Androgenetic Alopecia — MCQs
What is the primary mechanism of action of 5-α reductase?
Which of the following are treatment options for acne vulgaris?
Which antihypertensive agent is used topically to treat alopecia and should be used with caution in young females?
A male presents with alopecia and exclamation mark hairs. Diagnosis?
Rapid, diffuse, excessive hair loss occurring 3 months after childbirth is due to?
Swarm of bees appearance seen in?
A male presents with alopecia and exclamation mark hairs. Diagnosis?
Non-scarring alopecia is associated with all except?
Consider the following causes of alopecia: 1. Androgenetic alopecia 2. Alopecia areata 3. Telogen effluvium 4. Lichen planopilaris. Which among the following causes non-scarring alopecia?
Pitting of nails is seen in:
Androgenetic Alopecia Indian Medical PG Practice Questions and MCQs
Question 1: What is the primary mechanism of action of 5-α reductase?
- A. Reduction of C4-C5 double bond (Correct Answer)
- B. Breakage of amide bond
- C. Breakage of C-N bond
- D. Breakage of N-N bond
Explanation: ***Reduction of C4-C5 double bond*** - 5-α reductase is a **NADPH-dependent reductase enzyme** that catalyzes the **reduction (saturation) of the C4-C5 double bond** in the A-ring of testosterone to form **dihydrotestosterone (DHT)**. - This reduction involves **adding two hydrogen atoms** across the double bond, converting it to a single bond with **5-α stereochemistry**. - DHT is a more potent androgen crucial for **prostate development, external genitalia formation, and male pattern baldness**, making 5-α reductase inhibitors (like finasteride) clinically important for treating benign prostatic hyperplasia and androgenetic alopecia. *Breakage of amide bond* - Breaking **amide bonds (C-N bonds with a carbonyl)** is the function of **proteases and amidases**, not reductases. - This process involves **hydrolysis** and is fundamental to protein degradation and peptide metabolism. *Breakage of C-N bond* - **Carbon-nitrogen bond cleavage** occurs in reactions like **deamination** (catalyzed by deaminases) or metabolism of nitrogenous compounds. - Reductases perform **electron transfer reactions**, not bond cleavage reactions. *Breakage of N-N bond* - **Nitrogen-nitrogen bond** cleavage is rare in human biochemistry and may occur in hydrazine metabolism or by specialized enzymes. - Steroid hormones do not contain N-N bonds, making this mechanism irrelevant to 5-α reductase function.
Question 2: Which of the following are treatment options for acne vulgaris?
- A. Isotretinoin
- B. All of the options (Correct Answer)
- C. Topical erythromycin
- D. Oral Minocycline
Explanation: ***All of the options*** - All listed options (Isotretinoin, Topical erythromycin, and Oral Minocycline) are well-established and commonly used **treatment options for acne vulgaris**, depending on the severity and type of acne. - The choice of treatment often follows a stepped approach, starting with topical agents for mild to moderate acne and progressing to oral medications like antibiotics or isotretinoin for more severe or resistant cases. *Isotretinoin* - **Isotretinoin** is a powerful oral retinoid primarily used for **severe, recalcitrant nodular acne** that has not responded to other treatments. - It works by reducing sebum production, follicular hyperkeratinization, inflammation, and the growth of *P. acnes*. *Topical erythromycin* - **Topical erythromycin** is an **antibiotic** used to treat mild to moderate inflammatory acne by reducing the growth of *Cutibacterium acnes* (formerly *Propionibacterium acnes*) and decreasing inflammation. - It is often combined with other topical agents like benzoyl peroxide to minimize the development of **antibiotic resistance**. *Oral Minocycline* - **Oral minocycline** is a **tetracycline antibiotic** used for moderate to severe inflammatory acne. - It reduces bacterial populations on the skin and exhibits **anti-inflammatory properties**, making it effective for widespread or deeper lesions.
Question 3: Which antihypertensive agent is used topically to treat alopecia and should be used with caution in young females?
- A. Hydralazine
- B. Prazosin
- C. Minoxidil (Correct Answer)
- D. Indapamide
Explanation: ***Minoxidil*** - **Minoxidil** is a direct **vasodilator** that, when applied topically, stimulates hair growth and is commonly used for **androgenetic alopecia**. - It should be used with caution in young females due to the potential for **hypertrichosis** (unwanted hair growth) outside the scalp if not applied precisely. *Hydralazine* - **Hydralazine** is a direct-acting **vasodilator** primarily used orally or intravenously to treat moderate to severe hypertension and heart failure. - It is not used topically for alopecia and acts differently on blood vessels than minoxidil. *Prazosin* - **Prazosin** is an **alpha-1 adrenergic blocker** used orally to treat hypertension, benign prostatic hyperplasia, and sometimes PTSD. - It is not indicated for topical use in alopecia. *Indapamide* - **Indapamide** is a **thiazide-like diuretic** that acts by increasing the excretion of sodium and water, primarily used to treat hypertension and edema. - It has no known role in the topical treatment of alopecia.
Question 4: A male presents with alopecia and exclamation mark hairs. Diagnosis?
- A. Telogen effluvium
- B. Androgenic alopecia
- C. Alopecia areata (Correct Answer)
- D. Tinea capitis
Explanation: ***Alopecia areata*** - The presence of **exclamation mark hairs** (hairs that are narrower closer to the scalp and wider at the distal end) is a classic dermatoscopic finding specifically associated with **alopecia areata**. - **Alopecia areata** is an autoimmune condition characterized by patchy hair loss and often presents with these peculiar hair shaft abnormalities. *Telogen effluvium* - This condition involves diffuse thinning of hair, often triggered by stress, illness, or hormonal changes, but does not typically present with **exclamation mark hairs**. - It is characterized by an increased shedding of **telogen (resting phase)** hairs, with no specific hair shaft abnormalities like exclamation marks. *Androgenic alopecia* - This is the most common type of hair loss, characterized by a patterned balding (receding hairline, thinning crown), due to the effect of androgens on genetically susceptible hair follicles. - While it causes hair miniaturization, it does not involve the formation of **exclamation mark hairs**. *Tinea capitis* - This is a **fungal infection** of the scalp that typically causes scaly patches, broken hairs, and sometimes inflammation or painful lesions, often with associated **lymphadenopathy**. - The distinctive **exclamation mark hairs** are not a feature of **tinea capitis**; instead, broken-off hairs or "black dots" may be observed.
Question 5: Rapid, diffuse, excessive hair loss occurring 3 months after childbirth is due to?
- A. Telogen effluvium (Correct Answer)
- B. Anagen effluvium
- C. Alopecia areata
- D. Androgenetic alopecia
Explanation: ***Telogen effluvium*** - This condition is characterized by an excessive shedding of **club hairs** from the hair follicle, typically occurring 2-4 months after a significant stressor such as **pregnancy and childbirth**. - During pregnancy, high estrogen levels increase the number of follicles in the anagen (growth) phase; after delivery, estrogen drops, and many follicles simultaneously enter the **telogen (resting) phase**, leading to synchronized shedding. *Anagen effluvium* - This type of hair loss is rapid and severe, occurring when a significant percentage of **hair follicles** in the **anagen phase** are abruptly stopped from growing. - It is often seen with **chemotherapy, radiation therapy**, or exposure to toxins, which damage actively dividing hair matrix cells. *Alopecia areata* - This is an **autoimmune condition** where the body's immune system attacks hair follicles, leading to distinct, typically **round patches of hair loss**. - It can affect any hair-bearing area and is not directly linked to hormonal changes post-pregnancy. *Androgenetic alopecia* - Commonly known as **male or female pattern baldness**, this is a genetic condition influenced by androgens, characterized by a progressive **miniaturization of hair follicles**. - It presents as a characteristic pattern of thinning, such as a receding hairline or thinning at the crown, and is not typically a rapid, diffuse postpartum event.
Question 6: Swarm of bees appearance seen in?
- A. Telogen effluvium
- B. Alopecia areata (Correct Answer)
- C. Androgenetic alopecia
- D. Anagen effluvium
Explanation: ***Alopecia areata*** - The "swarm of bees" appearance refers to the characteristic **peribulbar lymphocytic inflammation** seen on scalp biopsy in active alopecia areata. - This finding represents an **immune response targeting the hair follicles**, leading to non-scarring hair loss. *Telogen effluvium* - Histologically, telogen effluvium is characterized by a high proportion of **telogen hairs** in the hair counts and **no significant inflammation** around the follicles. - The "swarm of bees" peribulbar infiltrate is not a feature of telogen effluvium, which is typically a reaction to a systemic stressor. *Androgenetic alopecia* - Androgenetic alopecia is characterized by **follicular miniaturization**, where vellus hairs replace terminal hairs, and a **decrease in the number of hair follicles**. - It does not show the "swarm of bees" peribulbar lymphocytic infiltrate; instead, there might be subtle inflammation or fibrosis in advanced stages but not the dense peribulbar type. *Anagen effluvium* - Anagen effluvium is characterized by the **sudden shedding of hairs in the anagen phase** due to a toxic or inflammatory insult disrupting hair matrix keratinocyte proliferation. - Histology often shows **dystrophic anagen hairs** and damaged hair shafts, but not the specific "swarm of bees" lymphocytic infiltrate seen in alopecia areata.
Question 7: A male presents with alopecia and exclamation mark hairs. Diagnosis?
- A. Alopecia areata (Correct Answer)
- B. Tinea capitis
- C. Telogen effluvium
- D. Androgenic alopecia
Explanation: ***Alopecia areata*** - **Alopecia areata** is characterized by sudden, non-scarring hair loss that can affect any hair-bearing area, including the scalp. - The presence of **exclamation mark hairs** (hairs that are narrower closer to the scalp) is a classic dermatoscopic finding in alopecia areata and is highly suggestive of the diagnosis. *Tinea capitis* - **Tinea capitis** is a fungal infection of the scalp often presenting with scaling, erythema, and broken hairs, but typically not "exclamation mark hairs." - It may cause **patchy alopecia** but is usually associated with inflammation and sometimes pustules. *Telogen effluvium* - **Telogen effluvium** is a diffuse, non-scarring hair shedding that occurs after a stressful event, leading to widespread thinning rather than localized patches. - It primarily involves an increase in the number of hairs in the **telogen (resting) phase** and does not typically feature exclamation mark hairs. *Androgenic alopecia* - **Androgenic alopecia**, or male/female pattern baldness, is characterized by a gradual, patterned hair loss due to genetic and hormonal factors. - It involves the miniaturization of hair follicles and progressive thinning, but it does not present with **exclamation mark hairs** or discrete patches of complete hair loss.
Question 8: Non-scarring alopecia is associated with all except?
- A. Telogen effluvium
- B. Androgenetic alopecia
- C. Alopecia areata
- D. Frontal fibrosing alopecia (Correct Answer)
Explanation: ***Frontal fibrosing alopecia*** - This condition is a form of **lichen planopilaris**, which causes **scarring alopecia** due to destruction of hair follicles and replacement with fibrous tissue. - It results in a **receding hairline** and eyebrow loss, with irreversible hair loss. *Telogen effluvium* - This is a common cause of **non-scarring alopecia**, characterized by diffuse hair shedding triggered by various stressors like illness, stress, or medications. - The hair follicles enter the **telogen phase** prematurely, leading to increased shedding but typically regrowth once the trigger is removed. *Androgenetic alopecia* - Often referred to as **male or female pattern baldness**, this is a form of **non-scarring alopecia** driven by genetic predisposition and androgens. - It causes a progressive miniaturization of hair follicles, leading to thinning hair, but the follicles remain present and capable of producing hair. *Alopecia areata* - This is an **autoimmune condition** that causes **non-scarring hair loss** in patches on the scalp or other parts of the body. - The hair follicles are attacked by the immune system but are not permanently destroyed, allowing for potential regrowth.
Question 9: Consider the following causes of alopecia: 1. Androgenetic alopecia 2. Alopecia areata 3. Telogen effluvium 4. Lichen planopilaris. Which among the following causes non-scarring alopecia?
- A. 1, 2 and 3 (Correct Answer)
- B. Only 4
- C. 3 and 4
- D. 2, 3 and 4
Explanation: **1, 2, and 3** - **Androgenetic alopecia**, **alopecia areata**, and **telogen effluvium** are all forms of **non-scarring alopecia**, meaning the hair follicles are primarily affected without permanent destruction. - In these conditions, there is potential for hair regrowth as the follicular structures remain intact. *Only 4* - **Lichen planopilaris** is a type of **scarring alopecia**, characterized by permanent destruction of hair follicles and replacement with fibrous tissue. - This leads to irreversible hair loss in the affected areas. *3 and 4* - While **telogen effluvium** causes non-scarring alopecia, **lichen planopilaris** is a scarring alopecia. - Therefore, this option incorrectly groups a non-scarring and a scarring condition. *2, 3, and 4* - This option correctly identifies **alopecia areata** and **telogen effluvium** as non-scarring but incorrectly includes **lichen planopilaris**, which results in scarring alopecia. - **Lichen planopilaris** has inflammatory infiltrates that lead to permanent follicular damage.
Question 10: Pitting of nails is seen in:
- A. Psoriasis and Alopecia areata (Correct Answer)
- B. Psoriasis only
- C. Psoriasis and Lichen planus
- D. Alopecia areata and Eczema
Explanation: ***Psoriasis and Alopecia areata*** - **Nail pitting** is a very common and characteristic finding in **psoriasis**, resulting from defective keratinization of the nail matrix. - While less common, nail pitting can also occur in **alopecia areata**, typically due to inflammation affecting the nail matrix. *Psoriasis only* - While **psoriasis** is a primary cause of nail pitting, stating it as "only" is incorrect as other conditions also present with this sign. - This option incorrectly limits the differential diagnosis for nail pitting. *Psoriasis and Lichen planus* - **Psoriasis** does cause nail pitting, but **lichen planus** typically causes **longitudinal ridging**, splitting, subungual hyperkeratosis, and sometimes pterygium formation, rather than classic pitting. - This option includes a condition that usually manifests with different nail changes. *Alopecia areata and Eczema* - **Alopecia areata** can cause nail pitting, but **eczema** of the hands or fingers more commonly leads to **nail plate dystrophy**, discoloration, ridging, or thickening, rather than distinct pitting. - While eczema can affect nails, pitting is not its characteristic nail manifestation.
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