Photosensitive Eczemas — MCQs
A 40 year old woman presents with a 2 year history of erythematous papulopustular lesions on convexities of the face. There is a background of erythema & telangiectasia. The most likely diagnosis is –
A 70-year-old man comes to the emergency department because of a skin rash and severe itching. He appears ill; there is a generalized skin rash that is scaly, erythematous, and thickened. His palms, soles, and scalp are also involved. Which of the following is the most likely diagnosis?
Which of the following statements about actinic lichen planus is false?
A patient presents with a skin rash that is exaggerated on sun exposure. What is the repair mechanism involved in this condition?
A child presents with a rash in the neck folds as shown in the image. The area appears erythematous with satellite lesions and maceration. What is the most likely diagnosis?
Dermatological manifestation of which of the following diseases?
An 8-year-old girl has extreme photosensitivity since birth. She has recently been diagnosed with skin cancer. What is the diagnosis?
A 6-year-old child born to consanguinity has pallor and intolerance to sunlight. His urine was exposed to Wood's light. Probable diagnosis is:
A 22-year-old female presents with dry papules in the seborrheic areas, especially in the summer. Her father also has a history of similar lesions. What is the most probable diagnosis?
Spongiosis is a characteristic histological finding in which of the following conditions?
Photosensitive Eczemas Indian Medical PG Practice Questions and MCQs
Question 1: A 40 year old woman presents with a 2 year history of erythematous papulopustular lesions on convexities of the face. There is a background of erythema & telangiectasia. The most likely diagnosis is –
- A. Polymorphic light eruption
- B. Acne vulgaris
- C. Acne rosacea (Correct Answer)
- D. SLE
Explanation: ***Acne rosacea*** - This condition presents with **erythematous papulopustular lesions**, background **erythema**, and **telangiectasias** predominantly on the convexities of the face, which is a classic presentation for rosacea. - The absence of **comedones** (blackheads/whiteheads) helps differentiate it from acne vulgaris. *Polymorphic light eruption* - This is a recurring skin rash triggered by **sun exposure**, presenting as itchy papules, plaques, or vesicles, usually appearing a few hours after exposure. - Unlike rosacea, it does not typically feature permanent facial erythema or telangiectasias and is more directly linked to UV exposure episodes. *Acne vulgaris* - While it features papules and pustules, **acne vulgaris** is characterized by the presence of **comedones** (blackheads and whiteheads), which are not described in the patient's presentation. - It also does not typically involve the prominent background erythema and telangiectasias seen in rosacea. *SLE* - Systemic lupus erythematosus (SLE) can cause a **malar or 'butterfly' rash** across the nose and cheeks, but it is typically a fixed erythema, sometimes with scaling, and does not usually involve papulopustular lesions or telangiectasias as a primary feature. - SLE often has systemic symptoms (e.g., joint pain, fatigue) that are not mentioned, and skin lesions can be photosensitive but are not typically pustular.
Question 2: A 70-year-old man comes to the emergency department because of a skin rash and severe itching. He appears ill; there is a generalized skin rash that is scaly, erythematous, and thickened. His palms, soles, and scalp are also involved. Which of the following is the most likely diagnosis?
- A. erythroderma (exfoliative dermatitis) (Correct Answer)
- B. pemphigus vulgaris
- C. dermatitis herpetiformis
- D. rosacea
Explanation: ***erythroderma (exfoliative dermatitis)*** - Erythroderma is characterized by a **generalized erythematous (red), scaly, and thickened skin rash** covering more than 90% of the body surface, accompanied by **severe itching**. - This condition is often associated with a **systemic illness**, and the patient's description of "appears ill" further supports this diagnosis. *pemphigus vulgaris* - Pemphigus vulgaris typically presents with **flaccid blisters** and erosions, particularly affecting mucous membranes, which are not described here. - While it can be widespread, the primary lesion is a **blister** rather than diffuse erythema and scaling. *dermatitis herpetiformis* - Dermatitis herpetiformis is characterized by intensely **pruritic (itchy) papules and vesicles** typically found on the extensor surfaces (e.g., elbows, knees, buttocks). - It is strongly associated with **celiac disease** and does not present as a generalized scaly, erythematous thickening. *rosacea* - Rosacea primarily affects the **face**, causing **erythema**, flushing, papules, and pustules, often sparing the palms, soles, and scalp. - It is not characterized by generalized scaling, thickening, or severe itching over the entire body.
Question 3: Which of the following statements about actinic lichen planus is false?
- A. Associated with severe pruritus (Correct Answer)
- B. Violaceous brown papules
- C. Usually affects exposed areas of body
- D. Autoimmune etiology
Explanation: ***Associated with severe pruritus*** - While other forms of lichen planus, especially the typical cutaneous type, are often associated with **severe pruritus**, actinic lichen planus is typically characterized by **mild or absent pruritus**. - Its presentation is often more focused on pigmentary changes and papules in sun-exposed areas rather than intense itching. *Autoimmune etiology* - **Lichen planus**, including its actinic variant, is recognized as an **autoimmune disease**. - It involves a **T-cell-mediated immune response** against basal keratinocytes. *Violaceous brown papules* - Actinic lichen planus commonly presents with **violaceous, brown, or hyperpigmented papules and plaques**. - These lesions often exhibit a subtle **annular or reticulated pattern**. *Usually affects exposed areas of body* - As its name suggests ("actinic" referring to light), this variant of lichen planus preferentially affects **sun-exposed areas** such as the face, neck, and dorsal hands. - This distribution distinguishes it from classic lichen planus, which can occur anywhere but often affects the flexor surfaces of the wrists, ankles, and oral mucosa.
Question 4: A patient presents with a skin rash that is exaggerated on sun exposure. What is the repair mechanism involved in this condition?
- A. Nucleotide excision repair (Correct Answer)
- B. Base excision repair
- C. Mismatch repair
- D. Double stranded DNA break repair
Explanation: ***Nucleotide excision repair*** - This mechanism is responsible for repairing **bulky lesions** in DNA, such as **pyrimidine dimers** caused by **UV radiation** from sun exposure. - Patients with defects in nucleotide excision repair (e.g., **xeroderma pigmentosum**) are highly sensitive to sunlight and develop skin rashes, pigment changes, and skin cancers. *Base excision repair* - This pathway primarily corrects **small damaged bases** that do not cause significant distortion of the DNA helix, such as deaminated, oxidized, or alkylated bases. - It does not primarily address the bulky lesions induced by UV light that cause exaggerated sun sensitivity. *Mismatch repair* - This system corrects errors, like **mismatched base pairs**, that are incorporated during DNA replication. - It is not directly involved in repairing DNA damage caused by environmental factors like UV radiation. *Double stranded DNA break repair* - This mechanism repairs **double-strand breaks** in DNA, which are highly deleterious lesions caused by ionizing radiation or oxidative stress. - While critical for genome stability, it is not the primary repair pathway for UV-induced DNA lesions or the direct cause of sun sensitivity.
Question 5: A child presents with a rash in the neck folds as shown in the image. The area appears erythematous with satellite lesions and maceration. What is the most likely diagnosis?
- A. Intertrigo (Correct Answer)
- B. Heat rash
- C. Eczema
- D. Impetigo
Explanation: ***Intertrigo*** - The image shows a reddened, inflamed rash in skin folds (neck creases), which is characteristic of **intertrigo**. This condition results from skin-on-skin friction, moisture, and warmth. - The rash appears to have satellite lesions and a somewhat macerated appearance, which would be consistent with secondary fungal (e.g., Candida) or bacterial infection, common complications of intertrigo. *Heat rash* - **Heat rash (miliaria)** typically presents as small, itchy red bumps or clear blisters, often found in areas prone to sweating. - While it can occur in skin folds, the diffuse, raw-looking erythema and presence of potential satellite lesions shown in the image are less typical for simple heat rash. *Eczema* - **Eczema (atopic dermatitis)** is characterized by dry, itchy, inflamed skin, often with scaling, crusting, or lichenification during chronic stages. - While eczema can affect skin folds, the appearance in the image (intense redness, maceration, potential satellite lesions) is more suggestive of an irritant or infectious process like intertrigo rather than typical eczema. *Impetigo* - **Impetigo** is a bacterial skin infection characterized by honey-colored crusts, vesicles, or bullae, typically appearing anywhere on the body, especially around the nose and mouth. - The rash in the image lacks the characteristic honey-colored crusts or vesiculobullous lesions associated with impetigo.
Question 6: Dermatological manifestation of which of the following diseases?
- A. Photo dermatitis
- B. Pellagra (Correct Answer)
- C. Acrodermatitis enteropathica
- D. Vitamin B deficiency
Explanation: ***Pellagra*** - The image shows a classic "butterfly" rash on the face, specifically a photosensitive dermatitis, which is a hallmark of **pellagra**. - Pellagra is caused by a deficiency of **niacin (vitamin B3)**, characterized by the "3 D's": **dermatitis**, **diarrhea**, and **dementia**. *Photo dermatitis* - While pellagra often presents with photosensitive dermatitis, "photo dermatitis" is a general term for **skin inflammation caused by light exposure** and not a specific disease itself. - It could be caused by various factors, including medication, immune reactions, or other underlying conditions, but the pattern seen here is highly suggestive of pellagra. *Acrodermatitis enteropathica* - This condition is a **hereditary zinc deficiency** that typically presents with a periorificial and acral dermatitis. - The skin lesions are typically **vesicular-pustular or eczematous** and do not usually have the distinct butterfly pattern of photosensitive dermatitis seen in the image. *Vitamin B deficiency* - While pellagra is a vitamin B **(niacin, B3)** deficiency, this option is too broad. - Other vitamin B deficiencies, such as **riboflavin (B2)** or **pyridoxine (B6)** deficiency, have different dermatological manifestations like angular cheilitis, glossitis, or seborrheic dermatitis, but not the characteristic facial rash seen here.
Question 7: An 8-year-old girl has extreme photosensitivity since birth. She has recently been diagnosed with skin cancer. What is the diagnosis?
- A. Xeroderma Pigmentosum (Correct Answer)
- B. Bloom syndrome
- C. Griscelli syndrome
- D. Chediak Higashi syndrome
Explanation: ***Xeroderma Pigmentosum*** - This condition is characterized by an extreme sensitivity to **ultraviolet (UV) light** from birth due to defects in **DNA repair mechanisms**, leading to severe sunburns, pigmentary changes (freckles, hypopigmented macules), and a high risk of developing **skin cancers** at a young age. - The history of extreme photosensitivity since birth and the diagnosis of skin cancer in an 8-year-old girl is highly indicative of Xeroderma Pigmentosum. *Bloom syndrome* - Bloom syndrome is an inherited disorder characterized by **stunted growth**, a **photosensitive facial rash (telangiectatic erythema)**, and a predisposition to **various cancers**, including leukemia and lymphomas. - While photosensitivity and cancer risk are present, the extreme skin damage and early onset of specific skin cancers (as opposed to leukemias/lymphomas often seen in Bloom) make Xeroderma Pigmentosum a more fitting diagnosis. *Griscelli syndrome* - Griscelli syndrome is a rare autosomal recessive disorder characterized by **partial albinism**, immunodeficiency, and neurological impairment. - While it involves pigmentary abnormalities, it does not typically present with the extreme photosensitivity or the very early skin cancer development described in the patient. *Chediak Higashi syndrome* - Chediak-Higashi syndrome is an autosomal recessive disorder characterized by **partial albinism**, recurrent pyogenic infections, and neurological abnormalities, due to defective lysosomal trafficking. - This syndrome is not primarily associated with extreme photosensitivity leading to early skin cancers but rather with immunodeficiency and neurological issues.
Question 8: A 6-year-old child born to consanguinity has pallor and intolerance to sunlight. His urine was exposed to Wood's light. Probable diagnosis is:
- A. SLE
- B. Xeroderma pigmentosum
- C. Gunther disease (Correct Answer)
- D. Bloom syndrome
Explanation: ***Gunther disease*** - The combination of **pallor**, **intolerance to sunlight** (photosensitivity), **consanguinity**, and particularly the **red fluorescence of urine under Wood's light** (due to increased uroporphyrins and coproporphyrins) is highly characteristic of **congenital erythropoietic porphyria (CEP)**, also known as Gunther disease. - This is an **autosomal recessive** disorder of heme synthesis, leading to accumulation of porphyrin precursors. Affected individuals often have **erythrodontia** (reddish-brown discoloration of teeth), severe **anemia**, and **hemolysis**, alongside marked photosensitivity. *SLE* - **Systemic lupus erythematosus (SLE)** can cause **photosensitivity** and **pallor (due to anemia)**, but it is an autoimmune disease, not an inborn error of metabolism. - It does not typically present with red fluorescent urine under Wood's light, which is a specific finding for porphyrias. *Xeroderma pigmentosum* - This is a rare **autosomal recessive** genetic disorder characterized by extreme **photosensitivity** and a high risk of skin cancers due to a defect in DNA repair mechanisms. - While it causes severe photosensitivity, it does not involve abnormalities in porphyrin metabolism or lead to red fluorescent urine. *Bloom syndrome* - **Bloom syndrome** is a rare **autosomal recessive** genetic disorder characterized by **photosensitivity**, **short stature**, a **distinctive facial appearance**, and an increased risk of cancer. - It does not involve porphyrin metabolism or result in red fluorescent urine under Wood's light.
Question 9: A 22-year-old female presents with dry papules in the seborrheic areas, especially in the summer. Her father also has a history of similar lesions. What is the most probable diagnosis?
- A. Pemphigus foliaceus
- B. Keratosis pilaris
- C. Darier's disease (Correct Answer)
- D. Seborrheic dermatitis
Explanation: ### Explanation **Correct Answer: C. Darier’s Disease** **Why it is correct:** Darier’s disease (Keratosis Follicularis) is an autosomal dominant genodermatosis caused by a mutation in the **ATP2A2 gene**, which encodes the **SERCA2 calcium pump**. This defect leads to a loss of cell-to-cell adhesion (acantholysis) and abnormal keratinization. * **Clinical Presentation:** It typically manifests as greasy, crusted, "dirty-looking" **malodorous papules** in a **seborrheic distribution** (chest, back, forehead, and scalp). * **Exacerbating Factors:** A classic hallmark is **photo-exacerbation**; lesions characteristically flare up during the **summer** due to heat, humidity, and UV exposure. The positive family history in this case further supports an inherited condition. **Why the other options are incorrect:** * **A. Pemphigus foliaceus:** While it involves acantholysis and affects seborrheic areas, it presents with superficial blisters and erosions rather than persistent keratotic papules, and it lacks a strong genetic/hereditary pattern. * **B. Keratosis pilaris:** Presents as "goose-flesh" papules on the extensor surfaces of arms and thighs. It is not typically found in seborrheic areas and does not flare specifically with summer heat. * **D. Seborrheic dermatitis:** Though it occurs in the same distribution, it presents as erythematous plaques with greasy yellow scales (dandruff-like) rather than discrete keratotic papules, and it usually improves or remains stable in summer rather than worsening. **High-Yield Clinical Pearls for NEET-PG:** * **Nail Findings:** Pathognomonic **"V-shaped" nicking** at the distal margin and longitudinal red/white bands. * **Mucosal Findings:** "Cobblestone" appearance of the oral mucosa. * **Histopathology:** Look for **"Corps ronds"** (in the stratum spinosum) and **"Grains"** (in the stratum corneum). * **Hand Findings:** Palmar pits and punctate keratosis.
Question 10: Spongiosis is a characteristic histological finding in which of the following conditions?
- A. Acute eczema (Correct Answer)
- B. Lichen planus
- C. Psoriasis
- D. Pemphigus
Explanation: **Explanation:** **Spongiosis** is the hallmark histological feature of **Acute Eczema**. It refers to **intercellular edema** within the epidermis. As fluid accumulates between keratinocytes, the desmosomes (intercellular bridges) become stretched and prominent, giving the epidermis a "sponge-like" appearance. If the fluid accumulation is severe, it leads to the formation of intraepidermal vesicles. **Analysis of Options:** * **A. Acute Eczema (Correct):** Spongiosis is the defining pathological process in all forms of eczematous dermatitis (atopic, contact, seborrheic). In the acute stage, spongiosis is maximal, often leading to clinical weeping and crusting. * **B. Lichen Planus:** Characterized by **interface dermatitis**. Key findings include "saw-tooth" rete ridges, basal cell degeneration (liquefaction necrosis), and Civatte bodies (apoptotic keratinocytes). * **C. Psoriasis:** Characterized by **regular acanthosis** (test-tube-like elongation of rete ridges), parakeratosis, Munro’s microabscesses (neutrophils in the stratum corneum), and Kogoj’s pustules. * **D. Pemphigus:** Characterized by **Acantholysis** (loss of intercellular connections leading to detached, rounded keratinocytes), not spongiosis. **High-Yield Clinical Pearls for NEET-PG:** * **Spongiotic Dermatitis** is a synonym for Eczema. * **Acanthosis** (thickening of the stratum spinosum) is seen in *Chronic* Eczema (Lichen Simplex Chronicus). * **Acantholysis vs. Spongiosis:** Acantholysis is the *primary failure* of adhesions (Pemphigus); Spongiosis is the *mechanical stretching* of adhesions due to fluid (Eczema). * **Munro’s Microabscess** is a classic "spotter" for Psoriasis on pathology slides.
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