Contact Dermatitis: Irritant — MCQs
Pruritus is a feature of which of the following conditions?
A person often feels that his hands are contaminated and is forced to wash his hands. Recently, he feels this repetitive, distressing thought of repetitive hand washing has begun affecting his performance. Which of the following is the best treatment option for this patient?
A patient comes to you with skin reactions after visiting the hair dresser. What will you do to confirm the diagnosis of contact dermatitis?
Characteristic of chronic eczema?
Dermatological manifestation of which of the following diseases?
Most common precipitant of contact dermatitis is?
Auspitz sign is seen in?
Treatment of choice for scabies in an infant aged 2-6 months is?
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 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?
Contact Dermatitis: Irritant Indian Medical PG Practice Questions and MCQs
Question 1: Pruritus is a feature of which of the following conditions?
- A. Pemphigus foliaceous
- B. Pemphigus vulgaris
- C. Bullous pemphigoid (Correct Answer)
- D. None of the options
Explanation: ***Bullous pemphigoid*** - **Pruritus**, often severe, is a common and early symptom of bullous pemphigoid, often preceding the appearance of skin lesions. - The disease involves autoantibodies against **hemidesmosomal proteins** (BPAG1, BPAG2), leading to subepidermal blister formation. *Pemphigus foliaceous* - This condition is characterized by **superficial blistering** and erosions, but **pruritus is typically mild or absent**. - Blisters form in the **granular layer of the epidermis** due to autoantibodies against desmoglein 1. *Pemphigus vulgaris* - Patients with pemphigus vulgaris present with **flaccid blisters and erosions**, mainly affecting the skin and mucous membranes, but **pruritus is not a prominent feature**. - The disease involves intraepidermal blistering caused by autoantibodies targeting **desmoglein 3 (and sometimes desmoglein 1)**. *None of the options* - This option is incorrect, as **pruritus is a characteristic symptom of bullous pemphigoid**.
Question 2: A person often feels that his hands are contaminated and is forced to wash his hands. Recently, he feels this repetitive, distressing thought of repetitive hand washing has begun affecting his performance. Which of the following is the best treatment option for this patient?
- A. Exposure and response prevention (Correct Answer)
- B. Systematic desensitization
- C. Dialectical Behavior Therapy (DBT)
- D. SSRI medication
Explanation: ***Exposure and Response Prevention (ERP)*** - This is the **gold standard psychotherapy** for **Obsessive-Compulsive Disorder (OCD)**, which is clearly indicated by the repetitive distressing thoughts (obsessions about contamination) and compulsive handwashing (compulsion). - ERP involves gradually exposing the patient to the feared situation (contamination) while preventing the compulsive ritual (handwashing), allowing habituation to anxiety. - **CBT with ERP is considered first-line treatment** alongside SSRIs, with ERP often preferred as initial **monotherapy** due to **durable effects** and **no medication side effects**. *Systematic Desensitization* - This therapy is primarily used to treat **phobias** and other **anxiety disorders** where a specific fear is present, rather than the obsession-compulsion cycle seen in OCD. - It involves gradual exposure with relaxation techniques, but **does not include response prevention**, which is crucial for breaking the compulsive cycle in OCD. *Dialectical Behavior Therapy (DBT)* - DBT is primarily developed for **Borderline Personality Disorder** and conditions with severe emotional dysregulation, self-harm, and interpersonal difficulties. - While it can help with emotional regulation, it **does not specifically target the obsession-compulsion cycle** that is the core pathology of OCD. *SSRI Medication* - **SSRIs are also first-line treatment for OCD** and are highly effective, particularly at higher doses than those used for depression. - However, when comparing initial treatment options, **ERP (psychotherapy) is often preferred** as monotherapy because it produces **sustained improvement** even after treatment ends, with lower relapse rates compared to medication discontinuation. - **Combination therapy (ERP + SSRI)** is typically reserved for moderate-to-severe OCD or when monotherapy is insufficient. - In this scenario asking for "best treatment option," ERP represents the most specific and effective **psychotherapeutic intervention** for OCD.
Question 3: A patient comes to you with skin reactions after visiting the hair dresser. What will you do to confirm the diagnosis of contact dermatitis?
- A. S IgE
- B. Allergy Test
- C. Patch Test (Correct Answer)
- D. VDRL
Explanation: ***Patch Test*** - A **patch test** is the gold standard for diagnosing **allergic contact dermatitis** by directly applying suspected allergens to the skin. - This test identifies specific substances that cause a delayed hypersensitivity reaction, which is characteristic of contact dermatitis. *S IgE* - **Serum IgE** levels are primarily indicative of **Type I hypersensitivity** reactions, such as allergic rhinitis or asthma. - Contact dermatitis is a **Type IV delayed hypersensitivity reaction**, not mediated by IgE antibodies. *Allergy Test* - The term "allergy test" is broad and can refer to various methods including skin prick tests, IgE blood tests, or patch tests. - Without specifying **patch testing**, other forms of allergy tests are less appropriate for diagnosing contact dermatitis, as they target different immune mechanisms. *VDRL* - **VDRL (Venereal Disease Research Laboratory)** test is used to screen for **syphilis**, a sexually transmitted infection. - It has no relevance to the diagnosis of contact dermatitis, which is an inflammatory skin condition caused by contact with an allergen or irritant.
Question 4: Characteristic of chronic eczema?
- A. Erythema
- B. Induration
- C. Lichenification (Correct Answer)
- D. Edema
Explanation: ***Lichenification*** - **Lichenification** is a hallmark of chronic eczema, characterized by thickening of the epidermis with exaggerated skin markings due to persistent rubbing or scratching. - This response reflects the long-term inflammatory and reparative processes in chronically affected skin. *Erythema* - **Erythema**, or redness, is a common finding in both acute and chronic inflammatory skin conditions, including acute eczema, but is not specifically characteristic of chronicity. - While present, it does not distinguish chronic from acute phases as definitively as other features. *Induration* - **Induration** refers to hardening or firmness of the skin, often due to inflammation or infection, and while it can be present in chronic eczema, it's a more general sign and not as specific as lichenification. - It might also suggest other conditions like cellulitis or deep tissue involvement. *Edema* - **Edema**, or swelling, is more prominent in the acute phase of eczema due to vasodilation and increased vascular permeability leading to fluid extravasation. - While some edema can persist, it's a less defining feature of chronic eczema compared to the epidermal changes observed in lichenification.
Question 5: 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 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: Auspitz sign is seen in?
- A. Psoriasis (Correct Answer)
- B. Vitiligo
- C. Contact dermatitis
- D. Lichen Planus
Explanation: ***Psoriasis*** - Auspitz sign refers to the appearance of **pinpoint bleeding** after the removal of psoriatic scales. - This phenomenon is caused by the thinning of the **epidermis** over the dermal papillae, making the superficial blood vessels more prone to rupture. *Vitiligo* - Vitiligo is characterized by **patches of depigmentation** due to the destruction of melanocytes. - It does not involve scaling or bleeding upon scratching. *Contact dermatitis* - Contact dermatitis is an **inflammatory skin reaction** caused by contact with an allergen or irritant, presenting as redness, itching, and sometimes vesicles. - While scratching can cause bleeding, it does not typically produce the specific **pinpoint bleeding** pattern seen with Auspitz sign. *Lichen Planus* - Lichen planus is an **inflammatory condition** affecting the skin, hair, nails, and mucous membranes, characterized by **pruritic, polygonal, purple papules**. - It does not present with scaling that reveals pinpoint bleeding when removed.
Question 8: Treatment of choice for scabies in an infant aged 2-6 months is?
- A. Ivermectin
- B. Crotomiton
- C. Permethrin (Correct Answer)
- D. BHC
Explanation: ***Permethrin*** - **Permethrin 5% cream** is the **treatment of choice for scabies** in infants aged 2 months and older, as it has a proven safety profile and high efficacy. - It is applied to the entire body from the neck down (including head and scalp in infants), left on for 8-14 hours, and then washed off; a second application is often recommended 7-14 days later. - **Note:** For infants younger than 2 months, precipitated sulfur (5-6% in petrolatum) is preferred as permethrin is not approved for this age group. *Ivermectin* - **Oral ivermectin** is generally not recommended for infants and children weighing less than 15 kg or under 5 years old due to potential neurotoxicity and lack of sufficient safety data in this age group. - It is typically reserved for severe or crusted scabies in older children and adults, or when topical treatments fail. *Crotomiton* - **Crotamiton (Eurax)** is less effective than permethrin and can cause skin irritation; it is not considered a first-line treatment for scabies in infants. - Its use is often limited to cases where permethrin is contraindicated or not tolerated, and it may require multiple applications over several days. *BHC* - **Lindane (benzene hexachloride)** is **not recommended for infants** due to its potential for neurotoxicity, including seizures, especially in those with compromised skin barriers or young age. - It has largely been replaced by safer and equally effective treatments like permethrin.
Question 9: 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 10: 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.
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