Dermatitis and Eczema Practice Questions

Q: A woman with diabetes mellitus presents with an asymptomatic skin lesion present for the past one year. On examination, there is a non-scaly, annular lesion as shown in the image. There is no itching or pain. What is the most likely diagnosis?

Granuloma annulare. ***Granuloma annulare*** - This condition is classically associated with **diabetes mellitus** and presents as **asymptomatic, non-scaly**, annular plaques with a smooth surface. - The lesions are typically characterized by a **ring of papules** with central clearing and are frequently found on the **dorsal surfaces of the hands** and feet. *Tinea corporis* - This is a **dermatophyte fungal infection** that typically presents with **scaly, erythematous borders** and active peripheral inflammation. - Unlike the lesion in the prompt, tinea corporis is usually **pruritic** and requires antifungal treatment, making it less likely in an asymptomatic, non-scaly presentation. *Annular lichen planus* - While lichen planus can present with annular plaques, the lesions are typically **violaceous, flat-topped papules** with characteristic **Wickham striae** (white lacy lines). - Lichen planus lesions are notoriously **pruritic** and often affect flexural surfaces, distinguishing them from the asymptomatic, non-scaly nature of granuloma annulare. *Annular psoriasis* - Psoriasis of the annular type, like other forms of psoriasis, typically presents with **thick, silvery-white micaceous scales**. - The condition is often **symptomatic** (itching) and does not show the smooth, non-scaly border characteristic of the patient's lesion.

Q: A child presents with severe itching involving the extensor surface, especially at night . There is a positive family history of asthma in father. On examination, the child has dry, itchy skin with eczematous lesions. What is the most likely diagnosis?

Atopic dermatitis. ***Atopic dermatitis*** - This condition, often part of the **atopic triad (asthma, allergic rhinitis, atopic dermatitis)**, is strongly supported by the patient's positive family history of **atopy**. - Intense **pruritus** is the hallmark symptom, and chronic scratching leads to the observed eczematous lesions, which can present on **extensor surfaces** in infants/young children before shifting to flexural areas later in childhood. *Scabies* - Caused by the mite **Sarcoptes scabiei**, it presents with **nocturnal pruritus** but typically involves **interdigital spaces**, wrists, and axillae. - Look for **burrows** on examination; while a family history is often positive due to contagion, the clinical distribution and morphology here favor eczema. *Cradle cap (Seborrheic dermatitis)* - Typically presents in infancy as **greasy, yellow scales** on the scalp and face, rather than generalized eczematous skin. - It is not associated with severe **pruritus** or a personal/family history of **atopic diseases** like asthma. *Contact dermatitis* - Requires a history of exposure to an **irritant** or **allergen**, such as soaps, nickel, or plants, which is not mentioned. - The distribution is usually localized to the **area of contact** rather than the generalized pattern seen in atopic dermatitis.

Q: A 48-year-old woman with a 10-year history of rheumatoid arthritis (anti-CCP positive) presents with a rapidly progressive, extremely painful ulcer over the anterior aspect of the shin. The lesion began as a pustule and progressed to a deep ulcer with anecrotic black eschar and violaceous undermined margins. There is no history of trauma or diabetes. What is the most likely diagnosis?

Pyoderma gangrenosum. ***Pyoderma gangrenosum*** - The presence of a rapidly progressive, painful ulcer with **violaceous, undermined, and irregular margins** is the classic presentation of this condition. - It is strongly associated with underlying systemic inflammatory disorders, particularly **rheumatoid arthritis** and **inflammatory bowel disease**. *Cutaneous TB* - This usually presents as a slow-growing plaque or nodule, often manifesting as **lupus vulgaris** or **scrofuloderma**, rather than a rapid, necrotizing ulcer. - Diagnosis typically requires biopsy showing **caseating granulomas** and demonstration of mycobacteria, which is inconsistent with this acute clinical picture. *Ecthmya gangrenosum* - Primarily caused by **Pseudomonas aeruginosa** sepsis, typically affecting immunocompromised patients, and lacks the strong association with RA. - The lesions usually start as erythematous macules that evolve into bullae and then ulcers with a **central black eschar**, but are typically linked to systemic bacterial infection rather than chronic autoimmune disease. *Necrotising fasciitis* - A life-threatening surgical emergency characterized by **crepitus**, rapid spread along fascial planes, and systemic signs of **sepsis**. - It does not typically present as a localized, chronic-associated ulcer with distinctively **undermined borders** in an ambulatory patient.

Q: In infancy, atopic dermatitis typically spares which of the following areas?

Diaper area. **Explanation:** Atopic Dermatitis (AD) is a chronic, pruritic inflammatory skin disease that follows a characteristic age-dependent distribution. In **infancy** (birth to 2 years), the correct answer is the **Diaper area (Option D)**. **Why the Diaper Area is Spared:** The diaper area is typically spared in infantile AD because the high humidity and moisture trapped by the diaper prevent skin dehydration (transepidermal water loss). Since xerosis (dryness) is a primary trigger for AD, the "occlusive" effect of the diaper protects this specific region. If a rash is present in the diaper area, clinicians should consider Seborrheic Dermatitis or Irritant Diaper Dermatitis instead. **Analysis of Incorrect Options:** * **A. Extensor surfaces:** These are the classic sites for AD in infants. As babies begin to crawl, the friction on the knees and elbows triggers the "itch-scratch cycle." * **B. Forehead & C. Scalp:** The face (especially the cheeks and forehead) and the scalp are often the first sites involved in infancy. The lesions are typically acute, presenting as erythematous, edematous, and sometimes weeping plaques. **High-Yield Clinical Pearls for NEET-PG:** * **Evolution of Sites:** * **Infancy:** Face, scalp, and extensors (spares diaper area). * **Childhood/Adulthood:** Flexural surfaces (antecubital and popliteal fossae), neck, and wrists. * **Hertoghe’s Sign:** Thinning of the lateral third of the eyebrows (due to chronic rubbing). * **Dennie-Morgan Fold:** An extra fold of skin under the lower eyelid. * **Filaggrin (FLG) Mutation:** The most common genetic defect associated with skin barrier dysfunction in AD.

Q: A 45-year-old farmer presents with a 3-year history of itchy, erythematous papular lesions on the face, neck, 'V' area of the chest, and the dorsum of the hands and forearms. The lesions are more severe in the summer and improve significantly in the winter. What is the most appropriate diagnostic test for this condition?

Patch test. ### Explanation **Diagnosis: Parthenium Dermatitis (Airborne Contact Dermatitis)** The clinical presentation of itchy, erythematous papules in a "photo-distributed" pattern (face, neck, 'V' area of chest, and dorsum of hands/forearms) in a farmer, with seasonal exacerbation in summer, is classic for **Parthenium Dermatitis**. This is a type of **Airborne Contact Dermatitis (ABCD)** caused by the weed *Parthenium hysterophorus*. **1. Why Patch Test is the Correct Answer:** Parthenium dermatitis is a **Type IV (Delayed-type) Hypersensitivity reaction**. The gold standard for diagnosing Type IV hypersensitivity is the **Patch Test**. It identifies the specific allergen (usually the sesquiterpene lactone in Parthenium) responsible for the T-cell mediated allergic response. **2. Why Other Options are Incorrect:** * **Skin Biopsy:** While it may show features of eczematous dermatitis (spongiosis), it is non-specific and cannot identify the causative allergen. * **Intradermal Prick Test:** This is used to diagnose **Type I (Immediate) Hypersensitivity** (e.g., asthma, allergic rhinitis). It is not used for contact dermatitis. * **Estimation of IgE levels:** IgE is a marker for Type I hypersensitivity and atopic conditions. It has no diagnostic value in Type IV hypersensitivity reactions like ABCD. **Clinical Pearls for NEET-PG:** * **Distribution:** Unlike true photodermatitis, ABCD often involves the **upper eyelids, nasolabial folds, and retroauricular areas** (the "shadow regions"), as pollen/dust can settle there. * **Common Allergen:** In India, *Parthenium hysterophorus* (Congress grass) is the most common cause. * **Management:** Avoidance of the allergen is key. Topical steroids and sun protection are used for symptomatic relief. In chronic cases, azathioprine may be used as a steroid-sparing agent.

Q: Contact dermatitis is a type of:

Type-IV hypersensitivity. **Explanation:** **Correct Answer: D. Type-IV hypersensitivity** Contact dermatitis is a classic example of **Type-IV (Delayed-type) hypersensitivity**. Unlike other types, this is **cell-mediated** rather than antibody-mediated. When a hapten (e.g., nickel, poison ivy, or chemicals in cosmetics) penetrates the skin, it binds to skin proteins to become antigenic. These are processed by Langerhans cells and presented to **T-helper 1 (Th1) cells**. Upon re-exposure, sensitized T-cells release cytokines (IFN-γ, IL-2), recruiting macrophages that cause epidermal damage and vesicle formation. The reaction typically peaks **48–72 hours** after exposure. **Why other options are incorrect:** * **Type-I (Immediate):** Mediated by **IgE** and mast cell degranulation (e.g., Anaphylaxis, Urticaria). It occurs within minutes. * **Type-II (Cytotoxic):** Mediated by **IgG or IgM** against antigens on cell surfaces (e.g., Rh incompatibility, Myasthenia Gravis). * **Type-III (Immune-complex):** Caused by deposition of **antigen-antibody complexes** in tissues (e.g., SLE, Serum sickness, Arthus reaction). **NEET-PG High-Yield Pearls:** * **Patch Test:** The gold standard diagnostic tool for identifying the allergen in contact dermatitis (read at 48 and 72 hours). * **Key Mediators:** CD4+ T-cells (Th1) and Macrophages. * **Other Type-IV Examples:** Mantoux test (Tuberculin reaction), Lepromin test, Graft rejection (acute/chronic), and Granuloma formation (e.g., Sarcoidosis). * **Mnemonic:** **ACID** (Type **A**naphlyactic, **C**ytotoxic, **I**mmune-complex, **D**elayed).

Q: Commonest site of Atopic dermatitis is:

Ante-cubital fossa. **Explanation:** Atopic Dermatitis (AD) is a chronic, relapsing inflammatory skin condition characterized by intense pruritus and a characteristic age-dependent distribution. The correct answer is **Ante-cubital fossa** because it represents the classic **flexural involvement** seen in the childhood and adult phases of the disease. **Why Ante-cubital fossa is correct:** In patients beyond infancy (children, adolescents, and adults), the morphology of AD shifts from exudative lesions to lichenified plaques. These lesions characteristically involve the flexural surfaces, specifically the **ante-cubital** and **popliteal fossae**, the neck, and the wrists. This is a hallmark diagnostic feature in the Hanifin and Rajka criteria. **Why other options are incorrect:** * **Scalp:** While the scalp can be involved in infantile AD (often confused with seborrheic dermatitis), it is not the "commonest" or most characteristic site across the broader age spectrum. * **Elbow:** The **extensor** aspect of the elbow is typically involved in **psoriasis**. In AD, extensor involvement is usually limited to the infantile phase; as the child grows, the disease "moves" to the flexures. * **Trunk:** While the trunk can be affected in severe or generalized cases (erythroderma), it is rarely the primary or most common site of localization compared to the limbs. **High-Yield Clinical Pearls for NEET-PG:** * **Infantile Phase (<2 years):** Characteristically involves the **face (cheeks)** and extensor surfaces. The diaper area is usually spared. * **Childhood/Adult Phase:** Characteristically involves **flexures** (ante-cubital/popliteal). * **Dennie-Morgan fold:** An extra fold of skin under the lower eyelid, a classic sign of atopy. * **Filaggrin (FLG) mutation:** The most common genetic defect associated with skin barrier dysfunction in AD. * **Serum IgE:** Usually elevated in the "extrinsic" type of Atopic Dermatitis.

Q: Which of the following monoclonal antibodies is used in the treatment of atopic dermatitis?

Dupilumab. **Explanation:** **1. Why Dupilumab is Correct:** Dupilumab is a fully human monoclonal antibody that targets the **interleukin-4 receptor alpha (IL-4Rα) subunit**. By binding to this subunit, it inhibits the signaling of both **IL-4 and IL-13**. These cytokines are the key drivers of **Type 2 (Th2) inflammation**, which is the primary pathophysiological mechanism in atopic dermatitis. It is currently the first-line systemic biologic approved for moderate-to-severe atopic dermatitis unresponsive to topical therapies. **2. Why the Other Options are Incorrect:** * **Ipilimumab:** A checkpoint inhibitor that targets **CTLA-4**. It is used in the treatment of advanced melanoma and renal cell carcinoma. * **Durvalumab:** A checkpoint inhibitor that targets **PD-L1**. It is primarily used in the treatment of non-small cell lung cancer (NSCLC) and bladder cancer. * **Reslizumab:** An interleukin-5 (**IL-5**) antagonist. It is used as add-on maintenance treatment for severe eosinophilic asthma, not atopic dermatitis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Dual inhibitor of IL-4 and IL-13. * **Common Side Effect:** The most characteristic side effect of Dupilumab is **allergic conjunctivitis** and blepharitis. * **Other Indications:** It is also FDA-approved for moderate-to-severe asthma (eosinophilic phenotype) and chronic rhinosinusitis with nasal polyposis. * **Memory Aid:** "Dupi" stops the "D"ermatitis by blocking the "4" and "13" (IL-4/13).

Question 1

A woman with diabetes mellitus presents with an asymptomatic skin lesion present for the past one year. On examination, there is a non-scaly, annular lesion as shown in the image. There is no itching or pain. What is the most likely diagnosis?

Accepted Answer

Granuloma annulare

Answer

Tinea corporis

Answer

Annular lichen planus

Answer

Annular psoriasis

Question 2

A child presents with severe itching involving the extensor surface, especially at night . There is a positive family history of asthma in father. On examination, the child has dry, itchy skin with eczematous lesions. What is the most likely diagnosis?

Accepted Answer

Atopic dermatitis

Answer

Scabies

Answer

Cradle cap (Seborrheic dermatitis)

Answer

Contact dermatitis

Question 3

A 48-year-old woman with a 10-year history of rheumatoid arthritis (anti-CCP positive) presents with a rapidly progressive, extremely painful ulcer over the anterior aspect of the shin. The lesion began as a pustule and progressed to a deep ulcer with anecrotic black eschar and violaceous undermined margins. There is no history of trauma or diabetes. What is the most likely diagnosis?

Accepted Answer

Pyoderma gangrenosum

Answer

Cutaneous TB

Answer

Ecthmya gangrenosum

Answer

Necrotising fasciitis

Question 4

How does chronic cumulative irritant contact dermatitis differ pathophysiologically from acute irritant contact dermatitis?

Accepted Answer

It results from repeated sub-threshold exposures causing cumulative damage

Answer

It involves immunologic memory cells

Answer

It shows immediate vesiculation

Answer

It is mediated by IgE antibodies

Question 5

In infancy, atopic dermatitis typically spares which of the following areas?

Accepted Answer

Diaper area

Answer

Extensor surfaces

Answer

Forehead

Answer

Scalp

Question 6

A 45-year-old farmer presents with a 3-year history of itchy, erythematous papular lesions on the face, neck, 'V' area of the chest, and the dorsum of the hands and forearms. The lesions are more severe in the summer and improve significantly in the winter. What is the most appropriate diagnostic test for this condition?

Accepted Answer

Patch test

Answer

Skin biopsy

Answer

Intradermal prick test

Answer

Estimation of IgE levels in blood

Question 7

A 28-year-old G1P0 at 32 weeks gestation presents with itchy, erythematous papules on the extensor surfaces and trunk. There is no history of fever or use of new creams or lotions. What is the first-line treatment for this condition?

Accepted Answer

Topical steroids and oral antihistamines

Answer

Antibiotic therapy

Answer

Antivirals and termination of pregnancy

Answer

Oral steroids

Question 8

Contact dermatitis is a type of:

Accepted Answer

Type-IV hypersensitivity

Answer

Type-I hypersensitivity

Answer

Type-II hypersensitivity

Answer

Type-III hypersensitivity

Question 9

Commonest site of Atopic dermatitis is:

Accepted Answer

Ante-cubital fossa

Answer

Scalp

Answer

Elbow

Answer

Trunk

Question 10

Which of the following monoclonal antibodies is used in the treatment of atopic dermatitis?

Accepted Answer

Dupilumab

Answer

Ipilimumab

Answer

Durvalumab

Answer

Reslizumab

Dermatitis and Eczema — MCQs

Dermatitis and Eczema — MCQs

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