Contact Dermatitis: Allergic — MCQs
Dermatitis may be a clinical manifestation of deficiency states of all of the following nutrients except -
A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?
Steroids are used in the Rx of the following diseases EXCEPT:
Rakesh, a 7-year-old boy, presents with a 3-year history of itchy, excoriated papules on his forehead and exposed parts of his arms and legs. The condition is most severe during the rainy season and improves completely in winter. What is the most likely diagnosis?
A child presented with itchy plaques over the neck, the bilateral popliteal and cubital fossa. What could be the diagnosis?
Most common precipitant of contact dermatitis is?
Dermatological manifestation of which of the following diseases?
Pompholyx affects:
What condition is likely to be present in the child shown in the image, whose mother has asthma?
A 10-yr-old boy presented with painful boggy swelling of scalp, multiple sinuses with purulent discharge, easily pluckable hair, and lymph nodes enlarged in occipital region. Which one of the following would be most helpful for diagnostic evaluation?
Contact Dermatitis: Allergic Indian Medical PG Practice Questions and MCQs
Question 1: Dermatitis may be a clinical manifestation of deficiency states of all of the following nutrients except -
- A. Biotin
- B. Niacin
- C. Pyridoxine
- D. Thiamine (Correct Answer)
Explanation: ***Thiamine*** - A deficiency in **thiamine (vitamin B1)** primarily affects the nervous and cardiovascular systems, leading to conditions like **beriberi**, characterized by neuropathy, heart failure, and Wernicke-Korsakoff syndrome. - Dermatitis is **not a typical or direct clinical manifestation** of thiamine deficiency. *Biotin* - **Biotin (vitamin B7)** deficiency can cause **dermatitis**, often described as a scaly, erythematous rash around the eyes, nose, and mouth. - Hair loss (**alopecia**) and **neurological symptoms** are also associated with biotin deficiency. *Niacin* - **Niacin (vitamin B3)** deficiency leads to **pellagra**, classically presenting with the "3 Ds": **dermatitis**, **diarrhea**, and **dementia**. - The dermatitis in pellagra is typically symmetrical and photosensitive, affecting sun-exposed areas. *Pyridoxine* - **Pyridoxine (vitamin B6)** deficiency can result in **seborrheic dermatitis-like rash**, especially around the eyes, nose, and mouth. - Other symptoms include **glossitis**, **cheilosis**, and **neurological disturbances** like peripheral neuropathy.
Question 2: A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?
- A. Seborrheic dermatitis
- B. Atopic dermatitis (Correct Answer)
- C. Allergic contact dermatitis
- D. Erysipelas
Explanation: ***Atopic dermatitis*** - The presence of a rash in a child with a family history of **asthma** strongly suggests atopic dermatitis, as it is part of the **atopic triad** (eczema, asthma, allergic rhinitis). - Atopic dermatitis often presents with **erythematous, pruritic patches** and plaques, commonly affecting flexural areas like the antecubital and popliteal fossae, as well as the face and neck in younger children. *Seborrheic dermatitis* - This condition typically presents with **greasy, yellowish scales** on an erythematous base, often affecting areas rich in sebaceous glands such as the scalp, face (nasolabial folds), and chest. - While it can occur in infants, it does not have the strong association with a family history of asthma seen in atopic dermatitis. *Allergic contact dermatitis* - This rash results from an **exposure to an allergen**, leading to a localized, erythematous, and pruritic eruption, often with vesicles or bullae, at the site of contact. - The history does not provide information about a specific allergen exposure, and while it could produce a similar-looking rash, the family history of asthma points more strongly to atopic diathesis. *Erysipelas* - Erysipelas is a superficial skin infection, usually caused by *Streptococcus pyogenes*, presenting as a **well-demarcated, intensely erythematous, warm, and painful rash** with a raised border. - This is an **acute bacterial infection** and would typically be accompanied by systemic symptoms like fever and chills, which are not mentioned in the child's presentation.
Question 3: Steroids are used in the Rx of the following diseases EXCEPT:
- A. Pemphigus vulgaris
- B. Chronic fungal infection (Correct Answer)
- C. Erythema multiforme
- D. Contact dermatitis
Explanation: ***Chronic fungal infection*** - **Steroids are absolutely contraindicated** in **chronic fungal infections** as they **suppress cell-mediated immunity**, leading to worsening of the infection and potential dissemination. - Corticosteroids promote fungal growth and can convert a localized infection into a systemic, life-threatening condition. - This is the **clearest contraindication** among the options. *Pemphigus vulgaris* - **Pemphigus vulgaris** is an **autoimmune blistering disease** where **high-dose systemic steroids are the first-line treatment**. - Corticosteroids (1-2 mg/kg/day of prednisolone) are essential for controlling autoantibody production and preventing life-threatening complications. - **Steroids are clearly indicated**, not contraindicated. *Erythema multiforme* - **Erythema multiforme** is typically a **self-limiting condition** managed primarily with **supportive care** (antipyretics, antihistamines, topical care). - **Systemic steroids are generally NOT recommended** as standard treatment and their use remains **controversial**. - However, in very rare severe cases with extensive mucosal involvement, some clinicians may consider a short course, making this **not an absolute contraindication** like fungal infections. *Contact dermatitis* - **Contact dermatitis** is commonly treated with **topical corticosteroids** as first-line therapy to reduce inflammation and pruritus. - In severe, widespread cases, a short course of **oral steroids** may be prescribed. - **Steroids are clearly indicated** for this condition.
Question 4: Rakesh, a 7-year-old boy, presents with a 3-year history of itchy, excoriated papules on his forehead and exposed parts of his arms and legs. The condition is most severe during the rainy season and improves completely in winter. What is the most likely diagnosis?
- A. Insect bite hypersensitivity
- B. Scabies
- C. Atopic dermatitis (Correct Answer)
- D. Urticaria
Explanation: ***Atopic dermatitis*** - The **chronic itchy dermatitis** starting at age 4 and the presence of **excoriated papules** are consistent with atopic dermatitis, which is one of the most common chronic dermatoses in children. - While atopic dermatitis in school-age children typically affects **flexural areas** (antecubital and popliteal fossae), it can also involve the face and extensor surfaces, particularly as a continuation from earlier infantile patterns. - The **seasonal variation** can occur in atopic dermatitis due to changes in humidity, allergen exposure, and temperature, though the pattern of worsening in rainy season is somewhat atypical. - Given the chronic course and age of onset in early childhood with persistent itchy papules, atopic dermatitis remains the most likely diagnosis among the given options. *Insect bite hypersensitivity* - This would typically present with localized **urticarial papules** or **vesicles** at discrete bite sites, not a diffuse chronic condition lasting 3 years. - While insect bites can be seasonal and cause itchy excoriated papules, the **continuous 3-year duration** with consistent distribution patterns is not typical for bite reactions. *Scabies* - Scabies presents with intense itching (worse at night) and **pathognomonic burrows** in characteristic sites: finger webs, wrists, axillae, belt line, and genitalia. - The **distribution** described (forehead and exposed extremities) is not typical for scabies, nor would it show complete improvement seasonally without treatment. - Untreated scabies would not spontaneously resolve completely in winter. *Urticaria* - Urticaria manifests as **transient, migratory wheals** (hives) that typically resolve within 24 hours, even in chronic cases. - The description of persistent **excoriated papules** over 3 years is incompatible with urticaria, which is characterized by evanescent lesions, not fixed papules.
Question 5: A child presented with itchy plaques over the neck, the bilateral popliteal and cubital fossa. What could be the diagnosis?
- A. Dermatitis herpetiformis
- B. Psoriasis
- C. Pemphigus vegetans
- D. Atopic dermatitis (Correct Answer)
Explanation: **Atopic dermatitis** - The presentation of **itchy plaques** in the anatomical locations described (neck, bilateral popliteal fossa, and cubital fossa) is highly characteristic of **atopic dermatitis** in children. - Atopic dermatitis typically involves **flexural surfaces** in older children and adults, and is characterized by **intense pruritus**. *Dermatitis herpetiformis* - This condition presents with **extremely itchy, grouped vesicles and papules**, primarily on extensor surfaces, buttocks, and scalp. - It is strongly associated with **celiac disease** and is unlikely to present as plaques in flexural areas. *Psoriasis* - Psoriasis typically presents with **well-demarcated, erythematous plaques** covered with **silvery scales**, often on extensor surfaces (knees, elbows) and the scalp. - While it can occur in flexural areas (inverse psoriasis), **itching is usually less prominent** than in atopic dermatitis, and the characteristic scaling is usually present. *Pemphigus vegetans* - Pemphigus vegetans is a rare variant of pemphigus, characterized by **verrucous, vegetative lesions** and **bullae**, often in intertriginous areas. - This condition is a chronic autoimmune blistering disease and does not typically present as simple itchy plaques in a child.
Question 6: Most common precipitant of contact dermatitis is?
- A. Gold
- B. Silver
- C. Iron
- D. Nickel (Correct Answer)
Explanation: ***Nickel*** - **Nickel** is the most frequent cause of **allergic contact dermatitis**, commonly found in jewelry, belt buckles, and zippers. - Exposure leads to a **Type IV hypersensitivity reaction**, characterized by erythema, itching, and vesiculation. *Gold* - While gold can cause contact dermatitis, it is **far less common** than nickel allergy. - Reactions to gold are often seen with prolonged skin contact, such as with jewelry. *Silver* - **Silver** is a **rare cause** of allergic contact dermatitis. - Allergic reactions to silver are typically observed in individuals with extensive exposure, such as jewelers. *Iron* - **Iron** is **not a common precipitant** of contact dermatitis. - Allergic reactions to iron are exceedingly rare, as iron is an essential element found naturally in the body.
Question 7: 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 8: Pompholyx affects:
- A. Groin
- B. Scalp
- C. Trunk
- D. Palms and soles (Correct Answer)
Explanation: ***Palms and soles*** - **Pompholyx**, also known as **dyshidrotic eczema**, is characterized by recurrent outbreaks of **vesicles and bullae** predominantly on the palms and soles. - These lesions are typically very **itchy** and can cause significant discomfort. *Groin* - Conditions like **tinea cruris** (jock itch) or **intertrigo** commonly affect the groin, presenting with erythema and scaling rather than vesicles. - While eczema can occur in the groin, classical pompholyx has a predilection for the acral regions. *Scalp* - The scalp is more commonly affected by conditions such as **seborrheic dermatitis** or **psoriasis**, which manifest as scaling, redness, and flaking. - Vesicular eruptions are rare on the scalp unless due to specific conditions like herpes zoster. *Trunk* - The trunk is a common site for various dermatoses, including **atopic dermatitis**, **psoriasis**, or **pityriasis rosea**, but these typically present with different morphologic features (e.g., plaques, patches). - Pompholyx is specific to palms and soles and does not usually involve the trunk.
Question 9: What condition is likely to be present in the child shown in the image, whose mother has asthma?
- A. Atopic dermatitis (Correct Answer)
- B. SLE
- C. Erythema
- D. TEN
Explanation: ***Atopic dermatitis*** - The image shows an infant with **red, scaly, and irritated skin**, particularly on the cheeks and around the mouth, consistent with the characteristic presentation of **atopic dermatitis (eczema)** in infants. - Atopic dermatitis often occurs in individuals with a family history of **atopy**, which includes conditions like **asthma**, allergic rhinitis, and food allergies; a mother with asthma significantly increases the child's risk. *SLE* - **Systemic lupus erythematosus (SLE)** is a **chronic autoimmune inflammatory disease** that rarely presents in infancy with such prominent skin findings, especially without other systemic symptoms. - Skin manifestations of SLE typically include a **malar (butterfly) rash** or **discoid lesions**, which are different from the diffuse eczematous rash seen here. *Erythema* - **Erythema** simply refers to **redness of the skin** caused by inflammation or dilation of blood capillaries. - While the infant's skin is erythematous, erythema is a **symptom**, not a specific diagnosis, and does not fully describe the scaly, papular nature of the rash or the underlying condition. *TEN* - **Toxic epidermal necrolysis (TEN)** is a **severe, life-threatening skin condition** characterized by widespread epidermal detachment, forming large blisters and skin sloughing, often triggered by medications. - The skin lesions in the image do not show the extensive blistering and denudation characteristic of TEN, and a history of an asthmatic mother is not a risk factor for TEN.
Question 10: A 10-yr-old boy presented with painful boggy swelling of scalp, multiple sinuses with purulent discharge, easily pluckable hair, and lymph nodes enlarged in occipital region. Which one of the following would be most helpful for diagnostic evaluation?
- A. Biopsy
- B. KOH mount (Correct Answer)
- C. Bacterial culture
- D. Patch test
Explanation: ***KOH mount*** - A **potassium hydroxide (KOH) mount** of hair and scalp scrapings is the **most appropriate initial diagnostic test** for suspected **tinea capitis** with presentation suggestive of **kerion**. - The KOH mount allows for direct microscopic visualization of **fungal hyphae and spores** (endothrix or ectothrix pattern) within the hair shafts or skin scales, confirming a fungal infection rapidly. - It is **rapid, cost-effective, and non-invasive**, making it the preferred first-line diagnostic approach. - Note: While **fungal culture** is the gold standard for species identification and guides systemic antifungal therapy, KOH mount provides the quickest initial confirmation of fungal etiology. *Biopsy* - A **biopsy** may be considered for atypical presentations or if initial fungal studies are negative, but it is **more invasive** and not the **first-line diagnostic test** for suspected tinea capitis. - Histopathological examination can identify fungal elements and tissue reaction, but it is **not as rapid or straightforward** as a KOH mount for initial diagnosis. *Bacterial culture* - While **secondary bacterial infection** can occur with kerion (often *Staphylococcus aureus*), a bacterial culture primarily identifies bacterial pathogens and would **not confirm the underlying fungal etiology**. - The primary pathology here is **tinea capitis with kerion formation** (boggy swelling, purulent discharge, easily pluckable hair), which is fundamentally a severe inflammatory response to **dermatophyte infection**, not a primary bacterial infection. - Bacterial culture may be supplementary but does not address the primary diagnostic need. *Patch test* - A **patch test** is used to identify **allergic contact dermatitis** by applying specific allergens to the skin. - It is entirely **irrelevant for diagnosing an infectious condition** like tinea capitis with kerion.
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