Dermatitis and Eczema Practice Questions

Q: What is the most likely cause of these skin changes?

Chronic venous stasis. ***Chronic venous stasis*** - The image shows **hyperpigmentation**, **edema**, and **varicose veins** on the lower leg, which are classic features of **stasis dermatitis**. - Chronic venous insufficiency leads to **hemosiderin deposition** causing brown discoloration and **chronic inflammation** in the lower extremities. *Asteatotic eczema* - Typically presents with **dry, scaly, cracked skin** resembling a "crazy paving" pattern, not the hyperpigmented changes seen here. - Usually affects elderly patients and involves **xerosis** (dry skin) rather than **venous congestion** signs. *Necrobiosis lipoidica* - Characterized by **yellow-brown plaques** with **waxy appearance** and **telangiectasias**, typically on the shins. - Strongly associated with **diabetes mellitus** and shows **central atrophy** with raised borders, unlike the diffuse changes shown. *Pretibial myxedema* - Presents as **non-pitting, waxy, orange-peel textured plaques** on the anterior shins in **hyperthyroid patients**. - Associated with **Graves' disease** and lacks the **venous congestion** and **hemosiderin staining** visible in this case.

Q: All of the following are exogenous eczema except?

Stasis dermatitis. ### Explanation Eczema (Dermatitis) is broadly classified into two categories based on the source of the trigger: **Exogenous** (external factors) and **Endogenous** (internal/constitutional factors). **Why Stasis Dermatitis is the Correct Answer:** Stasis dermatitis is an **endogenous** eczema. It occurs due to chronic venous insufficiency and venous hypertension, typically in the lower limbs. The underlying pathophysiology involves the failure of venous valves, leading to blood pooling, increased hydrostatic pressure, and subsequent leakage of fibrin and inflammatory mediators into the dermis. Since the cause is internal (vascular dysfunction), it is not considered exogenous. **Analysis of Incorrect Options (Exogenous Eczemas):** * **Irritant Contact Dermatitis:** Caused by direct cytotoxic damage to the skin by external chemical or physical agents (e.g., detergents, acids). * **Infective Dermatitis:** Triggered by an external microbial burden (e.g., *Staphylococcus aureus*) or its metabolic products, often complicating a pre-existing skin condition. * **Photodermatitis:** An exogenous reaction where skin inflammation is triggered by the interaction between UV radiation and an external substance (phototoxic/photoallergic). **High-Yield Clinical Pearls for NEET-PG:** * **Stasis Dermatitis:** Often presents with "inverted champagne bottle" appearance (lipodermatosclerosis) and is a precursor to venous ulcers (medial malleolus). * **Endogenous Eczemas:** Include Atopic dermatitis, Seborrheic dermatitis, Pompholyx (Dysidrotic), and Discoid (Nummular) eczema. * **Patch Test:** The gold standard investigation for Allergic Contact Dermatitis (Exogenous), whereas it is usually negative in endogenous types. * **Asteatotic Eczema:** Also known as *Eczema Craquelé*, it is an endogenous eczema common in the elderly due to decreased skin lipids.

Q: All are skin findings in atopic dermatitis, EXCEPT:

Black dermatographism. **Explanation:** Atopic Dermatitis (AD) is a chronic inflammatory skin condition characterized by specific major and minor diagnostic criteria (Hanifin and Rajka criteria). **Why Option D is the Correct Answer:** **Black dermatographism** is not a feature of atopic dermatitis. It is a physical phenomenon where skin contact with certain metals (like gold or silver) results in a black/greenish streak due to the abrasion of metal particles by powders or makeup on the skin. In contrast, Atopic Dermatitis is associated with **White dermatographism**. When the skin of an atopic patient is stroked with a blunt object, the initial red line is rapidly replaced by a persistent white line (due to abnormal capillary vasoconstriction), which is a characteristic minor criterion. **Analysis of Incorrect Options:** * **A. Facial Pallor:** This is a common finding in AD, often presenting as infraorbital darkening (Dennie-Morgan folds) contrasted with a pale mid-face, caused by increased sympathetic tone and vasoconstriction. * **B. Pityriasis Alba:** These are hypopigmented, slightly scaly patches commonly found on the face and arms of children with an atopic diathesis. * **C. Keratosis Pilaris:** Characterized by "chicken skin" appearance (keratotic follicular plugs) on the extensor surfaces of the arms and thighs, it is a very frequent associated finding in atopic individuals. **High-Yield Clinical Pearls for NEET-PG:** * **Filaggrin (FLG) mutation:** The most common genetic defect leading to skin barrier dysfunction in AD. * **Dennie-Morgan Fold:** An extra fold of skin under the lower eyelid, a classic sign of AD. * **Hertoghe’s Sign:** Thinning or loss of the outer third of the eyebrows due to chronic rubbing/itching. * **Serum IgE:** Usually elevated in extrinsic AD.

Q: A 5-year-old boy with a history of atopy presents with multiple asymptomatic oval and circular faintly hypopigmented macules with fine scaling on his face. What is he suffering from?

Pityriasis alba. ### Explanation **Pityriasis alba** is the correct diagnosis based on the classic clinical triad: **young age (children), history of atopy, and characteristic morphology** (faintly hypopigmented macules with fine scaling on the face). #### Why Pityriasis Alba? It is considered a minor manifestation of **atopic dermatitis**. The lesions typically progress through three stages: an initial faint pink erythema, followed by the characteristic hypopigmented macules with **fine, branny scaling** (pityriasis means "scaly"), and finally smooth hypopigmentation. It is most common on the cheeks and is often more noticeable after sun exposure as the surrounding skin tans. #### Why other options are incorrect: * **Acrofacial Vitiligo:** Presents as **depigmented** (chalky white) macules, not hypopigmented. It has sharp margins, lacks scaling, and typically involves the periorificial areas and fingertips. * **Pityriasis Versicolor:** Caused by *Malassezia* furfur. While it presents with scaling and hypopigmentation, it is rare in young children and typically involves the "seborrheic areas" like the chest and back rather than the face. * **Indeterminate Leprosy:** Presents as a solitary or few hypopigmented macules. However, it usually lacks scaling, and the hallmark is a **loss of sensation** or hair within the patch, which is absent here. #### NEET-PG High-Yield Pearls: * **Histopathology:** Shows hyperkeratosis, parakeratosis, and decreased melanin in the basal layer. * **Treatment:** Reassurance, sun protection, and emollients. Low-potency topical steroids or calcineurin inhibitors (Tacrolimus) may be used for inflammation. * **Differential Diagnosis Tip:** If a hypopigmented patch on a child's face is **anesthetic**, think Leprosy; if it is **scaly and atopic**, think Pityriasis alba; if it is **completely white**, think Vitiligo.

Q: What is the best initial treatment for acute contact dermatitis?

Moist compress. **Explanation:** The management of dermatitis is guided by the clinical stage of the lesion (Acute, Subacute, or Chronic). **1. Why Moist Compresses are correct:** Acute contact dermatitis is characterized by **"wet"** features: erythema, edema, vesiculation, and oozing. The fundamental dermatological principle is **"If it is wet, dry it."** Moist compresses (using saline or Burow’s solution) facilitate evaporation, which cools the inflammation, constricts blood vessels to reduce oozing, and helps debride crusts. This "drying out" effect is essential before transitioning to topical medications. **2. Why other options are incorrect:** * **Topical Ointments (B):** These are greasy and occlusive. Applying an ointment to an acute, oozing lesion "traps" the heat and moisture, potentially leading to maceration and secondary infection (folliculitis). Ointments are the gold standard for **chronic** (dry/lichenified) dermatitis. * **Topical Creams (A):** While less occlusive than ointments, creams are generally preferred for **subacute** dermatitis. In the hyper-acute stage, even creams may not be as effective as compresses for managing active discharge. * **Emulsion Vehicles (C):** These are mixtures of oil and water (like lotions). While soothing, they lack the potent evaporative and debriding power required for the initial management of acute, weeping vesicles. **Clinical Pearls for NEET-PG:** * **Rule of Thumb:** Acute = Wet (use Soaks/Compresses); Chronic = Dry (use Ointments). * **Burow’s Solution:** A 1:40 solution of aluminum acetate, frequently used for medicated compresses. * **Potassium Permanganate (KMnO₄):** Used in 1:10,000 dilution for its astringent and antiseptic properties in weeping eczema. * **Steroids:** While topical steroids are the mainstay of treatment, they are most effective once the "weeping" phase has been controlled by initial compresses.

Q: Which of the following causes allergic contact dermatitis through air?

Parthenium. **Explanation:** **Parthenium hysterophorus** (Congress grass) is the most common cause of **Airborne Contact Dermatitis (ABCD)** in India. The underlying mechanism is a **Type IV (Delayed) Hypersensitivity reaction** to the sesquiterpene lactones present in the plant's pollen and trichomes. These allergens become airborne and settle on exposed areas of the skin, typically affecting the face (eyelids, nasolabial folds), neck, retroauricular area, and flexures. **Analysis of Options:** * **Parthenium (Correct):** It classically presents as a "patterned" dermatitis on exposed areas. Over time, it can progress to **Exfoliative Dermatitis** or a **Photosensitive** pattern (Chronic Actinic Dermatitis). * **House dust mite:** While a common trigger for *Atopic Dermatitis* (via inhalation or direct contact), it is not a primary cause of classic allergic contact dermatitis through the air. * **Nickel:** This is the most common cause of **Contact Dermatitis** worldwide, but it requires **direct skin contact** (e.g., jewelry, belt buckles, watches). It is not airborne. * **Detergents:** These typically cause **Irritant Contact Dermatitis** (not allergic) through direct, repetitive handling, often leading to "housewife’s hand eczema." **Clinical Pearls for NEET-PG:** * **Diagnostic Test:** The gold standard for Parthenium allergy is the **Patch Test**. * **Clinical Sign:** The **"Window Sign"** (sparing of the skin folds behind the ears or under the chin) helps differentiate ABCD from photodermatitis. * **Treatment:** Avoidance is key; however, severe cases may require systemic immunosuppressants like Azathioprine.

Q: Perioral pallor and Dennie's lines are seen in which condition?

Atopic dermatitis. **Explanation:** The correct answer is **Atopic Dermatitis (AD)**. This condition is a chronic, relapsing inflammatory skin disease characterized by intense pruritus and a specific distribution of lesions. Diagnosis is primarily clinical, based on the **Hanifin and Rajka criteria**, which include several "minor" clinical signs. * **Dennie-Morgan Lines:** These are characteristic infraorbital folds or wrinkles caused by chronic edema and inflammation of the lower eyelids. * **Perioral Pallor:** This refers to a pale appearance around the mouth, often contrasting with the erythematous, eczematous patches on the cheeks (common in the infantile phase). **Analysis of Incorrect Options:** * **Chronic actinic dermatitis:** An immunologically mediated photosensitivity disorder. It presents as eczematous lesions in sun-exposed areas, not typically associated with these specific infraorbital or perioral signs. * **Blood dyscrasias:** These usually present with purpura, petechiae, or mucosal bleeding rather than eczematous features or Dennie-Morgan lines. * **Perioral contact dermatitis:** While it involves the perioral area, it typically presents with erythema, scaling, and papules *around* the mouth, often sparing a thin rim of skin near the vermilion border. It does not feature Dennie-Morgan lines. **High-Yield Clinical Pearls for NEET-PG:** * **Hertoghe’s sign:** Thinning or loss of the lateral third of the eyebrows (seen in AD and Hypothyroidism). * **Pityriasis alba:** Hypopigmented, slightly scaly patches on the face; a minor criterion for AD. * **Hyperlinear palms:** Increased skin markings on the palms, frequently associated with Ichthyosis vulgaris and AD. * **Dermatographism:** Patients with AD often show **white dermatographism** (vasoconstriction) instead of the typical red wheal.

Q: Sago grain-like vesicular eruption is characteristic of which condition?

Pompholyx. **Explanation:** **1. Why Pompholyx is correct:** Pompholyx, also known as **Dysidrotic Eczema**, is a specific type of vesicular palmoplantar dermatitis. The hallmark clinical feature is the sudden onset of deep-seated, firm, pruritic vesicles on the lateral aspects of the fingers, palms, and soles. Because these vesicles are located beneath the thick stratum corneum of the palms and soles, they do not rupture easily and instead resemble **"sago grains"** (small, translucent, pearl-like bumps). **2. Why the other options are incorrect:** * **Seborrhoeic dermatitis:** Characterized by erythematous plaques with **greasy, yellowish scales** in areas with high sebaceous gland density (scalp, nasolabial folds, chest). It does not present with deep-seated vesicles. * **Atopic dermatitis:** Typically presents as ill-defined erythematous, itchy patches with lichenification in flexural areas (popliteal and antecubital fossae). While it can coexist with pompholyx, "sago grain" vesicles are not its primary morphology. * **Syphilis:** Secondary syphilis commonly involves the palms and soles, but the lesions are typically **copper-colored maculopapules** or "raw ham" colored lesions, often associated with generalized lymphadenopathy and a polymorphic rash. **3. Clinical Pearls for NEET-PG:** * **Triggers:** Emotional stress, heat, and nickel/cobalt sensitivity are common exacerbating factors. * **Cheiropompholyx:** Term used when only the hands are involved. * **Podopompholyx:** Term used when only the feet are involved. * **Management:** High-potency topical corticosteroids are the first-line treatment. * **Differential Diagnosis:** Must be differentiated from Bullous Tinea Pedis (perform a KOH mount) and Pustular Psoriasis.

Question 1

What is the most likely cause of these skin changes?

Accepted Answer

Chronic venous stasis

Answer

Asteatotic eczema

Answer

Necrobiosis lipoidica

Answer

Pretibial myxedema

Question 2

All of the following are exogenous eczema except?

Accepted Answer

Stasis dermatitis

Answer

Irritant dermatitis

Answer

Infective dermatitis

Answer

Photodermatitis

Question 3

All are skin findings in atopic dermatitis, EXCEPT:

Accepted Answer

Black dermatographism

Answer

Facial pallor

Answer

Pityriasis alba

Answer

Keratosis pilaris

Question 4

A 5-year-old boy with a history of atopy presents with multiple asymptomatic oval and circular faintly hypopigmented macules with fine scaling on his face. What is he suffering from?

Accepted Answer

Pityriasis alba

Answer

Acrofacial vitiligo

Answer

Pityriasis versicolor

Answer

Indeterminate leprosy

Question 5

A 30-year-old male presents with pruritic, flat-topped, polygonal, shiny violaceous papules with flexural distribution. What is the most likely diagnosis?

Accepted Answer

Lichen planus

Answer

Psoriasis

Answer

Pityriasis

Answer

Lichenoid dermatitis

Question 6

What is the best initial treatment for acute contact dermatitis?

Accepted Answer

Moist compress

Answer

Topical cream

Answer

Topical ointment

Answer

Emulsion vehicle

Question 7

Which of the following causes allergic contact dermatitis through air?

Accepted Answer

Parthenium

Answer

House dust mite

Answer

Nickel

Answer

Detergents

Question 8

A 19-year-old woman with asthma presents with a chronic, itchy rash distributed on her hands, neck, and elbow creases. Examination reveals thickened skin with increased markings, and fissuring in the elbow creases and hands. What is the most appropriate management advice?

Accepted Answer

Environmental manipulation

Answer

Psychoanalysis

Answer

Wearing warm clothing

Answer

Maintaining a dry environment

Question 9

Perioral pallor and Dennie's lines are seen in which condition?

Accepted Answer

Atopic dermatitis

Answer

Chronic actinic dermatitis

Answer

Blood dyscrasias

Answer

Perioral contact dermatitis

Question 10

Sago grain-like vesicular eruption is characteristic of which condition?

Accepted Answer

Pompholyx

Answer

Seborrhoeic dermatitis

Answer

Atopic dermatitis

Answer

Syphilis

Dermatitis and Eczema — MCQs

Dermatitis and Eczema — MCQs

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