Dermatitis and Eczema Practice Questions

Q: A 36-year-old farmer presented to the dermatology department with pruritic erythematous lesions on the arms, forearms, face, and retroauricular area after removing weeds in his farm. A diagnosis of phytodermatitis was made. What is the most likely plant responsible for this condition?

Parthenium hysterophorus. ### Explanation **Correct Option: A. Parthenium hysterophorus** The clinical presentation describes **Parthenium Dermatitis**, a common form of **Airborne Contact Dermatitis (ABCD)** in India. *Parthenium hysterophorus* (Congress grass/Gajar Ghas) contains **Sesquiterpene lactones**, which act as haptens. * **Mechanism:** It is a Type IV (Delayed) Hypersensitivity reaction. * **Distribution:** The "Airborne" pattern typically involves exposed areas like the face, neck, V-area of the chest, flexures (antecubital/popliteal fossae), and the **retroauricular area** (a classic diagnostic site that helps differentiate it from photodermatitis, which usually spares the retroauricular shadow). **Incorrect Options:** * **B. Urtica dioica (Stinging Nettle):** Causes **Contact Urticaria** (Type I Hypersensitivity/Immediate) via mechanical stings that release histamine and acetylcholine. It presents with immediate wheals rather than chronic eczematous lesions. * **C. Alstroemeria (Peruvian Lily):** A common cause of **Tulip finger** (allergic contact dermatitis) in florists, typically affecting the fingertips. * **D. Melaleuca alternifolia (Tea Tree Oil):** Known for causing allergic contact dermatitis due to oxidized terpenoids, but it is not associated with the specific airborne/weed-clearing pattern described. **Clinical Pearls for NEET-PG:** 1. **Diagnostic Test:** Patch testing with the **Sesquiterpene Lactone mix** or Parthenium leaf. 2. **Clinical Sign:** The **"Spare-part" sign** (sparing of the skin folds) is sometimes seen, though Parthenium is notorious for involving the folds in later stages. 3. **Differential Diagnosis:** Must be distinguished from **Chronic Actinic Dermatitis (CAD)**; however, Parthenium dermatitis involves the skin folds and retroauricular area, which are usually spared in CAD. 4. **Seasonality:** Often flares during the rainy season when the weed grows abundantly.

Q: Which of the following materials used to make jewelry will commonly cause contact dermatitis in sensitive individuals?

Nickel/chromium. **Explanation:** **1. Why Nickel/Chromium is Correct:** Nickel is the **most common cause of Allergic Contact Dermatitis (ACD)** worldwide. It is a **Type IV (delayed-type) hypersensitivity reaction** mediated by T-cells. In jewelry, nickel is frequently used as a base metal or alloy to provide hardness and luster. Chromium (often found in leather tanning and cement) is also a potent sensitizer. When these metals come into contact with sweat, metal ions are released, which act as **haptens**. These haptens bind to skin proteins to form a complete antigen, triggering an inflammatory response in sensitized individuals. **2. Why Other Options are Incorrect:** * **Sapphire:** This is a gemstone (corundum). Gemstones are chemically inert and do not release ions that penetrate the skin; therefore, they do not cause ACD. * **Silver:** Pure silver is generally non-allergenic. While some "sterling silver" contains copper or trace nickel that might cause a reaction, pure silver itself is considered safe. * **Gold:** Pure 24k gold is highly inert. While gold sodium thiosulfate is a known allergen, clinical dermatitis from gold jewelry is significantly rarer than nickel allergy. **3. High-Yield Clinical Pearls for NEET-PG:** * **Dimethylglyoxime Test:** A bedside chemical test used to detect the presence of nickel in jewelry (turns pink in the presence of nickel). * **Patch Test:** The gold standard investigation for diagnosing Allergic Contact Dermatitis. * **Common Sites:** Earlobes (earrings), wrists (watch straps), and infra-umbilical region (jeans buttons/belt buckles). * **Cross-reactivity:** Patients allergic to nickel often show cross-reactivity with **Cobalt**.

Q: A 55-year-old male, with uncontrolled diabetes mellitus and hypertension, developed severe airborne contact dermatitis. What is the most appropriate drug for his treatment?

Azathioprine. **Explanation:** The patient presents with **Airborne Contact Dermatitis (ABCD)**, most commonly caused by *Parthenium hysterophorus* in India. This condition often requires long-term immunosuppression as it is a chronic, relapsing Type IV hypersensitivity reaction. **Why Azathioprine is the Correct Answer:** Azathioprine is considered the **gold standard "steroid-sparing" agent** for chronic, recalcitrant ABCD. In this specific case, the patient has **uncontrolled diabetes mellitus and hypertension**. Azathioprine is preferred because it does not exacerbate glycemic levels or blood pressure, unlike systemic steroids or cyclosporine. Before starting, a Thiopurine Methyltransferase (TPMT) assay is ideally performed to prevent bone marrow toxicity. **Analysis of Incorrect Options:** * **Systemic Corticosteroids:** While effective for acute flares, they are contraindicated for long-term use in this patient due to his **uncontrolled diabetes** (causes hyperglycemia) and **hypertension** (causes fluid retention). * **Cyclosporine:** Although a potent immunosuppressant, it is avoided here because it is **nephrotoxic** and frequently causes or worsens **hypertension**, which is already uncontrolled in this patient. * **Thalidomide:** Primarily used in ENL (Leprosy) or actinic prurigo; it is not a first-line treatment for ABCD and carries a significant side-effect profile. **Clinical Pearls for NEET-PG:** * **Parthenium dermatitis** typically presents in an "airborne pattern" involving the eyelids, nasolabial folds, and retroauricular areas. * **Patch Test** is the gold standard for diagnosis. * **Steroid-sparing agents** (Azathioprine, Methotrexate) are essential for long-term management to avoid the "Cushingoid" side effects of chronic prednisone.

Q: Id reaction is associated with which of the following conditions?

Candidiasis. **Explanation:** **Id reaction**, also known as **Auto-eczematization**, is a secondary immunological response occurring in a site distant from the primary inflammatory or infectious focus. It is a **Type IV hypersensitivity reaction** triggered by circulating antigens (fungal, bacterial, or parasitic) rather than the spread of the organism itself. **Why Candidiasis is the correct answer:** Candidiasis is a classic cause of an Id reaction (specifically called a **Candidid**). When a primary infection (like vulvovaginal candidiasis or intertrigo) becomes acute or is treated aggressively, fungal antigens enter the bloodstream. This triggers a symmetrical, pruritic, papulovesicular eruption, typically on the hands or trunk. Other common triggers include dermatophytosis (Tinea pedis causing a 'Dermatophytid' on the hands) and stasis dermatitis. **Analysis of Incorrect Options:** * **Aphthous ulcer:** These are localized inflammatory ulcers of the oral mucosa. They are not associated with systemic hypersensitivity reactions like auto-eczematization. * **Herpetic stomatitis:** While viral infections can cause erythema multiforme, they are not typically associated with the classic "Id reaction" pattern seen in eczematous dermatology. * **Syphilis:** Secondary syphilis presents with a generalized rash, but this is due to the **direct hematogenous spread of *Treponema pallidum*** itself, not a sterile hypersensitivity reaction to distant antigens. **High-Yield Clinical Pearls for NEET-PG:** * **Key Feature:** The Id reaction is **sterile** (culture from the secondary site will be negative). * **Commonest trigger:** Tinea pedis (causing vesicles on the sides of fingers). * **Treatment:** The primary focus of infection must be treated for the Id reaction to resolve. Topical steroids are used for symptomatic relief of the secondary rash. * **Other triggers:** *Mycobacterium tuberculosis* (Lichen scrofulosorum) and *Staphylococcus aureus*.

Q: A 25-year-old male presents with multiple erythematous annular plaques with peripheral collarette of scales arranged predominantly over the trunk. What is the most probable diagnosis?

Pityriasis rosea. **Explanation:** The clinical presentation of **Pityriasis Rosea (PR)** is classic in this scenario. PR is a self-limiting, inflammatory skin disease, likely viral in origin (HHV-6 or HHV-7). The hallmark lesion is an **erythematous annular plaque** with a characteristic **"collarette of scales"**—where the scale is attached at the periphery and free towards the center. These lesions typically follow the lines of cleavage (Langer’s lines), creating a **"Christmas Tree" distribution** on the trunk. **Why the other options are incorrect:** * **Pityriasis versicolor:** Presents as hypo- or hyperpigmented macules with fine, "branny" (furfuraceous) scales, usually caused by *Malassezia* species. It lacks the inflammatory annular morphology and collarette scaling. * **Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing," and orange-red palmoplantar keratoderma. It does not typically present with isolated annular plaques and collarette scales. * **Pityriasis lichenoides chronica (PLC):** Presents with asymptomatic, brownish-pink papules with a "frosted glass" or "wafer-like" scale that can be lifted off entirely. It lacks the specific annular arrangement seen in PR. **NEET-PG High-Yield Pearls:** * **Herald Patch:** The first lesion to appear (larger, 2–10 cm) in 50–90% of cases, usually preceding the generalized eruption by 1–2 weeks. * **Hanging Curtain Sign:** On stretching the lesion, the scales fold inwards (characteristic of PR). * **Differential Diagnosis:** Always rule out **Secondary Syphilis**, which also involves the palms and soles (PR spares them). * **Treatment:** Reassurance; it is self-limiting (6–8 weeks). Severe cases may benefit from acyclovir or UVB therapy.

Q: A 5-year-old boy presents with a small hypopigmented scaly macule on his cheek. Some of his classmates also have similar lesions. What is the most probable diagnosis?

Pityriasis alba. **Explanation:** The correct diagnosis is **Pityriasis alba**. This is a common, benign condition primarily seen in children (3–16 years). It is considered a manifestation of **atopic dermatitis**. The classic presentation involves ill-defined, hypopigmented, slightly scaly macules or patches, most commonly located on the face (cheeks). The "epidemic" mention of classmates having similar lesions often points to shared environmental triggers like sun exposure or dry skin, rather than contagion. **Distinguishing the Options:** * **Pityriasis rosea:** Characterized by a "Herald patch" followed by a "Christmas tree" distribution of erythematous, scaly plaques on the trunk. It is not typically localized to a single facial macule. * **Pityriasis versicolor:** Caused by *Malassezia furfur*. While it causes hypopigmented scaly macules, it predominantly affects the chest and back (seborrheic areas) and is rare in young children. Diagnosis is confirmed by a "spaghetti and meatballs" appearance on KOH mount. * **Indeterminate leprosy:** Presents as a solitary, hypopigmented, non-scaly macule with **loss of sensation** and/or loss of hair. The presence of scales in the question points away from leprosy. **NEET-PG High-Yield Pearls:** * **Etiology:** Low-grade eczematous dermatitis; often associated with xerosis and sun exposure. * **Clinical Stages:** Starts as pink erythema $\rightarrow$ progresses to hypopigmented scaly patches $\rightarrow$ ends as smooth hypopigmented macules. * **Treatment:** Reassurance, emollients, and sun protection. * **Key Differentiator:** Unlike Vitiligo, Pityriasis alba has **ill-defined borders** and **fine scaling**.

Q: The Hanifin & Rajka diagnostic criteria are used for which condition?

Atopic dermatitis. **Explanation:** The **Hanifin and Rajka criteria** (established in 1980) are the traditional "gold standard" for diagnosing **Atopic Dermatitis (AD)**. Because there is no specific laboratory biomarker for AD, diagnosis relies on clinical morphology and history. To satisfy the criteria, a patient must meet at least **3 out of 4 Major features** and at least **3 out of 23 Minor features**: * **Major Criteria:** Pruritus (itching), Typical morphology and distribution (e.g., facial/extensor involvement in infants, flexural lichenification in adults), Chronic or chronically relapsing dermatitis, and Personal/family history of atopy (asthma, allergic rhinitis, AD). * **Minor Criteria:** Include xerosis, ichthyosis, elevated serum IgE, early age of onset, Dennie-Morgan infraorbital fold, keratosis pilaris, and white dermographism. **Why other options are incorrect:** * **Contact Dermatitis:** Diagnosed primarily via clinical history and **Patch Testing** (to identify Type IV hypersensitivity allergens). * **Urticaria:** Characterized by transient wheals and angioedema; diagnosis is clinical, often involving the **UAS7 (Urticaria Activity Score)** for severity. * **Erythroderma:** A clinical state (exfoliative dermatitis involving >90% body surface area) caused by various underlying conditions like psoriasis or drugs; it does not use these specific criteria. **High-Yield Clinical Pearls for NEET-PG:** * **UK Working Party Criteria:** A simplified version of Hanifin & Rajka often used in clinical trials (requires Itch + 3 or more minor criteria). * **Dennie-Morgan Fold:** An extra fold of skin under the lower eyelid, a classic minor sign of AD. * **Hertoghe’s Sign:** Thinning of the lateral third of the eyebrows (seen in AD and Hypothyroidism). * **Pathogenesis:** Often involves **Filaggrin (FLG) gene mutations**, leading to skin barrier defects.

Q: A 17-year-old female presents with a pruritic rash localized to the wrist. Papules and vesicles are noted in a bandlike pattern, with slight oozing from some lesions. What is the most likely cause of this rash?

Contact dermatitis. ### Explanation **Correct Answer: C. Contact Dermatitis** The clinical presentation of a pruritic rash localized to the wrist in a "bandlike pattern" is a classic description of **Allergic Contact Dermatitis (ACD)**. In this case, the pattern strongly suggests an exogenous trigger, most commonly **Nickel**, found in wristwatches, bracelets, or metallic straps. ACD is a **Type IV (Delayed) Hypersensitivity reaction**. The acute phase is characterized by erythematous papules, vesicles, and oozing (as seen here), while the chronic phase presents with lichenification and scaling. The most defining feature for NEET-PG is the **morphology conforming to the shape of the offending agent** (e.g., a band for a watch, a circle for a bindi, or a linear streak for Poison Ivy). **Why the other options are incorrect:** * **A & B (Herpes Simplex & Shingles):** While both can present with vesicles, they are typically painful or burning rather than primarily pruritic. Shingles (Herpes Zoster) follows a **dermatomal distribution**, not a circumferential bandlike pattern around a limb. * **D (Seborrheic Dermatitis):** This typically affects "seborrheic areas" rich in sebaceous glands, such as the scalp, eyebrows, and nasolabial folds. It presents with greasy, yellowish scales rather than oozing vesicles on the wrist. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Patch Testing (Readings taken at 48 and 72/96 hours). * **Common Allergens:** Nickel (most common worldwide), Potassium dichromate (cement/leather), Paraphenylenediamine (hair dye), and Neomycin (topical creams). * **Management:** Identification and avoidance of the allergen is the most crucial step. Topical corticosteroids are the first-line medical treatment.

Question 1

A 36-year-old farmer presented to the dermatology department with pruritic erythematous lesions on the arms, forearms, face, and retroauricular area after removing weeds in his farm. A diagnosis of phytodermatitis was made. What is the most likely plant responsible for this condition?

Accepted Answer

Parthenium hysterophorus

Answer

Urtica dioica

Answer

Alstroemeria

Answer

Melaleuca alternifolia

Question 2

Which of the following materials used to make jewelry will commonly cause contact dermatitis in sensitive individuals?

Accepted Answer

Nickel/chromium

Answer

Sapphire

Answer

Silver

Answer

Gold

Question 3

A patient presents with a rash. There is a family history of asthma. What is the most probable diagnosis?

Accepted Answer

Allergic contact dermatitis

Answer

Seborrheic dermatitis

Answer

Atopic dermatitis

Answer

Erysipelas

Question 4

A 55-year-old male, with uncontrolled diabetes mellitus and hypertension, developed severe airborne contact dermatitis. What is the most appropriate drug for his treatment?

Accepted Answer

Azathioprine

Answer

Systemic corticosteroids

Answer

Thalidomide

Answer

Cyclosporine

Question 5

Id reaction is associated with which of the following conditions?

Accepted Answer

Candidiasis

Answer

Aphthous ulcer

Answer

Herpetic stomatitis

Answer

Syphilis

Question 6

A 25-year-old male presents with multiple erythematous annular plaques with peripheral collarette of scales arranged predominantly over the trunk. What is the most probable diagnosis?

Accepted Answer

Pityriasis rosea

Answer

Pityriasis versicolor

Answer

Pityriasis rubra pilaris

Answer

Pityriasis lichenoides chronica

Question 7

A 5-year-old boy presents with a small hypopigmented scaly macule on his cheek. Some of his classmates also have similar lesions. What is the most probable diagnosis?

Accepted Answer

Pityriasis alba

Answer

Pityriasis rosea

Answer

Pityriasis versicolor

Answer

Indeterminate leprosy

Question 8

The Hanifin & Rajka diagnostic criteria are used for which condition?

Accepted Answer

Atopic dermatitis

Answer

Contact dermatitis

Answer

Urticaria

Answer

Erythroderma

Question 9

A 17-year-old female presents with a pruritic rash localized to the wrist. Papules and vesicles are noted in a bandlike pattern, with slight oozing from some lesions. What is the most likely cause of this rash?

Accepted Answer

Contact dermatitis

Answer

Herpes simplex

Answer

Shingles

Answer

Seborrheic dermatitis

Question 10

A 25-year-old male presents with recurrent episodes of flexural eczema, contact urticaria, recurrent skin infections, and severe abdominal cramps and diarrhea upon consuming seafood. What is the most likely diagnosis?

Accepted Answer

Atopic dermatitis

Answer

Seborrheic dermatitis

Answer

Airborne contact dermatitis

Answer

Nummular dermatitis

Dermatitis and Eczema — MCQs

Dermatitis and Eczema — MCQs

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