ABD MCQ 1 — Questions and Answers

Question 1: Which layer of the skin contains blood vessels and nerves?

Epidermis
Dermis (Correct answer)
Stratum corneum
Subcutaneous layer

Correct answer: Dermis

The dermis is the layer of skin located beneath the epidermis. It is rich in connective tissue, blood vessels that supply nutrients and regulate temperature, and nerves that detect sensations like touch, pain, and temperature. The epidermis, in contrast, is avascular (lacks blood vessels) and primarily provides protection.

Question 2: Which condition is commonly treated with topical corticosteroids?

Acne vulgaris
Psoriasis
Eczema (Correct answer)
Warts

Correct answer: Eczema

Eczema (atopic dermatitis) is characterized by inflammation, itching, and redness of the skin. Topical corticosteroids are a primary treatment for eczema because they effectively reduce inflammation and suppress the immune response in the affected skin, alleviating symptoms. While they might be used for other conditions, they are a cornerstone for eczema management.

Question 3: What is the typical presentation of basal cell carcinoma?

Dark flat mole with irregular borders
Red patch with scaling
Pearly nodule with telangiectasia (Correct answer)
Thickened skin with white patches

Correct answer: Pearly nodule with telangiectasia

Basal cell carcinoma (BCC) typically presents as a pearly or translucent nodule, often with rolled borders and visible small blood vessels (telangiectasia) on its surface. It can also appear as a flat, firm, pale area or a red patch. This classic description helps differentiate it from other skin lesions and aids in early diagnosis.

Question 4: Which microorganism is most commonly responsible for acne?

Staphylococcus aureus
Escherichia coli
Cutibacterium acnes (Correct answer)
Candida albicans

Correct answer: Cutibacterium acnes

Cutibacterium acnes (formerly Propionibacterium acnes) is a bacterium that lives on the skin and is a primary contributor to the development of acne vulgaris. It thrives in the anaerobic environment of clogged hair follicles, breaking down sebum and producing inflammatory byproducts that lead to the characteristic lesions of acne.

Question 5: What is a hallmark sign of psoriasis?

Blistering rash
Target lesions
Thick, scaly, red plaques (Correct answer)
Widespread pigmentation loss

Correct answer: Thick, scaly, red plaques

Psoriasis is a chronic autoimmune skin condition characterized by the rapid overproduction of skin cells, leading to the formation of distinctive thick, silvery-white scales on red, inflamed patches called plaques. These plaques are typically well-demarcated and can appear anywhere on the body, commonly on elbows, knees, and scalp.

Question 6: Which vitamin is synthesized in the skin upon exposure to sunlight?

Vitamin A
Vitamin B12
Vitamin C
Vitamin D (Correct answer)

Correct answer: Vitamin D

The skin plays a crucial role in vitamin D synthesis. When exposed to ultraviolet B (UVB) radiation from sunlight, a precursor molecule in the skin (7-dehydrocholesterol) is converted into pre-vitamin D3, which then isomerizes to vitamin D3. This process is essential for calcium absorption and bone health.

Question 7: Which test is most appropriate for diagnosing fungal skin infections?

Patch testing
KOH prep (Correct answer)
Biopsy with immunohistochemistry
Bacterial culture

Correct answer: KOH prep

The KOH (potassium hydroxide) prep is the most appropriate initial test for diagnosing fungal skin infections. It involves scraping skin cells and dissolving keratinocytes with KOH, which allows for direct microscopic visualization of fungal elements like hyphae and spores. This method is rapid, inexpensive, and highly effective in confirming the presence of a fungal infection, guiding prompt and accurate treatment.

Question 8: Which lesion is considered pre-malignant?

Seborrheic keratosis
Actinic keratosis (Correct answer)
Cherry angioma
Skin tag

Correct answer: Actinic keratosis

Actinic keratosis (AK) is considered a pre-malignant lesion, meaning it has the potential to develop into skin cancer. These rough, scaly patches typically appear on sun-exposed areas and are caused by chronic ultraviolet radiation damage. If left untreated, AKs can progress to invasive squamous cell carcinoma, making early detection and treatment crucial for prevention.

Question 9: What is the best initial treatment for mild comedonal acne?

Oral antibiotics
Topical retinoids (Correct answer)
Systemic steroids
Laser therapy

Correct answer: Topical retinoids

For mild comedonal acne, topical retinoids are the best initial treatment. These medications work by normalizing follicular keratinization, which helps to prevent the formation of new comedones (blackheads and whiteheads) and promote the shedding of existing ones. This mechanism directly addresses the primary pathology of comedonal acne, making them highly effective as a first-line therapy.

ABD MCQ 1

Which layer of the skin contains blood vessels and nerves?