LE2 DERMA Flashcards
1
Q
- Management of atopic dermatitis, EXCEPT:
* A. Use of moisturizers
* B. Emollients
* C. Warm cool water with bath soap
* D. Anti-inflammatory drugs
A
C. Warm cool water with bath soap
Rationale: Atopic dermatitis management includes the use of moisturizers and emollients to maintain skin hydration (Options A and B). Anti-inflammatory drugs are also used to reduce inflammation (Option D). However, bathing with warm cool water and using bath soap (Option C) can strip the skin of natural oils and exacerbate dryness, which is not recommended.
2
Q
- Appropriate amount of topical agent required to cover the entire body of an adult:
* A. 50g
* B. 70g
* C. 30g
* D. 100g
A
C. 30g
Rationale: Approximately 30 grams of a topical agent are needed to cover the entire body of an average adult in one application. This is a standard measure used in dermatology to ensure adequate coverage.
3
Q
- Skin lesion end-stage variety of pruritic and eczematous disorders:
* A. Lichen Simplex Chronicus
* B. Atopic Dermatitis
* C. Contact Dermatitis
* D. Asteatotic Eczema
A
A. Lichen Simplex Chronicus
Rationale: Lichen Simplex Chronicus is a skin condition resulting from chronic scratching or rubbing, leading to thickened, leathery skin. It represents the end-stage of various pruritic and eczematous disorders.
4
Q
- Melasma presents as:
* A. Tan-brown patches on the forehead, cheeks, temples, and upper lips (sun-exposed areas)
* B. Dark, round, raised lesions on the extremities
* C. Red patches on the chest and back
* D. Itchy, flaky patches on the scalp
A
A. Tan-brown patches on the forehead, cheeks, temples, and upper lips (sun-exposed areas)
Rationale: Melasma is characterized by symmetrical, hyperpigmented macules on sun-exposed areas of the face, such as the forehead, cheeks, temples, and upper lip. It is often associated with hormonal changes and sun exposure.
5
Q
- Hyperpigmentation associated with stasis dermatitis is due to:
* A. Chronic erythrocyte extravasation leading to cutaneous hemosiderin deposition
* B. Excessive sun exposure
* C. Melanin overproduction
* D. Chronic eczema
A
A. Chronic erythrocyte extravasation leading to cutaneous hemosiderin deposition
Rationale: In stasis dermatitis, poor venous return leads to increased pressure and leakage of red blood cells into the skin (erythrocyte extravasation). The breakdown of these cells releases hemosiderin, causing hyperpigmentation.
6
Q
- Tripe palms associated with acanthosis nigricans is most common in:
* A. Bladder carcinoma
* B. Gastric adenocarcinoma
* C. Bile duct carcinoma
* D. Rectal carcinoma
A
B. Gastric adenocarcinoma
Rationale: Tripe palms and acanthosis nigricans are paraneoplastic dermatologic manifestations most commonly associated with gastric adenocarcinoma. They indicate an underlying malignancy, prompting further investigation.
7
Q
- Jaundice but the sclera is white:
* A. Carotinemia
* B. Hemochromatosis
* C. Wilson’s disease
* D. Hepatitis
A
A. Carotinemia
Rationale: Carotinemia is characterized by yellowing of the skin due to high levels of carotene but does not affect the sclera, which remains white. This differentiates it from true jaundice, where both skin and sclera are yellowed.
8
Q
- Hyperpigmentation of the skin, what workup will you do?
* A. Vitamin D
* B. C-reactive protein
* C. ALT
* D. ACTH
A
D. ACTH
Rationale: Elevated levels of adrenocorticotropic hormone (ACTH) can lead to hyperpigmentation, as seen in conditions like Addison’s disease. Measuring ACTH levels helps in diagnosing adrenal insufficiency and related disorders.
9
Q
- Hide-bound lesion is seen in:
* A. Scleroderma
* B. Psoriasis
* C. Erythema multiforme
* D. Lupus erythematosus
A
A. Scleroderma
Rationale:
A hide-bound lesion refers to skin that is tightly bound down to underlying tissues, making it feel stiff and immobile. This is characteristic of scleroderma, a connective tissue disease marked by excessive collagen deposition leading to skin thickening and hardening.
10
Q
- Café au lait spots are usually seen with this lesion in patients with:
* A. Neurofibromatosis
* B. Melanoma
* C. Psoriasis
* D. Kaposi sarcoma
A
A. Neurofibromatosis
Rationale:
Café au lait spots are light brown skin patches commonly associated with neurofibromatosis type 1. They are one of the diagnostic criteria for this genetic disorder, which also includes the development of multiple neurofibromas.
11
Q
- Meningococcemia is seen as:
* A. Hemorrhagic and necrotic lesions
* B. Bullous lesions
* C. Vesicular rash
* D. Erythematous rash
A
A. Hemorrhagic and necrotic lesions
Rationale:
Meningococcemia presents with hemorrhagic and necrotic skin lesions due to disseminated intravascular coagulation and vascular damage caused by Neisseria meningitidis infection. These lesions often appear as purpura or petechiae.
12
Q
- Kaposi sarcoma is seen as:
* A. Dark, round, papular lesions
* B. Scaly, pink patches
* C. Red, raised nodules
* D. Crusted ulcers
A
A. Dark, round, papular lesions
Rationale:
Kaposi sarcoma manifests as dark purplish to brown papular lesions on the skin and mucous membranes. These vascular tumors are associated with human herpesvirus 8 and are commonly seen in immunocompromised patients.
13
Q
- Secondary syphilis is seen as:
* A. Copper-colored papules
* B. Vesicles filled with clear fluid
* C. Red, inflamed patches
* D. Pustules on the face and neck
A
A. Copper-colored papules
Rationale:
Secondary syphilis is characterized by a diffuse, symmetric, maculopapular rash that is often copper-colored. These lesions can involve the palms and soles and are a result of systemic spread of the Treponema pallidum bacteria.
14
Q
- Primary lesion in psoriasis:
o A. Plaques with silvery micaceous scales
o B. Vesicles with clear fluid
o C. Crusted ulcers
o D. Erythematous patches
A
A. Plaques with silvery micaceous scales
Rationale:
Psoriasis is a chronic autoimmune skin condition characterized by the rapid proliferation of skin cells leading to thickened, erythematous plaques covered with silvery-white (micaceous) scales. These plaques are the primary lesions and are commonly found on the elbows, knees, scalp, and lower back.
15
Q
- Primary lesion of necrotizing vasculitis:
o A. Hemorrhagic red papules that do not blanch with pressure
o B. Bullae with clear fluid
o C. Purpuric macules
o D. Crusted ulcers
A
A. Hemorrhagic red papules that do not blanch with pressure
Rationale:
Necrotizing vasculitis involves inflammation and necrosis of blood vessel walls, leading to palpable purpura—hemorrhagic red papules that do not blanch when pressure is applied. This non-blanching property is due to extravasation of red blood cells into the skin.
16
Q
- Primary lesion in dermatophytosis herpetitis:
o A. Papules or pustules
o B. Erythematous plaques
o C. Nodules
o D. Scaly patches
A
A. Papules or pustules
Rationale:
The primary lesion in dermatophytosis herpetiformis (also referred to as Majocchi’s granuloma, a type of deep fungal infection caused by dermatophytes) is typically characterized by papules or pustules. This condition occurs when the fungal infection penetrates deeper into the hair follicles or skin layers, leading to inflammation and the formation of papules or pustules.
17
Q
- Primary lesion of erythema multiforme:
o A. Target-shaped lesions
o B. Scaly red patches
o C. Blisters on mucosal surfaces
o D. Vesicles on the palms and soles
A
A. Target-shaped lesions
Rationale:
Erythema multiforme is characterized by target or iris-shaped lesions with concentric rings of color change. These lesions typically appear on the extremities and are the primary feature of the condition.
18
Q
- KOH preparation is slightly heated to:
o A. Make fungal elements more visible
o B. Remove excess skin cells
o C. Eliminate bacteria
o D. Destroy parasites
A
A. Make fungal elements more visible
Rationale:
Heating a potassium hydroxide (KOH) preparation helps to dissolve keratin and skin cells, making fungal elements like hyphae and spores more visible under the microscope. This enhances the diagnostic accuracy for fungal infections.
19
Q
- The characteristic coral pink lesion under Wood’s light is due to:
o A. Pseudomonas
o B. Microsporum canis
o C. Corynebacterium minitissimum
o D. Varicella-zoster virus
A
C. Corynebacterium minutissimum
Rationale:
Corynebacterium minutissimum causes erythrasma, a superficial skin infection commonly found in intertriginous areas (skin folds). Under Wood’s light examination, erythrasma exhibits a coral pink fluorescence due to porphyrin production by the bacteria. This distinctive coloration helps differentiate it from other skin conditions
20
Q
- The characteristic pale blue skin lesion under Wood’s light is due to:
o A. Pseudomonas
o B. Microsporum canis
o C. Corynebacterium minitissimum
o D. Varicella-zoster virus
A
A. Pseudomonas
Rationale:
Pseudomonas aeruginosa infections can present with a pale blue fluorescence under Wood’s light. The bacterium produces pigments like pyocyanin, which emit a pale blue color when exposed to ultraviolet light. This finding aids in the diagnosis of pseudomonal skin infections, especially in wounds or burns.
21
Q
- The yellow fluorescence under Wood’s light is due to:
o A. Pseudomonas
o B. Microsporum canis
o C. Corynebacterium minitissimum
o D. Varicella-zoster virus
A
B. Microsporum canis
Rationale:
Microsporum canis and Microsporum audouinii are dermatophytes responsible for certain cases of tinea capitis (fungal scalp infections). Under Wood’s light, infected hairs fluoresce a bright yellow color. This yellow fluorescence helps in diagnosing tinea capitis caused by these specific fungi.
22
Q
- Appears white under Wood’s light:
o A. Corynebacterium minitissimum
o B. Pseudomonas
o C. Vitiligo
o D. Tinea capitis
A
C. Vitiligo
Rationale:
Vitiligo is characterized by depigmented patches due to the loss of melanocytes. Under Wood’s light examination, these areas appear bright white, providing a stark contrast to surrounding normal skin. This fluorescence enhances the visibility of depigmented areas, aiding in the assessment and diagnosis of vitiligo.
23
Q
- How long should the skin be in contact to facilitate the patch test?
* A. 6 hours
* B. 12 hours
* C. 24 hours
* D. 48 hours
A
D. 48 hours
Rationale:
In a patch test, allergens are applied to the skin under occlusive patches to identify substances causing contact dermatitis. The patches should remain in contact with the skin for 48 hours to allow sufficient time for a delayed-type hypersensitivity reaction to develop if the individual is sensitized to any of the tested allergens.
24
Q
- Diagnostic procedure used to press a microscope slide to exhibit blanching:
* A. Diascopy
* B. Biopsy
* C. Dermoscopy
* D. Patch test
A
A. Diascopy
Rationale:
Diascopy is a diagnostic technique where a transparent object, such as a microscope slide, is pressed against a skin lesion to observe color changes. This helps determine if redness is due to blood within vessels (which blanches under pressure) or due to hemorrhage (which does not blanch). Blanching indicates vascular dilation, as seen in conditions like erythema, while non-blanching suggests extravasation of blood, as in purpura.
25
12. A 50-year-old non-diabetic patient with lower extremity edema that goes away at the end of the day. Has erythematous patches:
* A. Dyshidrotic eczema
* B. Atopic dermatitis
* C. Stasis dermatitis
* D. Psoriasis
C. Stasis dermatitis
Rationale:
Stasis dermatitis occurs due to chronic venous insufficiency in the lower extremities, leading to pooling of blood, increased venous pressure, and leakage of fluid. This results in edema (which may fluctuate throughout the day) and erythematous patches on the skin. Although edema typically worsens by the day's end, individual variations can occur. The presence of lower extremity edema and erythematous skin changes in a middle-aged patient points toward stasis dermatitis.
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17. Which of the following statements correctly describes the distribution of atopic dermatitis in adults vs. children?
* A. Childhood AD is more common in flexural skin such as the antecubital and popliteal fossa, while adults frequently have localized disease manifesting as lichen simplex chronicus or hand eczema.
* B. Childhood AD primarily affects the face, scalp, and diaper area, while Adult AD is more common on the trunk and lower extremities.
* C. Adult AD is most commonly found on the neck and scalp, while childhood AD is most commonly localized to the hands and feet.
* D. In adults, atopic dermatitis is frequently found in the flexural areas, while in children it affects the palms and soles.
A. Childhood AD is more common in flexural skin such as the antecubital and popliteal fossa, while adults frequently have localized disease manifesting as lichen simplex chronicus or hand eczema.
Rationale:
The distribution of atopic dermatitis (AD) varies with age:
* In children, AD commonly affects the flexural areas such as the neck, antecubital fossae (inside elbows), popliteal fossae (behind knees), dorsum of the wrists, and flexor surfaces of the feet. This is consistent with the information provided that childhood AD is more prevalent in these flexural regions.
* In adults, while AD can also involve the flexural areas, there is a higher propensity for localized disease manifestations, including lichen simplex chronicus (thickened, lichenified plaques resulting from chronic scratching) and hand eczema.
27
18. Management of Atopic Dermatitis, EXCEPT:
* A. Warm cool water with bath soap
* B. Moisturizers
* C. Emollients
* D. Anti-inflammatory drugs
A. Warm cool water with bath soap
Rationale:
While bathing with warm or cool water is beneficial for atopic dermatitis, using regular bath soap is not recommended because it can strip the skin of natural oils, leading to increased dryness and irritation. Instead, mild, fragrance-free cleansers or soap substitutes should be used. Moisturizers (Option B), emollients (Option C), and anti-inflammatory drugs (Option D) are all appropriate treatments to manage atopic dermatitis.
28
19. Appropriate amount of topical agent required to cover the entire body of an adult:
* A. 50g
* B. 70g
* C. 30g
* D. 100g
C. 30g
Rationale:
Approximately 30 grams of a topical medication are needed to cover the entire body surface of an average adult in one application. This estimation helps in prescribing adequate amounts for treatment and ensures sufficient coverage for therapeutic effectiveness.
29
20. Skin lesion that represents the end-stage variety of pruritic and eczematous disorders:
* A. Lichen Simplex Chronicus
* B. Atopic Dermatitis
* C. Contact Dermatitis
* D. Asteatotic Eczema
A. Lichen Simplex Chronicus
Rationale:
Lichen Simplex Chronicus is the result of chronic scratching or rubbing of the skin, leading to thickened, lichenified plaques. It represents the end-stage of various pruritic (itchy) and eczematous skin disorders, where persistent irritation causes significant skin changes.
30
21. T- and B-cell hyperactivity, production of autoantibodies with specificity for nuclear antigenic determinants, and abnormalities of T-cell function occur; signs include photosensitivity and cicatricial alopecia:
* A. Dermatomyositis
* B. SLE
* C. Scleroderma
* D. CREST syndrome
B. Systemic Lupus Erythematosus (SLE)
Rationale:
Systemic Lupus Erythematosus is an autoimmune disorder characterized by hyperactivity of T and B lymphocytes, leading to the production of autoantibodies against nuclear antigens. Clinical features include photosensitivity, cicatricial alopecia (scarring hair loss), and various systemic manifestations. Abnormal T-cell function contributes to the immune dysregulation seen in SLE.
31
22. **An autoimmune disease of the connective tissue characterized by thickening of the skin due to the accumulation of collagen and injury to small arteries:**
- A. Sjogren's syndrome
- B. SLE
- C. Scleroderma
- D. Dermatomyositis
C. **Scleroderma**
**Rationale:**
Scleroderma is an autoimmune connective tissue disease characterized by excessive collagen deposition leading to skin thickening and hardening (fibrosis). It also involves injury to small arteries and arterioles, resulting in vascular abnormalities such as Raynaud's phenomenon. The accumulation of collagen affects not only the skin but can also involve internal organs, leading to systemic sclerosis.
32
23. **In dyshidrotic eczema, check for the presence of:**
- A. Vesicles on the palms and soles
- B. Lichenification on the elbows
- C. Target lesions
- D. Pustules
A. **Vesicles on the palms and soles**
**Rationale:**
Dyshidrotic eczema, also known as pompholyx, is characterized by the sudden onset of deep-seated, small vesicles on the palms, sides of the fingers, and soles of the feet. These vesicles are intensely itchy and may coalesce to form larger blisters.
33
24. **Herpes simplex I is commonly characterized by the presence of:**
- A. Vesicles
- B. Lichenification
- C. Crusts
- D. Papules
A. **Vesicles**
**Rationale:**
Herpes simplex virus type 1 (HSV-1) typically presents with grouped vesicles on an erythematous base, often around the mouth and lips (herpes labialis or "cold sores"). The vesicles are filled with clear fluid and may rupture to form shallow ulcers or crusts.
34
25. **The secondary skin lesion that is defined as the excessive accumulation of stratum corneum is:**
- A. Lichenification
- B. Crust
- C. Scale
- D. Scar
C. **Scale**
**Rationale:**
A **scale** is a flake of desquamated (shed) stratum corneum, the outermost layer of the epidermis. It represents an abnormal accumulation or shedding of keratinized cells and is a secondary lesion that can occur in various skin conditions like psoriasis and ichthyosis.
35
26. **The skin lesion defined as the loss of epidermis without an associated loss of dermis is:**
- A. Ulcer
- B. Erosion
- C. Excoriation
- D. Atrophy
B. **Erosion**
**Rationale:**
An **erosion** is a superficial loss of epidermal layers without penetration into the dermis. Erosions heal without scarring because the dermal layer, which contains the structures necessary for regeneration, remains intact.
36
27. **Jaundice but the sclera remains white is commonly seen in:**
- A. Carotenemia
- B. Hemochromatosis
- C. Hepatitis
- D. Cirrhosis
A. **Carotenemia**
**Rationale:**
**Carotenemia** is a condition characterized by yellow-orange discoloration of the skin resulting from excessive intake of carotene-rich foods like carrots, sweet potatoes, and pumpkins. Importantly, in carotenemia, the sclera (whites of the eyes) remain normal in color, which helps distinguish it from true jaundice caused by elevated bilirubin levels.
37
33. **Patients with atopic dermatitis have a deficiency of:**
- A. Desmosome
- B. Vitamin A
- C. Hemidesmosome
- D. Filaggrin
D. **Filaggrin**
**Rationale:**
Atopic dermatitis is associated with a deficiency or mutation of **filaggrin**, a key protein involved in skin barrier function. Filaggrin aggregates keratin fibers in the epidermis, contributing to the integrity and hydration of the stratum corneum. A deficiency leads to a compromised skin barrier, increased transepidermal water loss, and heightened susceptibility to allergens and irritants, which exacerbates atopic dermatitis symptoms.
38
34. **Which conditions exhibit Nikolsky's sign?**
- A. Pemphigus vulgaris
- B. Linear IgA disease
- C. Bullous pemphigoid
- D. Pemphigoid gestationis
A. **Pemphigus vulgaris**
**Rationale:**
**Nikolsky's sign** is positive when slight pressure or rubbing on the skin causes the epidermis to shear off, indicating a plane of cleavage within the skin layers. **Pemphigus vulgaris** is an autoimmune blistering disorder where autoantibodies target desmoglein-3, disrupting cell adhesion between keratinocytes and leading to intraepidermal blistering. This results in a positive Nikolsky's sign.
39
35. **A classic sign of meningococcal septicemia is:**
- A. Papules/Petechiae
- B. Blisters
- C. Vesicles
- D. Erythematous rash
A. **Papules/Petechiae**
**Rationale:**
**Meningococcal septicemia**, caused by *Neisseria meningitidis*, often presents with a characteristic rash of **petechiae** and **purpura** due to vascular damage and disseminated intravascular coagulation. These lesions are small, non-blanching red or purple spots resulting from bleeding under the skin. The presence of petechiae in a febrile patient is a medical emergency requiring prompt treatment.
40
36. **This patient's condition is associated with:**
- A. Cervical cancer
- B. Kaposi sarcoma
- C. Gastric adenocarcinoma
- D. Carcinoma of the bladder
C. **Gastric adenocarcinoma**
**Rationale:**
Certain skin conditions serve as paraneoplastic markers for internal malignancies. For instance, the sudden appearance of **acanthosis nigricans** or **tripe palms** (velvety thickening of the skin on the palms) can be associated with **gastric adenocarcinoma**. These dermatologic signs warrant evaluation for an underlying malignancy, particularly of the gastrointestinal tract.
41
37. **The Lesser-Trelat sign is manifested as:**
- A. Sudden eruption of multiple seborrheic keratoses
- B. Widespread vesicles on the trunk
- C. Rapid development of multiple actinic keratoses
- D. Multiple patches of erythema
A. **Sudden eruption of multiple seborrheic keratoses**
**Rationale:**
The **Leser-Trélat sign** refers to the abrupt appearance of numerous **seborrheic keratoses**, which are benign skin growths. This sudden eruption is often a paraneoplastic phenomenon associated with internal malignancies, most commonly **gastric adenocarcinoma**. Recognition of this sign is important for early detection of potential cancers.
42
38. **The large (greater than 1 cm in diameter) flat-topped raised lesion is called:**
- A. Plaque
- B. Nodule
- C. Papule
- D. Vesicle
A. **Plaque**
**Rationale:**
A **plaque** is a palpable, elevated, solid lesion greater than 1 cm in diameter, often formed by the confluence of papules. It has a flat top and is commonly seen in conditions like psoriasis.
43
39. **This symptom is uncommon in reflux esophagitis and raises the possibility of an esophageal infection:**
- A. Odynophagia
- B. Chest pain
- C. Regurgitation
- D. Dysphagia
A. **Odynophagia**
**Rationale:**
**Odynophagia**, or painful swallowing, is not typical of gastroesophageal reflux disease (GERD) or reflux esophagitis. When present, it suggests mucosal damage severe enough to cause pain, often due to an **esophageal infection** such as candidiasis, herpes simplex virus, or cytomegalovirus esophagitis, especially in immunocompromised individuals.
44
40. **Reduced prostaglandins secondary to NSAID use causes:**
- A. Decreased gastric mucosal blood flow
- B. Gastric hypomotility
- C. Increase in nitric oxide
- D. Decrease in pro-inflammatory mediators
A. **Decreased gastric mucosal blood flow**
**Rationale:**
NSAIDs inhibit cyclooxygenase enzymes, reducing prostaglandin synthesis. Prostaglandins in the gastric mucosa promote protective mechanisms such as mucus and bicarbonate secretion and **maintain mucosal blood flow**. A decrease in prostaglandins leads to **reduced gastric mucosal blood flow**, compromising the mucosal barrier and increasing the risk of gastric ulcers.
45
41. **The "Fir tree pattern" is characteristic of which condition?**
- A. Pityriasis rosea
- B. Tinea versicolor
- C. Herpes Zoster
- D. Candidiasis
A. **Pityriasis rosea**
**Rationale:**
Pityriasis rosea is a self-limiting skin condition that often begins with a single "herald patch" followed by a secondary rash. The rash typically spreads along the lines of skin cleavage (Langer's lines) on the back, creating a pattern that resembles a **"fir tree"** or **"Christmas tree."** This distribution is distinctive and helps differentiate pityriasis rosea from other skin conditions.
46
42. **Honey-colored lesions, the causative agent is:**
- A. Staphylococcus aureus
- B. Streptococcus aureus
- C. Corynebacterium diphtheriae
- D. Both A and B
D. **Both A and B**
**Rationale:**
Honey-colored crusts are characteristic of **impetigo**, a highly contagious superficial skin infection. The primary causative agents are:
- **A. Staphylococcus aureus**
- **B. Streptococcus pyogenes** (commonly known as Group A Streptococcus)
Both bacteria can cause impetigo, and co-infection is possible. Therefore, **both A and B** are correct.
47
45. **Indurated and hyperkeratotic lesions most commonly found on the lower lips and ears are indicative of:**
- A. Basal Cell Carcinoma
- B. Squamous Cell Carcinoma
- C. Melanoma
- D. Actinic Keratosis
B. **Squamous Cell Carcinoma**
**Rationale:**
**Squamous Cell Carcinoma (SCC)** is a malignant tumor arising from keratinizing cells of the epidermis. It often presents as indurated (firm), hyperkeratotic (thickened, scaly) lesions or ulcers on sun-exposed areas such as the **lower lips** and **ears**. Chronic sun exposure is a significant risk factor. SCC can be aggressive and metastasize if not treated promptly.
48
46. **Condition associated with exposure to sunlight due to uroporphyrinogen decarboxylase deficiency:**
- A. Porphyria Cutanea Tarda
- B. Xeroderma Pigmentosum
- C. Pellagra
- D. Erythropoietic protoporphyria
A. **Porphyria Cutanea Tarda**
**Rationale:**
**Porphyria Cutanea Tarda (PCT)** is the most common type of porphyria and results from a deficiency of the enzyme **uroporphyrinogen decarboxylase**. This deficiency leads to the accumulation of photosensitive porphyrins in the skin. When exposed to sunlight, patients develop blistering, fragility, and hyperpigmentation of the skin.
49
49. **Contact dermatitis is a form of:**
- A. IgE-mediated reaction
- B. Cytotoxic reaction
- C. Immune complex reaction
- D. Delayed cell-mediated reaction
D. **Delayed cell-mediated reaction**
**Rationale:**
Contact dermatitis is a **Type IV hypersensitivity reaction**, which is a **delayed cell-mediated immune response**. It involves sensitized **T lymphocytes** reacting to an antigen (e.g., poison ivy, nickel) upon re-exposure, leading to skin inflammation typically 48–72 hours after contact.
50
50. **The reaction shown by patients treated with penicillin for syphilis, a type III cytotoxic reaction, is:**
- A. Stevens-Johnson syndrome
- B. Jarisch-Herxheimer reaction
- C. Lyell syndrome
- D. Serum sickness
B. **Jarisch-Herxheimer reaction**
**Rationale:**
The **Jarisch-Herxheimer reaction** is an acute febrile response that occurs within hours after starting antibiotic treatment for syphilis. Symptoms include fever, chills, headache, muscle aches, and a worsening of syphilitic lesions. It results from the rapid lysis of **Treponema pallidum** bacteria, leading to the release of endotoxins and cytokines. Although the reaction is not a classic **Type III hypersensitivity** (immune complex-mediated) or **cytotoxic** reaction, it is the reaction commonly associated with penicillin treatment for syphilis.
51
53. **Characteristic of phototoxic reactions:**
- A. Less incidence than photoallergic reactions
- B. Occurs 1-3 days after exposure
- C. Seen in exposed areas
- D. Seen in unexposed areas
C. **Seen in exposed areas**
**Rationale:**
Phototoxic reactions occur when a chemical agent (photosensitizer) on the skin absorbs ultraviolet (UV) light and causes direct cellular damage. Key characteristics of phototoxic reactions include:
52
54. **A gene mutation in encoding for filaggrin is associated with:**
- A. Atopic Dermatitis
- B. Dermatomyositis
- C. Scleroderma
- D. Psoriasis
A. **Atopic Dermatitis**
**Rationale:**
**Filaggrin** is a crucial protein involved in the skin's barrier function, helping to retain moisture and protect against external allergens and irritants. Mutations in the gene encoding filaggrin lead to a deficiency of this protein, resulting in:
53
59. **An erythematous patch with a clearing center and advancing borders is characteristic of:**
- A. Tinea versicolor
- B. Dermatophytosis
- C. Psoriasis
- D. Eczema
B. **Dermatophytosis**
**Rationale:**
**Dermatophytosis**, commonly known as ringworm, is a fungal infection of the skin caused by dermatophytes. It presents as:
54
60. **HPV types most frequently associated with cervical carcinoma are:**
- A. 16, 18
- B. 31, 33
- C. 35, 39
- D. 40, 45
A. **16, 18**
**Rationale:**
Human Papillomavirus (HPV) types are classified based on their oncogenic potential:
- **High-risk HPV types:** HPV **16** and **18** are the most oncogenic and are responsible for approximately 70% of cervical cancer cases worldwide.
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63. **A 26-year-old male complains of multiple hypopigmented, slightly scaly macules and patches on his chest and back. He discovered them after spending a day swimming. He denies feeling any symptoms from the rashes, and his friends do not have similar lesions. Management of this condition should include:**
- A. Use of sulfur soap
- B. Phototherapy using narrow band UVA
- C. Application of topical corticosteroid
- D. Application of sunscreen
:** A. **Use of sulfur soap**
**Rationale:**
The described symptoms are characteristic of **tinea versicolor**, a superficial fungal infection caused by *Malassezia* species. It presents as hypopigmented or hyperpigmented, slightly scaly macules and patches on the trunk, especially noticeable after sun exposure due to the affected areas not tanning.
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64. **A seven-year-old boy came to school with small vesicles on an erythematous base. He had a fever and sore throat. Most of the rashes started on his face and chest, with some on his arms and palms. The appropriate course of action should include:**
- A. Isolation of the child
- B. Application of topical antibiotic combined with mild corticosteroids
- C. Review what he has eaten for the past 48 hours
- D. Order a complete blood count
- E. Throat swab, gram staining is necessary
A. **Isolation of the child**
**Rationale:**
The boy likely has **varicella (chickenpox)**, characterized by:
- **Small vesicles on an erythematous base ("dew drops on a rose petal")**
- **Fever and sore throat**
- **Rash starting on the face and chest, spreading to extremities**
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65. **Diascopy will help differentiate:**
- A. Erythema from tinea capitis
- B. Malignant melanoma from a benign nevus
- C. Intravascular and extravascular cause of erythema
- D. Pemphigus vulgaris from bullous pemphigoid
C. **Intravascular and extravascular cause of erythema**
**Rationale:**
**Diascopy** involves pressing a clear glass slide against a skin lesion to observe blanching:
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66. **A 23-year-old female complains of an erythematous patch on both cheeks and the bridge of the nose after a day at the beach. Examination shows sparing of the nasolabial fold and absence of scaling. You will tell her:**
- A. Avoid sun exposure
- B. She may apply a mild antifungal cream at bedtime
- C. Metronidazole gel may help
- D. It is common and may be inherited, with recurrences triggered by stress, illness, or changes in the weather
C. Metronidazole gel may help
Rationale:
The patient's presentation is consistent with acne rosacea, a chronic inflammatory skin condition that primarily affects the central face, including the cheeks and bridge of the nose. Key features supporting this diagnosis include:
* Erythematous patches on the cheeks and bridge of the nose: Central facial involvement is characteristic of rosacea.
* Sparing of the nasolabial folds: Rosacea often spares the nasolabial folds, whereas conditions like seborrheic dermatitis typically involve these areas.
* Absence of scaling: Rosacea lesions usually lack scaling, differentiating it from conditions like lupus erythematosus or seborrheic dermatitis.
* Triggered by sun exposure: Sunlight is a common exacerbating factor in rosacea.
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67. **Patients with atopic dermatitis have a deficiency of:**
- A. Filaggrin
- B. Desmosome
- C. Vitamin A
- D. Hemidesmosome
A. **Filaggrin**
**Rationale:**
**Filaggrin** is a protein essential for skin barrier function:
- **Role:** Aggregates keratin fibers, contributes to skin hydration.
- **Deficiency:** Leads to impaired skin barrier, increased water loss, and susceptibility to allergens.
- **Association with atopic dermatitis:** Filaggrin gene mutations are linked to atopic dermatitis development.
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68. **A 72-year-old female was convinced by a hairdresser to dye her hair for the first time. During the application, she complained of stinging and itching on the area where the dye was applied. She most likely has:**
- A. Irritant contact dermatitis
- B. Atopic dermatitis
- C. Seborrheic dermatitis of the scalp
- D. Allergic contact dermatitis
A. **Irritant contact dermatitis**
**Rationale:**
**Irritant contact dermatitis:**
- **Immediate onset of symptoms:** Stinging and itching during application.
- **Non-immunologic reaction:** Direct chemical irritation to the skin.
- **Common irritants:** Hair dyes, especially during first-time exposure.
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71. **These conditions exhibit Nikolsky's sign:**
- A. Pemphigus vulgaris
- B. Linear IgA disease
- C. Bullous pemphigoid
- D. Pemphigoid gestationis
A. **Pemphigus vulgaris**
**Rationale:**
**Nikolsky's sign** is positive when gentle lateral pressure on the skin causes the epidermis to shear off, indicating a plane of cleavage within the epidermis. This sign is characteristic of **pemphigus vulgaris**, an autoimmune blistering disease where antibodies target desmoglein-3, a protein critical for cell-to-cell adhesion in the epidermis. This results in intraepidermal blistering and a positive Nikolsky's sign.
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72. **A 40-year-old female complains of difficulty raising her arms. On examination, she has reddish violaceous patches around her eyes. You will also look for:**
- A. Erythematous grouped papules on her knuckles
- B. Clubbing of fingernails
- C. Oil spots on her nails
- D. Hide-bound skin
A. **Erythematous grouped papules on her knuckles**
**Rationale:**
The patient's symptoms suggest **dermatomyositis**, an autoimmune disease characterized by muscle weakness and distinctive skin manifestations. The **heliotrope rash** is a reddish-violaceous discoloration around the eyes. Another hallmark skin finding is **Gottron's papules**, which are erythematous or violaceous papules located over the knuckles (metacarpophalangeal and interphalangeal joints).
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79. **Keratinous cysts on the face and scalp, along with multiple osteomas, should necessitate an investigation of:**
- A. Gastrointestinal system
- B. Lungs
- C. Bone marrow
- D. Bladder
A. **Gastrointestinal system**
**Rationale:**
The presence of keratinous cysts (epidermoid cysts) on the face and scalp, coupled with multiple osteomas (benign bone tumors), is characteristic of **Gardner's syndrome**, a variant of familial adenomatous polyposis (FAP). Gardner's syndrome includes:
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80. **Dermatologic manifestations of Reiter's syndrome include:**
- A. Erythematous nodules on the lower extremities
- B. Pus-filled sores on palms and soles
- C. Purpura on the lower extremities
- D. Buccal mucosa erosions
B. **Pus-filled sores on palms and soles**
**Rationale:**
**Reiter's syndrome**, now more commonly referred to as **reactive arthritis**, is characterized by the triad of arthritis, urethritis, and conjunctivitis. Dermatologic manifestations include:
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89. **A patient complained of chronic pruritus with scaly skin lesions on his arms and chest. He was started on methotrexate per orem given weekly. Which of the following is NOT a potential adverse event when using methotrexate?**
- A. Observe for any pulmonary symptoms for possible lung toxicity
- B. Monitor for visual changes for possible ophthalmologic effects
- C. Monitor the liver function test for possible hepatotoxicity
- D. Monitor the complete blood count for possible pancytopenia
B. **Monitor for visual changes for possible ophthalmologic effects**
**Rationale:**
Methotrexate is a systemic antimetabolite used in the treatment of psoriasis and has several known adverse effects that require monitoring:
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90. **The FDA-approved systemic therapy for Psoriasis that is given twice a day:**
- A. Methotrexate
- B. Acitretin
- C. Cyclosporine and apremilast
- D. AOTA (All of the above)
C. **Cyclosporine and apremilast**
**Rationale:**
According to **Table 53-3**, the dosing frequency for FDA-approved systemic therapies for psoriasis is as follows:
- **Methotrexate:** Oral, **weekly**
- **Acitretin:** Oral, **daily**
- **Cyclosporine:** Oral, **twice daily**
- **Apremilast:** Oral, **twice daily**
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91. **The FDA-approved systemic therapy for Psoriasis that has the potential to lead to birth defects if given to women of child-bearing age:**
- A. Only cyclosporine
- B. Cyclosporine and apremilast
- C. Methotrexate and acitretin
- D. Only methotrexate
C. **Methotrexate and acitretin (teratogenic)**
**Rationale:**
Both **methotrexate** and **acitretin** are known **teratogens** and can cause serious birth defects if administered to pregnant women or women of childbearing potential without effective contraception:
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92. **A patient came in with honey-colored crusted papules on the borders of the mouth, with some plaques in other parts of the body. The most likely diagnosis is:**
- A. Dermatophytosis
- B. Tinea versicolor
- C. Candidiasis
- D. Impetigo
D. **Impetigo**
**Rationale:**
Impetigo is a common superficial bacterial skin infection primarily affecting children but can occur at any age. It is characterized by:
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95. **Which of the following are considered papulosquamous disorders?**
- A. Lichen planus
- B. Psoriasis
- C. All of the above
- D. None of the above
- E. Pityriasis rosea and dermatophytosis
C. **All of the above**
**Rationale:**
Papulosquamous disorders are skin conditions characterized by papules and scales. They include:
- **Psoriasis:** Chronic autoimmune condition with erythematous plaques and silvery scales.
- **Lichen planus:** Presents with violaceous, flat-topped papules and Wickham's striae.
- **Pityriasis rosea:** Features a herald patch followed by a "Christmas tree" pattern of scaly lesions.
- **Dermatophytosis:** Fungal infections like tinea corporis can present with scaly, annular lesions.
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96. **This is an autoimmune disease that results in the destruction of melanocytes. Distribution of skin discoloration can be symmetrical, perioral, or segmental:**
- A. Vitiligo
- B. Chemical leukoderma
- C. Idiopathic guttate hypomelanosis
- D. Piebaldism
A. **Vitiligo**
**Rationale:**
**Vitiligo** is characterized by:
- **Autoimmune destruction of melanocytes:** Leading to depigmented macules and patches.
- **Variable distribution:** Can be symmetrical, segmental, focal, or generalized.
- **Common sites:** Face (perioral areas), hands, wrists, axillae, and genitalia.
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97. **A patient sought consultation due to persistent erythema of her leg with scaling and pruritus. She was diagnosed with deep venous thrombosis 10 months ago and was treated accordingly. The typical initial site of involvement is:**
- A. Dorsum of the foot
- B. Plantar aspect of the foot, particularly on the pressure points
- C. The lateral aspect of the ankle, over a distended vein
- D. The medial aspect of the ankle, often over a distended vein
D. **The medial aspect of the ankle, often over a distended vein**
**Rationale:**
The patient likely has **stasis dermatitis**, which arises from chronic venous insufficiency often following deep vein thrombosis (DVT). Key features include:
- **Initial involvement of the medial ankle:** Due to venous hypertension affecting the great saphenous vein territory.
- **Erythema, scaling, and pruritus:** Common symptoms of stasis dermatitis.
- **Overlying distended veins:** Venous insufficiency leads to varicosities and skin changes.
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98. **Endocrine disorders that may cause diffuse hyperpigmentation, EXCEPT:**
- A. Nelson syndrome
- B. Systemic sclerosis
- C. Hyperthyroidism
- D. Addison's disease
B. **Systemic sclerosis**
**Rationale:**
Endocrine disorders causing diffuse hyperpigmentation include:
- **Addison's disease (Option D):** Adrenal insufficiency leading to increased ACTH and melanocyte-stimulating hormone (MSH), causing hyperpigmentation.
- **Nelson syndrome (Option A):** After adrenalectomy, excessive ACTH production leads to hyperpigmentation.
- **Hyperthyroidism (Option C):** Can cause skin hyperpigmentation due to increased metabolism and blood flow.
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99. **A wheal is distinguished from other primary skin lesions by the presence of:**
- A. A raised erythematous or edematous papule or plaque, usually representing short-lived vasodilation and vasopermeability
- B. A small fluid-filled lesion less than 0.5 cm in diameter raised above the surrounding skin
- C. A small fluid-filled lesion filled with leukocytes
- D. A small, firm papule with a central punctum
A. **A raised erythematous or edematous papule or plaque, usually representing short-lived vasodilation and vasopermeability**
**Rationale:**
A **wheal** (also known as a hive) is characterized by:
- **Transient swelling:** Due to edema in the dermis.
- **Erythema and itching:** Resulting from vasodilation and increased vascular permeability.
- **Short-lived nature:** Wheals often resolve within 24 hours.
The other options describe different lesions:
- **Option B:** Describes a **vesicle**, a small fluid-filled blister.
- **Option C:** Describes a **pustule**, filled with purulent material.
- **Option D:** Could describe a **papule** or possibly a **comedone** if the central punctum is present.
