Basic Dermatology Practice Questions

Q: Miliaria arises from obstruction of ?

Eccrine sweat glands. ***Eccrine sweat glands*** - Miliaria, commonly known as **prickly heat**, occurs due to the obstruction of the **eccrine sweat ducts**. - This obstruction traps sweat beneath the skin, leading to inflammation and characteristic rash. *Apocrine sweat glands* - **Apocrine glands** are primarily located in the axillae and anogenital region and are associated with body odor, not miliaria. - Obstruction of apocrine glands can lead to conditions like **hidradenitis suppurativa**, which is distinct from miliaria. *Sebaceous glands* - **Sebaceous glands** produce sebum and are responsible for conditions like **acne vulgaris** when their ducts become clogged. - They are not involved in sweat production or the pathology of miliaria. *Ectopic sebaceous glands* - **Ectopic sebaceous glands** are sebaceous glands found in unusual locations, such as Fordyce spots in the mouth or Montgomery glands in the areola. - While they produce sebum, their obstruction is unrelated to the development of miliaria.

Q: What type of cell are Tzanck cells commonly associated with in skin conditions?

Keratinocyte. ***Keratinocyte*** - **Tzanck cells** are **acantholytic keratinocytes** characterized by loss of intercellular connections, resulting in rounded cells with **large nuclei** and **perinuclear halos**. - They are classically seen in **pemphigus vulgaris** and other acantholytic disorders on **Tzanck smear** preparation. - The Tzanck smear is a simple bedside diagnostic test where the base of a blister is scraped and examined microscopically after staining. *Fibroblast* - **Fibroblasts** are mesenchymal cells in the **dermis** that produce **collagen** and extracellular matrix components. - They are not epithelial cells and do not undergo acantholysis to form Tzanck cells. *Neutrophil* - **Neutrophils** are polymorphonuclear leukocytes involved in acute inflammatory responses and fighting bacterial infections. - They may infiltrate skin lesions but do not transform into Tzanck cells, which are specifically altered keratinocytes. *Lymphocyte* - **Lymphocytes** (T cells and B cells) are immune cells involved in **adaptive immunity**. - They are not the cell type from which Tzanck cells originate; Tzanck cells are acantholytic epidermal keratinocytes.

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: Richner-Hanhart syndrome is characterized by which of the following?

Ocular and cutaneous features. ***Ocular and cutaneous features*** - **Richner-Hanhart syndrome**, also known as **Tyrosinemia type II**, is characterized by the classic triad of **painful hyperkeratotic plaques** on the palms and soles (cutaneous features), **corneal ulcers** or **dendritic keratitis** (ocular features), and **variable neurological involvement**. - These features arise from the accumulation of **tyrosine** due to a deficiency of the enzyme **hepatic tyrosine aminotransferase (TAT)**. - The **ocular and cutaneous manifestations** are the hallmark features that define this syndrome. *Autosomal dominant* - Richner-Hanhart syndrome is inherited in an **autosomal recessive** pattern, meaning two copies of the defective gene (TAT gene on chromosome 16) are required for the condition to manifest. - An **autosomal dominant** inheritance pattern would mean only one copy of the defective gene is sufficient to cause the disorder. *Associated with abnormality in lipid metabolism* - The syndrome is an inborn error of **amino acid metabolism**, specifically involving **tyrosine**, not lipid metabolism. - Diseases associated with abnormality in **lipid metabolism** include conditions like Gaucher disease, Niemann-Pick disease, or Fabry disease. *Never associated with neurological involvement* - This is **incorrect**. **Neurological involvement** including intellectual disability, developmental delay, seizures, and behavioral problems occurs in **30-50% of cases**. - The accumulation of **tyrosine** and its metabolites (particularly tyrosine crystals) can be **neurotoxic**, leading to varying degrees of neurological impairment. - Early dietary restriction of tyrosine and phenylalanine can prevent or minimize neurological complications.

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

Miliaria arises from obstruction of ?

Accepted Answer

Eccrine sweat glands

Answer

Apocrine sweat glands

Answer

Sebaceous glands

Answer

Ectopic sebaceous glands

Question 2

What type of cell are Tzanck cells commonly associated with in skin conditions?

Accepted Answer

Keratinocyte

Answer

Neutrophil

Answer

Lymphocyte

Answer

Fibroblast

Question 3

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 4

Richner-Hanhart syndrome is characterized by which of the following?

Accepted Answer

Ocular and cutaneous features

Answer

Autosomal dominant

Answer

Associated with abnormality in lipid metabolism

Answer

Never associated with neurological involvement

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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