Free dermatology MCQ exam model for clinical students

Explanation:

• Hormonal influence and follicular blockage → Correct because increased sebum and follicular plugging lead to acne.

• Bacterial infection alone → Incorrect because bacteria are secondary.

• Allergic reaction → Incorrect because acne is not allergic.

• Poor hygiene → Incorrect because acne is not due to dirt.

• Autoimmune process → Incorrect because acne is not autoimmune.

Explanation:

• Basal cell carcinoma → Correct because it is the most common skin cancer.

• Melanoma → Incorrect because it is less common but more aggressive.

• Squamous cell carcinoma → Incorrect because it is second most common.

• Kaposi sarcoma → Incorrect because it is HIV-related.

• Merkel cell carcinoma → Incorrect because it is rare.

Explanation:

• Vitiligo → Correct because autoimmune destruction of melanocytes occurs.

• Melasma → Incorrect because it is increased melanin production.

• Albinism → Incorrect because melanocytes are present but melanin synthesis is reduced.

• Tinea versicolor → Incorrect because it is fungal infection.

• Addison disease → Incorrect because it causes hyperpigmentation.

Explanation:

• Permethrin → Correct because topical permethrin is first-line treatment.

• Fluconazole → Incorrect because it is antifungal.

• Ivermectin → Incorrect because it is alternative oral therapy.

• Acyclovir → Incorrect because it treats viral infections.

• Metronidazole → Incorrect because it treats anaerobic infections.

Explanation:

• Purple, polygonal, pruritic papules → Correct because they define lichen planus.

• Silvery scales → Incorrect because they are seen in psoriasis.

• Target lesion → Incorrect because it is seen in erythema multiforme.

• Vesicular eruption → Incorrect because it suggests herpes.

• Hypopigmented macules → Incorrect because they are seen in vitiligo.

Explanation:

• Tinea pedis → Correct because athlete’s foot is the most common dermatophytosis.

• Candidiasis → Incorrect because it affects mucosa.

• Tinea corporis → Incorrect because it affects body skin.

• Pityriasis versicolor → Incorrect because it affects trunk.

• Onychomycosis → Incorrect because it affects nails.

Explanation:

• Pemphigus vulgaris → Correct because intraepidermal acantholysis causes skin sloughing.

• Bullous pemphigoid → Incorrect because Nikolsky sign is negative.

• Dermatitis herpetiformis → Incorrect because it is IgA-mediated.

• Epidermolysis bullosa → Incorrect because it is genetic.

• Impetigo → Incorrect because it is bacterial.

Explanation:

• Plaque → Correct because well-demarcated erythematous plaques with silvery scales are typical.

• Vesicle → Incorrect because it is fluid-filled.

• Bulla → Incorrect because it is a large blister.

• Pustule → Incorrect because it contains pus.

• Nodule → Incorrect because it is deeper lesion.

Explanation:

• Psoriasis → Correct because removal of scales causes pinpoint bleeding.

• Eczema → Incorrect because it causes oozing.

• Lichen planus → Incorrect because it shows Wickham striae.

• Vitiligo → Incorrect because it causes depigmentation.

• Pemphigus vulgaris → Incorrect because it shows Nikolsky sign.

Explanation:

• Skin, hair, and nails → Correct because dermatology focuses on cutaneous structures and appendages.

• Heart → Incorrect because this is cardiology.

• Lungs → Incorrect because this is pulmonology.

• Nervous system → Incorrect because this is neurology.

• Endocrine glands → Incorrect because this is endocrinology.