Question: 1 A 28-year-old woman presents with a pruritic, erythematous rash with vesicles and weeping on her hands. She works as a hairdresser and frequently comes into contact with chemicals and water. What is the most likely diagnosis? A. Irritant contact dermatitis B. Allergic contact dermatitis C. Atopic dermatitis D. Dyshidrotic eczema Answer: D Explanation: The presentation of a pruritic, erythematous rash with vesicles and weeping on the hands, particularly in a patient with occupational exposure to chemicals and water (such as a hairdresser), is consistent with dyshidrotic eczema. Dyshidrotic eczema is a type of eczema characterized by small, deep-seated vesicles on the palms, soles, and lateral aspects of the fingers and toes. Irritant contact dermatitis is an inflammatory reaction to an irritant, while allergic contact dermatitis is an immune-mediated reaction to an allergen. Atopic dermatitis typically presents with intense pruritus, erythematous and excoriated patches, and a history of allergic conditions. Question: 2 A 40-year-old man presents with a pruritic, erythematous rash on his back, abdomen, and extremities. The rash consists of discrete, coin-shaped plaques with a silvery scale. On examination, Auspitz sign (pinpoint bleeding after scale removal) is observed. What is the most likely diagnosis? A. Psoriasis B. Pityriasis rosea C. Tinea corporis D. Nummular eczema Answer: A Explanation: The presentation of pruritic, erythematous coin-shaped plaques with a silvery scale, along with Auspitz sign, is highly suggestive of psoriasis. Psoriasis is a chronic autoimmune condition characterized by rapid skin cell turnover, resulting in the formation of thick, scaly plaques. Pityriasis rosea typically presents with a herald patch (large, salmon-colored patch) followed by smaller, oval-shaped, scaly lesions in a Christmas tree pattern. Tinea corporis, or ringworm, presents with annular, erythematous patches with central clearing and a raised, scaly border. Nummular eczema presents with coin-shaped plaques that are often pruritic and can be associated with a history of atopy. Question: 3 A 35-year-old man presents with a pruritic, raised, erythematous rash on his hands and fingers. The rash is vesicular and is accompanied by burning and tenderness. What is the most likely diagnosis? A. Atopic dermatitis B. Herpes simplex virus infection C. Scabies infestation D. Contact dermatitis Answer: B Explanation: The presentation of a pruritic, raised, erythematous rash on the hands and fingers, accompanied by vesicles, burning, and tenderness, is suggestive of herpes simplex virus (HSV) infection. HSV infection commonly presents as grouped vesicles on an erythematous base. Atopic dermatitis typically presents with intense pruritus, erythematous and excoriated patches. Scabies infestation is characterized by intense itching, especially at night, and the presence of burrows and papules. Contact dermatitis is an inflammatory reaction to an allergen or irritant, resulting in localized rash. Question: 4 A 50-year-old woman presents with a slowly enlarging, painless, red nodule on her nose. She reports occasional bleeding from the lesion. On examination, telangiectasias are noted on the surface of the nodule. What is the most likely diagnosis? A. Basal cell carcinoma B. Squamous cell carcinoma C. Melanoma D. Kaposi sarcoma Answer: A Explanation: The clinical presentation of a slowly enlarging, painless, red nodule with telangiectasias, particularly on sun-exposed areas such as the nose, is highly suggestive of basal cell carcinoma. Basal cell carcinoma is the most common type of skin cancer and typically presents as a non-healing, pearly or translucent nodule with telangiectasias. Squamous cell carcinoma often presents as a firm, pink, scaly plaque or nodule. Melanoma commonly presents as an asymmetrical pigmented lesion with irregular borders. Kaposi sarcoma is characterized by red, violaceous nodules or plaques, often involving the skin, oral mucosa, and internal organs. Question: 5 A 45-year-old woman presents with a pruritic, erythematous rash with silvery scales on her elbows, knees, and scalp. The rash is symmetrically distributed and has been present for several months. What is the most likely diagnosis? A. Psoriasis B. Atopic dermatitis C. Contact dermatitis D. Seborrheic dermatitis Answer: A Explanation: The presentation of symmetrically distributed, pruritic, erythematous rash with silvery scales on the elbows, knees, and scalp is consistent with psoriasis. Psoriasis is a chronic autoimmune condition characterized by rapid skin cell turnover, resulting in the formation of thick, scaly plaques. Atopic dermatitis typically presents with intense pruritus, erythematous and excoriated patches, and a history of allergic conditions. Contact dermatitis is an inflammatory reaction to an allergen or irritant, resulting in localized rash. Seborrheic dermatitis is characterized by greasy, erythematous patches with yellowish scales, commonly affecting the scalp, face, and chest. Question: 6 A 30-year-old woman presents with a pruritic, erythematous rash on her face, particularly involving the cheeks and nose. The rash worsens with sun exposure. On examination, telangiectasias and papules are noted on the affected areas. What is the most likely diagnosis? A. Systemic lupus erythematosus (SLE) B. Rosacea C. Acne vulgaris D. Contact dermatitis Answer: B Explanation: The presentation of a pruritic, erythematous rash on the face, particularly involving the cheeks and nose, worsened by sun exposure and accompanied by telangiectasias and papules, is consistent with rosacea. Rosacea is a chronic inflammatory condition that primarily affects the face and is characterized by flushing, persistent erythema, telangiectasias, and inflammatory papules and pustules. Systemic lupus erythematosus (SLE) can present with a malar rash, but it is typically more diffuse and associated with other systemic symptoms. Acne vulgaris commonly presents with comedones, papules, pustules, and nodules. Contact dermatitis is an inflammatory reaction to an allergen or irritant, resulting in localized rash. Question: 7 A 22-year-old man presents with a solitary indurated penile ulcer with relatively clean margins, no obvious raised granulomatous areas, and no discoloration. It began as a hard, nonpainful nodule. Regional lymphadenopathy is present. What is the most likely etiologic agent? A. Haemophilus ducreyi B. Human papillomavirus, serotype 11 C. Streptococcus pyogenes D. Treponema pallidum Answer: D Explanation: The presentation of a solitary indurated penile ulcer with clean margins, no raised granulomatous areas, and regional lymphadenopathy is highly suggestive of syphilis. The most common etiologic agent responsible for syphilis is Treponema pallidum. Haemophilus ducreyi is the causative agent of chancroid, which presents with painful genital ulcers and tender inguinal lymphadenopathy. Human papillomavirus (HPV) infection typically leads to genital warts, while Streptococcus pyogenes is associated with streptococcal infections, such as cellulitis and impetigo. Question: 8 A 55-year-old man presents with a red, scaly rash on his lower legs. The rash is associated with mild pain and swelling. On examination, there are shallow, punched-out ulcers with necrotic bases. The patient has a history of diabetes mellitus. What is the most likely diagnosis? A. Stasis dermatitis B. Pyoderma gangrenosum C. Diabetic foot ulcer D. Venous stasis ulcer Answer: D Explanation: The presentation of a red, scaly rash on the lower legs associated with shallow, punched-out ulcers with necrotic bases in a patient with a history of diabetes mellitus is highly suggestive of venous stasis ulcers. Venous stasis ulcers are commonly seen in patients with chronic venous insufficiency and occur due to impaired venous return, resulting in edema, inflammation, and ultimately, ulceration. Stasis dermatitis is characterized by erythematous, pruritic, and scaly patches or plaques. Pyoderma gangrenosum is a rare, inflammatory condition characterized by rapidly progressing, painful ulcers with undermined violaceous borders. Diabetic foot ulcers typically occur in patients with diabetes and are often associated with peripheral neuropathy and peripheral vascular disease.