Basic Dermatology Practice Questions

Q: Phrynoderma is primarily associated with a deficiency of which of the following?

Vitamin A. ***Vitamin A*** - **Phrynoderma** (toad skin) has been **classically attributed to vitamin A deficiency** in traditional medical literature and was the accepted answer in historical examinations. - It presents as **follicular hyperkeratosis** with dry, scaly, rough skin having prominent hair follicles with a sandpaper-like texture. - However, **modern evidence** suggests phrynoderma is a **multifactorial condition** often involving **multiple nutritional deficiencies**, with vitamin A being one important contributor among others. *Essential fatty acid* - Deficiency of **essential fatty acids** (linoleic and alpha-linolenic acid) causes **skin dryness, flakiness, and follicular hyperkeratosis**. - **Recent studies** indicate EFA deficiency may play a **significant role** in phrynoderma, particularly in developing countries where multiple nutritional deficiencies coexist. - The clinical presentation can closely mimic vitamin A deficiency-related skin changes. *Vitamin D* - Deficiency of **vitamin D** primarily causes **rickets** in children and **osteomalacia** in adults with bone pain, muscle weakness, and skeletal deformities. - While vitamin D has roles in skin health, its deficiency does not directly cause the follicular hyperkeratosis characteristic of phrynoderma. *Niacin* - **Niacin (vitamin B3)** deficiency causes **pellagra** with the classic \"3 Ds\": **dermatitis, diarrhea, and dementia**. - Pellagra dermatitis is typically **symmetrical in sun-exposed areas** with redness, scaling, and hyperpigmentation—distinctly different from the follicular pattern of phrynoderma.

Q: Itchy purple papule followed by hyperpigmentation on resolution, is seen in?

Lichen planus. ***Correct: Lichen planus*** - This condition presents with characteristic **pruritic (itchy) violaceous (purple) papules** that often develop **post-inflammatory hyperpigmentation** upon resolution. - The classic presentation follows the **"5 P's": Purple, Pruritic, Polygonal, Planar, Papules**. - Lesions commonly affect the **wrists, ankles, lower back, and genitals**, and may also involve the **oral mucosa** (Wickham's striae). - The hyperpigmentation on resolution is due to **melanin incontinence** and dermal melanophages. *Incorrect: Addison's disease* - Characterized by **hyperpigmentation**, but this is typically diffuse, affecting sun-exposed areas, pressure points, and mucous membranes (e.g., gum line), not discrete papules. - The pigmentation is due to increased **ACTH stimulating melanocytes**, without an initial itchy papular stage. *Incorrect: DM (Diabetes Mellitus)* - Diabetes Mellitus can cause various skin manifestations, including **acanthosis nigricans**, necrobiosis lipoidica diabeticorum, and diabetic dermopathy. - These manifestations do not typically present as itchy purple papules followed by hyperpigmentation, but rather as thickened, velvety skin folds or atrophic, pigmented lesions. *Incorrect: Hypothyroidism* - Can lead to **dry, coarse skin**, and occasionally **non-pitting edema** (myxedema). - It does not present with itchy purple papules or lesions that resolve with hyperpigmentation.

Q: Loss of intercellular cohesion between keratinocytes is referred to as?

Acantholysis. ***Acantholysis*** - This term specifically refers to the **loss of cohesion between keratinocytes** in the epidermis due to the breakdown of desmosomal attachments. - It is a hallmark feature of several **blistering skin diseases**, such as pemphigus. *Acanthosis* - This refers to the **thickening of the stratum spinosum** (prickle cell layer) of the epidermis, often due to an increase in the number of keratinocytes. - It is seen in conditions like **psoriasis** and seborrheic keratosis, but does not involve a loss of intercellular cohesion. *Keratinolysis* - This term describes the **breakdown or dissolution of keratin**, which is the primary structural protein of the epidermis. - While keratinocytes produce keratin, keratinolysis itself is not the specific term for loss of cohesion between these cells. *Spongiosis* - This is defined as **intercellular edema** (fluid accumulation) within the epidermis, especially prominent in the stratum spinosum. - It leads to the widening of intercellular spaces and stretching of desmosomes, but the cells generally remain attached, unlike in acantholysis.

Q: Which of the following statements about spider telangiectasia is false?

More common in males. ***More common in males*** - This statement is **FALSE** because spider telangiectasias (spider nevi/spider angiomas) are more commonly observed in **females**, often due to hormonal influences like **estrogen**. - They are frequently associated with conditions such as **pregnancy**, **oral contraceptive use**, or **chronic liver disease**, highlighting a female predominance. - The estrogen-dependent nature explains their higher prevalence in women of reproductive age. *Can be caused by trauma* - This statement is **TRUE** in a broader sense, though classical spider telangiectasias are primarily hormonally-mediated rather than traumatic. - While **simple telangiectasias** can develop after localized trauma or repeated pressure, spider telangiectasias have a characteristic morphology (central arteriole with radiating vessels) and are typically associated with **estrogen excess** or **liver disease**. - For exam purposes, this is considered a true statement as telangiectatic vessels can be influenced by local factors. *Light therapy for treatment* - This statement is **TRUE**. **Laser therapy**, specifically **pulsed dye laser (PDL)** or **intense pulsed light (IPL)**, is the most effective treatment for spider telangiectasias. - The laser selectively targets **hemoglobin** in the dilated vessels, causing photocoagulation and vessel obliteration, leading to excellent cosmetic results. *May be associated with liver disease* - This statement is **TRUE**. Spider telangiectasias are a well-recognized cutaneous manifestation of **chronic liver disease**, especially **cirrhosis**. - Impaired hepatic function leads to decreased **estrogen metabolism** (hyperestrogenemia), contributing to the development of these vascular lesions. - They are one of the stigmata of chronic liver disease, along with palmar erythema and gynecomastia.

Q: Erythematous cutaneous nodules may be caused by the following except:

Herpes Simplex Virus (HSV). ***Herpes Simplex Virus (HSV)*** - HSV typically causes **vesicles, blisters, and ulcers**, not erythematous cutaneous nodules. - While it can manifest with various skin findings, **nodules** are not a characteristic presentation. *Bartonella* - **Bacillary angiomatosis**, caused by *Bartonella* species, presents with **vascular proliferation** that can appear as erythematous papules or nodules. - It is frequently seen in **immunocompromised individuals**. *Acanthamoeba* - **Acanthamoeba** infections can lead to disseminated disease in immunocompromised patients, presenting with **cutaneous nodules, plaques, or ulcers**. - These skin lesions are a manifestation of **hematogenous spread**. *Kaposi's sarcoma* - Kaposi's sarcoma lesions are characteristically **violaceous or brownish-red papules, plaques, or nodules** that are often erythematous in early stages. - It is a **vascular neoplasm** strongly associated with **HHV-8 infection**, particularly in immunocompromised patients.

Q: 25-year-old male having fever and malaise for 2 weeks, arthritis of the ankle joint, and tender erythematous nodules over the shin. What is the diagnosis?

Erythema nodosum. ***Erythema nodosum*** - Erythema nodosum presents with **tender, erythematous nodules** on the shins, often associated with a **prodrome of fever and malaise**, and can be accompanied by **arthralgia or arthritis**, particularly in the ankle joint [1]. - It is a **panniculitis** (inflammation of subcutaneous fat) that can be triggered by various systemic conditions, infections, or drugs. *Hansen's disease* - Also known as **leprosy**, this infectious disease primarily affects the skin, peripheral nerves, upper respiratory tract, eyes, and testes, typically presenting with **hypopigmented skin lesions** with loss of sensation. - While it can cause skin nodules (lepromas) and nerve damage leading to joint deformities, the acute onset of tender erythematous shin nodules accompanying a generalized inflammatory response is **not characteristic** of its initial presentation. *Weber-Christian disease* - This is a rare, relapsing, febrile **panniculitis** that causes subcutaneous fat inflammation, often resulting in tender nodules or plaques, but it is not typically associated with prominent arthralgia/arthritis as primary symptoms. - The lesions tend to be more widespread than just the shins and can involve visceral fat, and it lacks the specific association with ankle arthritis seen in erythema nodosum. *Nodular Vasculitis* - This condition is a form of **cutaneous vasculitis** that presents with multiple, tender, often ulcerating nodules, typically on the lower legs, which are characterized by inflammation of blood vessels. - While it involves nodules, it is fundamentally a vasculitic process and usually presents with symptoms of **vascular damage** such as ulcers, purpura, or livedo reticularis, which are not described in the patient's presentation of fever, malaise, and arthritis.

Q: Target or iris lesions are seen in:

Erythema multiforme. ***Erythema multiforme*** - Erythema multiforme is characterized by **target lesions** (also known as iris lesions), which are concentric rings of color resembling a bull's-eye. - These lesions typically have a **dusky center**, a paler edematous ring, and an outer erythematous halo. *Urticaria (hives)* - Urticaria presents with **pruritic, transient wheals** (hives) that are typically erythematous and edematous, but they do not form target or iris patterns. - The lesions in urticaria are often **blanchable** and migrate rapidly. *Scabies (itch mite infestation)* - Scabies manifests as **intensely pruritic papules, vesicles, and burrows**, often found in web spaces of fingers, wrists, and genitalia. - It does not produce target lesions; burrows are a **pathognomonic sign**. *Lichen planus (inflammatory skin condition)* - Lichen planus characteristically presents with **pruritic, polygonal, purple, planar papules and plaques** (the 6 P's). - It may also show **Wickham's striae** (fine white lines on the surface), but it does not form target-like lesions.

Q: Which of the following statements about erythema multiforme is false?

Lesions are usually asymmetrical.. ***Lesions are usually asymmetrical.*** - Erythema multiforme characteristically presents with **bilateral and symmetrical lesions**, not asymmetrical ones. - The classic **targetoid lesions** (distinctive bullseye shape) typically appear symmetrically on the extremities and trunk. - This statement is FALSE and is therefore the correct answer to this question. *Due to Herpes simplex* - **Herpes simplex virus (HSV) infection** is the most common infectious cause of erythema multiforme, particularly the recurrent form. - The rash typically appears 1-3 weeks after an HSV outbreak. - This statement is TRUE. *Due to sulphonamide* - **Sulfonamide drugs** are well-known to trigger drug-induced erythema multiforme, as well as more severe forms like Stevens-Johnson syndrome (SJS). - This highlights its association with medications as triggers. - This statement is TRUE. *Mucous membrane involvement occurs in EM major* - **Mucous membrane involvement** is a defining feature of **erythema multiforme major**, affecting the oral cavity, eyes, and genitals. - **EM minor** typically presents with only cutaneous lesions without significant mucosal involvement. - This statement is TRUE.

Q: Which of the following conditions is associated with acanthosis nigricans?

Type 2 Diabetes Mellitus. Acanthosis nigricans is characterized by velvety, hyperpigmented skin lesions, often in intertriginous areas, and is a common cutaneous marker for insulin resistance, which is central to Type 2 Diabetes Mellitus [1]. The elevated insulin levels stimulate epidermal keratinocytes and dermal fibroblast proliferation, leading to the characteristic skin changes. While malignant acanthosis nigricans is associated with internal malignancies, particularly adenocarcinomas of the gastrointestinal tract (like gastric), it is a less common cause than insulin resistance. This form is usually more extensive and rapidly progressing than the benign variant. Obesity is strongly associated with insulin resistance, making it an indirect cause of acanthosis nigricans. However, acanthosis nigricans is a direct indicator of insulin resistance, which can occur with or without significant obesity. While all listed conditions can be associated with acanthosis nigricans, Type 2 Diabetes Mellitus is the most direct and common condition explicitly linked to the underlying pathophysiology of insulin resistance [1]. Gastric adenocarcinoma causes a malignant form, and obesity is a risk factor for insulin resistance, but T2DM directly reflects the metabolic state responsible for the skin changes.

Question 1

Phrynoderma is primarily associated with a deficiency of which of the following?

Accepted Answer

Vitamin A

Answer

Essential fatty acid

Answer

Vitamin D

Answer

Niacin

Question 2

Itchy purple papule followed by hyperpigmentation on resolution, is seen in?

Accepted Answer

Lichen planus

Answer

Addison's disease

Answer

DM

Answer

Hypothyroidism

Question 3

Loss of intercellular cohesion between keratinocytes is referred to as?

Accepted Answer

Acantholysis

Answer

Acanthosis

Answer

Keratinolysis

Answer

Spongiosis

Question 4

Which of the following statements about spider telangiectasia is false?

Accepted Answer

More common in males

Answer

Light therapy for treatment

Answer

May be associated with liver disease

Answer

Can be caused by trauma

Question 5

Erythematous cutaneous nodules may be caused by the following except:

Accepted Answer

Herpes Simplex Virus (HSV)

Answer

Acanthamoeba

Answer

Kaposi's sarcoma

Answer

Bartonella

Question 6

A 42-year-old man was seen in the clinic because of pain and redness in his finger. Last week he had injured the finger while working in his garage. On physical examination, there is erythema, swelling, and tenderness of the second digit in the right hand. Flexion and extension of the finger were normal. A clinical diagnosis of cellulitis is made and he is prescribed cephalexin. A few days later he presents to the emergency room complaining of difficulty breathing. He has angioedema due to a drug reaction to the cephalexin. Which of the following physical findings is characteristic of this syndrome?

Accepted Answer

Involvement of lips, tongue, eyelids, genitalia, and dorsum of hands or feet

Answer

Invariably severe itching

Answer

Prolonged nature of the edema

Answer

Fluid extravasation from subcutaneous and intradermal postcapillary venules

Question 7

25-year-old male having fever and malaise for 2 weeks, arthritis of the ankle joint, and tender erythematous nodules over the shin. What is the diagnosis?

Accepted Answer

Erythema nodosum

Answer

Weber- Christian disease

Answer

Nodular Vasculitis

Answer

Hansen's disease

Question 8

Target or iris lesions are seen in:

Accepted Answer

Erythema multiforme

Answer

Urticaria

Answer

Scabies

Answer

Lichen planus

Question 9

Which of the following statements about erythema multiforme is false?

Accepted Answer

Lesions are usually asymmetrical.

Answer

Due to sulphonamide

Answer

Due to Herpes simplex

Answer

Mucous membrane involvement occurs in EM major

Question 10

Which of the following conditions is associated with acanthosis nigricans?

Accepted Answer

Type 2 Diabetes Mellitus

Answer

Obesity

Answer

Gastric adenocarcinoma

Answer

All of the options

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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