more diffuse and involves areas exposed to irritants. Scabies infestation usually presents with burrows, papules, and excoriations in interdigital spaces, wrists, and other areas where mites burrow. Question: 6 A 65-year-old male presents with a non-healing ulcer on his lower leg. The ulcer has a punched-out appearance with undermined edges and a necrotic base. The surrounding skin shows signs of chronic venous insufficiency, including edema, hyperpigmentation, and venous stasis dermatitis. Which of the following is the most likely diagnosis? A. Pyoderma gangrenosum B. Arterial insufficiency ulcer C. Diabetic foot ulcer D. Venous stasis ulcer Answer: D Explanation: The clinical presentation described is highly suggestive of a venous stasis ulcer. Venous stasis ulcers typically occur in the lower leg, particularly around the medial or lateral malleolus, in patients with chronic venous insufficiency. They have a punched-out appearance with undermined edges and a necrotic base. The surrounding skin may exhibit signs of venous insufficiency, such as edema, hyperpigmentation, and venous stasis dermatitis. Pyoderma gangrenosum is a rare ulcerative condition characterized by painful ulcers with undermined violaceous edges. Arterial insufficiency ulcers are usually located on the lower extremities and are associated with peripheral artery disease. Diabetic foot ulcers are common in patients with diabetes and often occur at pressure points on the foot. Question: 7 A 40-year-old man presents with multiple hyperpigmented macules on his face. He reports that the lesions have been present since childhood and have remained stable in size and shape. On examination, you observe well-demarcated, light-brown macules distributed symmetrically on the cheeks, forehead, and upper lip. What is the most likely diagnosis? A. Lentigines B. Melasma C. Cafe-au-lait macules D. Post-inflammatory hyperpigmentation Answer: A Explanation: The clinical presentation described is consistent with lentigines, which are benign, well-demarcated, light-brown macules that commonly appear on sun-exposed areas. Lentigines usually emerge during childhood or early adulthood and remain stable in size and shape. Melasma presents as hyperpigmented patches on the face, often associated with sun exposure and hormonal changes. Cafe-au-lait macules are light-brown macules that may be present at birth or develop in childhood, but they are typically larger and have irregular borders. Post-inflammatory hyperpigmentation occurs following inflammation or injury to the skin, resulting in localized areas of increased pigmentation. Question: 8 A 65-year-old man presents with a solitary, pigmented lesion on his back. On examination, you observe a macule with an irregular border, variegated colors, and asymmetric shape. The lesion measures 8 mm in diameter. What is the most appropriate initial management? A. Excisional biopsy B. Shave biopsy C. Observation with serial monitoring D. Cryotherapy Answer: A Explanation: The clinical presentation described raises concern for melanoma, a potentially aggressive form of skin cancer. The most appropriate initial management for a suspicious pigmented lesion is excisional biopsy, which involves complete removal of the lesion for histopathological evaluation. Shave biopsy or observation with serial monitoring are not recommended as initial management for suspected melanoma. Cryotherapy is typically used for benign lesions or superficial non-melanoma skin cancers. Question: 9 A 50-year-old woman presents with an intensely pruritic rash on her wrists and ankles. On examination, you observe linear burrows, vesicles, and excoriations in these areas. What is the most likely diagnosis? A. Scabies B. Contact dermatitis C. Erythema multiforme D. Pemphigus vulgaris Answer: A Explanation: The clinical presentation described is consistent with scabies, a parasitic infestation caused by the Sarcoptes scabiei mite. Scabies presents with intensely pruritic linear burrows, vesicles, and excoriations, commonly affecting the wrists, hands, and interdigital spaces. Contact dermatitis may present with a rash in exposed areas, but it does not typically have the characteristic burrows seen in scabies. Erythema multiforme presents with target-like lesions with central dusky erythema and surrounding rings. Pemphigus vulgaris is an autoimmune blistering disorder characterized by flaccid bullae and erosions on the skin and mucous membranes. Question: 10 Mary Anderson, a 45-year-old woman, presents to your clinic with a complaint of a rash on her face. She reports that the rash started a few weeks ago and has been progressively worsening. On examination, you note erythematous papules and pustules, along with comedones, primarily affecting the central face, including the forehead, nose, and cheeks. There is no involvement of the nasolabial folds or periocular area. Based on the clinical presentation, what is the most likely diagnosis? A. Acne vulgaris B. Rosacea C. Seborrheic dermatitis D. Perioral dermatitis Answer: B Explanation: Rosacea is a chronic inflammatory skin condition that primarily affects the central face. The clinical presentation typically includes erythema, papules, pustules, and telangiectasias. In contrast to acne vulgaris, rosacea does not involve the nasolabial folds or periocular area. Seborrheic dermatitis typically presents with erythematous plaques with greasy scales, commonly affecting the scalp, face, and central chest. Perioral dermatitis is characterized by erythematous papules and pustules around the mouth, sparing the vermillion border. Question: 11 A 30-year-old male patient presents to your clinic with a pruritic rash on his hands. He works as a florist and frequently handles flowers and plants. On examination, you observe erythematous, vesicular lesions on the dorsal aspects of his hands and fingers. The lesions are arranged in a linear pattern. Which of the following is the most likely diagnosis? A. Contact dermatitis B. Scabies C. Dyshidrotic eczema D. Herpes simplex virus infection Answer: A Explanation: The patient's occupation as a florist and the presence of a pruritic rash on the hands suggest contact dermatitis, which is an inflammatory skin condition caused by exposure to irritants or allergens. The linear arrangement of the vesicular lesions is consistent with a contact allergen. Scabies presents with burrows, papules, and vesicles in interdigital spaces, wrists, axillae, and groin. Dyshidrotic eczema typically presents with pruritic vesicles on the palms, lateral fingers, and soles. Herpes simplex virus infection commonly presents as grouped vesicles on an erythematous base, typically affecting the mucocutaneous junctions. Question: 12 A 45-year-old male presents with a pruritic rash on the extensor surfaces of his elbows and knees. The rash consists of well-demarcated erythematous plaques with silvery scales. On examination, you also notice pitting and ridging of his nails. Which of the following conditions is most likely to be associated with this presentation? A. Psoriasis B. Atopic dermatitis C. Contact dermatitis D. Seborrheic dermatitis Answer: A Explanation: The presentation described is classic for psoriasis. Psoriasis is a chronic inflammatory skin condition characterized by well-demarcated erythematous plaques with silvery scales. The extensor surfaces of the elbows and knees are commonly affected. Nail involvement, characterized by pitting and ridging, is also common in psoriasis. Atopic dermatitis is characterized by pruritic, erythematous, and scaly patches, typically seen in flexural areas. Contact dermatitis presents as a localized rash in response to a specific allergen or irritant. Seborrheic dermatitis typically affects areas with high sebaceous gland activity, such as the scalp, face, and central chest, and is characterized by erythematous plaques with greasy scales. Question: 13 A 55-year-old male presents with a non-healing ulcer on his lower leg. The ulcer is irregularly shaped with a necrotic base and surrounding erythema. He reports a history of peripheral artery disease and intermittent claudication. Which of the following is the most likely underlying cause of this ulcer? A. Venous stasis ulcer B. Arterial insufficiency ulcer C. Diabetic foot ulcer D. Pressure ulcer Answer: B Explanation: The clinical presentation described is consistent with an arterial insufficiency ulcer. Arterial insufficiency ulcers typically occur in patients with peripheral artery disease and are often located on the lower extremities, especially the lower leg and foot. These ulcers are irregularly shaped, have a necrotic base, and are associated with surrounding erythema. Patients may also report symptoms of peripheral artery disease, such as intermittent claudication. Venous stasis ulcers, on the other hand, are typically located around the medial or lateral malleolus and are associated with edema and hemosiderin deposition. Diabetic foot ulcers are common in patients with diabetes and are often located on pressure points of the foot. Pressure ulcers result from prolonged pressure on bony prominences and are commonly seen in immobile or bedridden patients. Question: 14 A 55-year-old woman presents with a gradually enlarging, painless, pinkish nodule on her nose. On examination, you observe a translucent, pearly papule with prominent telangiectasias. There is a central depression and rolled, raised borders. What is the most likely diagnosis? A. Basal cell carcinoma B. Squamous cell carcinoma C. Melanoma D. Seborrheic keratosis Answer: A Explanation: The clinical presentation described is highly suggestive of basal cell carcinoma (BCC), the most common type of skin cancer. BCC typically presents as a pearly papule or nodule with telangiectasias. It often has a central depression and rolled, raised borders. Squamous cell carcinoma (SCC) may present as a scaly, erythematous plaque or a rapidly growing, tender nodule. Melanoma is characterized by an asymmetric mole with irregular borders, color variation, and a diameter larger than 6 mm. Seborrheic keratosis are benign lesions that present as sharply demarcated, waxy, stuck-on plaques with a "stuck-on" appearance. Question: 15 A 28-year-old female presents with a facial rash consisting of papules, pustules, and comedones. She reports a worsening of symptoms in response to sunlight exposure. On examination, you note erythematous papules and pustules on her cheeks and nose, with some areas of comedonal acne. She does not have a history of flushing or telangiectasias. Which of the following is the most likely diagnosis? A. Acne vulgaris B. Acne rosacea C. Seborrheic dermatitis D. Perioral dermatitis Answer: B Explanation: The presentation described is consistent with acne rosacea. Acne rosacea is a chronic inflammatory skin condition that primarily affects the central face, including the cheeks, nose, chin, and forehead. It is characterized by erythematous papules, pustules,and sometimes comedones. Unlike acne vulgaris, acne rosacea is typically not associated with significant involvement of the trunk or back. One distinguishing feature is the worsening of symptoms in response to sunlight exposure. Flushing and telangiectasias may also be present in rosacea, but they are not mentioned in the question stem. Acne vulgaris, on the other hand, typically presents with comedones, papules, and pustules on the face, chest, and back. Seborrheic dermatitis commonly affects oily areas of the skin, such as the scalp, face, and central chest, and is characterized by erythematous plaques with greasy scales. Perioral dermatitis presents as erythematous papules and pustules around the mouth, sparing the vermillion border. Question: 16 A 55-year-old male presents with a new growth on his nose. On examination, you observe a pearly, translucent papule with telangiectasias and a rolled, elevated border. There is no pain or bleeding associated with the lesion. Which of the following is the most likely diagnosis? A. Basal cell carcinoma B. Squamous cell carcinoma C. Malignant melanoma D. Actinic keratosis Answer: A Explanation: The clinical presentation described is consistent with basal cell carcinoma (BCC). BCC is the most common type of skin cancer and often occurs in sun-exposed areas, such as the face. It typically presents as a pearly, translucent papule with telangiectasias (tiny blood vessels) and a rolled, elevated border. BCC is usually painless and does not bleed easily. Squamous cell carcinoma may also occur on the nose but is more commonly associated with a crusted, scaly plaque or nodule. Malignant melanoma often presents as an asymmetric, pigmented lesion with irregular borders. Actinic keratosis is a precancerous lesion that appears as a rough, scaly patch and is not typically pearly or translucent.