Atopic Dermatitis — MCQs
Which type of dermatitis is evaluated through patch testing?
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?
Which of the following is a contraindication to topical steroids?
Which condition is characterized by perioral pallor and Dennie-Morgan folds?
Most common flexural site for atopic dermatitis -
A child presented with itchy plaques over the neck, the bilateral popliteal and cubital fossa. What could be the diagnosis?
A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?
Which of the following is the MOST contraindicated condition for steroid use?
A 24-year-old male presents with asymptomatic scaly lesions over the body as shown in the image below. What is the likely diagnosis?
Parakeratosis is defined as:
Atopic Dermatitis Indian Medical PG Practice Questions and MCQs
Question 1: Which type of dermatitis is evaluated through patch testing?
- A. Atopic dermatitis
- B. Irritant contact dermatitis
- C. Discoid eczema
- D. Contact dermatitis due to allergens (Correct Answer)
Explanation: ***Contact dermatitis due to allergens*** - **Patch testing** is specifically used to identify specific **allergens** that trigger an **allergic contact dermatitis** reaction. - It involves applying suspected allergens to the skin and observing for a localized inflammatory response, indicating delayed type IV hypersensitivity. *Atopic dermatitis* - This is a chronic inflammatory skin condition characterized by **eczematous lesions** and severe **pruritus**, often linked to a genetic predisposition and immune dysfunction. - While allergy testing (e.g., prick tests, blood tests for IgE) might be used to identify triggers, **patch testing** is not the primary diagnostic tool for atopic dermatitis itself. *Irritant contact dermatitis* - This type of dermatitis is caused by direct **damage to the skin barrier** from exposure to caustic substances or irritants, not an immune-mediated allergic reaction. - Diagnosis is usually based on clinical history of exposure and symptom presentation, and **patch testing** is typically negative in these cases. *Discoid eczema* - Also known as **nummular dermatitis**, this condition presents with distinctive **coin-shaped lesions** and is often associated with dry skin or skin trauma. - Its etiology is generally unknown and not attributable to specific allergens detectable by **patch testing**.
Question 2: 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.
Question 3: Which of the following is a contraindication to topical steroids?
- A. Dendritic ulcer (Correct Answer)
- B. Herpetic stromal keratitis without epithelial defect
- C. Elevated intraocular pressure
- D. Non-infectious anterior uveitis
Explanation: ***Dendritic ulcer*** - A **dendritic ulcer** is characteristic of **herpes simplex keratitis**, which is an active viral infection of the cornea. - **Topical steroids** are contraindicated because they can suppress the immune response, leading to viral replication, corneal melt, and potentially severe vision loss or perforation. *Herpetic stromal keratitis without epithelial defect* - In cases of **stromal keratitis**, where the infection is deeper and an intact epithelium is present, topical steroids may be used cautiously in conjunction with antiviral agents to reduce inflammation and scarring. - The primary concern with steroids in herpes simplex keratitis is activating viral replication in the presence of an **epithelial defect**, which is not present here. *Elevated intraocular pressure* - **Elevated intraocular pressure** is a known side effect of topical steroid use, especially with prolonged administration, but it is not an absolute contraindication in itself. - It necessitates careful monitoring and may require concurrent glaucoma treatment, but the primary condition needing steroids may still warrant their use. *Non-infectious anterior uveitis* - **Topical corticosteroids** are the **mainstay of treatment** for non-infectious anterior uveitis to reduce inflammation and prevent complications such as synechiae and vision loss. - The benefits of controlling inflammation in uveitis generally outweigh the risks associated with judicious steroid use.
Question 4: Which condition is characterized by perioral pallor and Dennie-Morgan folds?
- A. Atopic dermatitis (Correct Answer)
- B. Chronic actinic dermatitis
- C. Blood dyscrasia
- D. Perioral contact dermatitis
Explanation: ***Atopic dermatitis*** - **Perioral pallor** (paleness around the mouth) and **Dennie-Morgan folds** (infraorbital folds) are classic cutaneous manifestations observed in atopic dermatitis. - These features, along with xerosis, lichenification, and eczema, form part of the diagnostic criteria for this chronic inflammatory skin condition. *Chronic actinic dermatitis* - This condition is characterized by an **eczematous eruption** in **sun-exposed areas**, such as the face, neck, and dorsal hands. - It does not typically present with perioral pallor or Dennie-Morgan folds, which are specific to atopic predispositions. *Blood dyscrasia* - Blood dyscrasias are disorders affecting the blood components and can manifest with various skin findings, like **purpura**, **pallor due to anemia**, or **ulcers**. - However, they do not specifically cause perioral pallor in the characteristic pattern seen with atopic dermatitis or Dennie-Morgan folds. *Perioral contact dermatitis* - This condition is an **inflammatory skin response** to a **topical irritant or allergen** applied around the mouth. - It usually presents with erythema, scaling, and sometimes vesicles in the area of contact, rather than generalized perioral pallor or Dennie-Morgan folds.
Question 5: Most common flexural site for atopic dermatitis -
- A. Popliteal fossa
- B. Elbow crease (Correct Answer)
- C. Scalp
- D. Trunk
Explanation: ***Elbow crease*** - The **antecubital fossa** (elbow crease) and **popliteal fossa** (knee crease) are the **two most characteristic flexural sites** for atopic dermatitis in children and adults. - Both sites are **equally common** and represent classic presentations of flexural eczema. - The constant rubbing, friction, and moisture retention in these areas contribute to skin irritation and the characteristic **lichenification** seen in atopic dermatitis. - In the context of this question asking for "most common," both antecubital and popliteal fossae are considered the primary flexural sites. *Popliteal fossa* - The **popliteal fossa** (behind the knee) is equally as common as the antecubital fossa and is a classic flexural site for atopic dermatitis. - It shares the same pathophysiological mechanisms and clinical presentation as the elbow crease. - Both antecubital and popliteal fossae are mentioned together in standard dermatology texts as the hallmark flexural sites. *Scalp* - While the scalp can be affected by atopic dermatitis, especially in **infants** (as **seborrheic dermatitis** or cradle cap), it is **not a flexural site**. - Scalp involvement typically presents as scaling and erythema, rather than the lichenified plaques characteristic of flexural eczema. *Trunk* - The trunk can be affected by atopic dermatitis with diffuse patches or widespread xerosis, but it is **not a flexural site**. - Flexural areas (skin folds) are the characteristic locations for atopic dermatitis in the flexural pattern.
Question 6: 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 7: 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 8: Which of the following is the MOST contraindicated condition for steroid use?
- A. Herpetic keratitis
- B. Exposure keratitis
- C. Atopic dermatitis
- D. Fungal corneal ulcer (Correct Answer)
Explanation: ***Fungal corneal ulcer*** - Steroids are **immunomodulatory** and can suppress the immune response, which is crucial for fighting fungal infections [1]. - Using steroids in cases of fungal keratitis can lead to rapid **worsening of the infection**, potentially causing vision loss or even globe rupture. *Herpetic keratitis* - While steroids can exacerbate active **herpes simplex virus (HSV) epithelial keratitis**, they are often used cautiously in certain forms of herpetic keratitis, such as **stromal keratitis** or **endotheliitis**, under antiviral coverage to control inflammation. - The key is proper diagnosis to differentiate epithelial (contraindicated) from stromal/endothelial (potentially indicated with antivirals) forms. *Exposure keratitis* - This condition is caused by **incomplete eyelid closure** leading to corneal drying and damage, not primarily by inflammation requiring steroid suppression. - Management focuses on **lubrication** and protecting the surface, and steroids are generally not indicated. *Atopic dermatitis* - **Topical corticosteroids** are the mainstay of treatment for atopic dermatitis due to their potent **anti-inflammatory** effects [2]. - This condition is an inflammatory skin disorder, and steroids help to reduce inflammation, itching, and redness [3].
Question 9: A 24-year-old male presents with asymptomatic scaly lesions over the body as shown in the image below. What is the likely diagnosis?
- A. Atopic Dermatitis
- B. Lichen planus
- C. Seborrheic Dermatitis
- D. Pityriasis Rosea (Correct Answer)
Explanation: ***Pityriasis Rosea*** - The image shows numerous **scaly, erythematous plaques** distributed over the trunk, with a characteristic "Christmas tree" pattern often observed in Pityriasis Rosea. - The lesions are described as **asymptomatic**, which is consistent with Pityriasis Rosea, although mild pruritus can occur. *Atopic Dermatitis* - Typically presents with **intensely pruritic, erythematous, and eczematous lesions** often found in flexural areas (e.g., antecubital and popliteal fossae). - While it can be widespread, the morphology of the lesions (eczematous vs. scaly plaques) and the absence of pruritus make this less likely. *Lichen planus* - Characterized by **pruritic, violaceous, polygonal papules** and plaques, often appearing on the flexor surfaces of wrists, ankles, and oral mucosa. - The appearance of the lesions in the image does not match the typical morphology of lichen planus. *Seborrheic Dermatitis* - Primarily affects areas with a high density of sebaceous glands, such as the **scalp, face (nasolabial folds, eyebrows), and chest**. - Presents with **greasy, yellowish scales** on an erythematous base, which is distinct from the dry, scaly plaques seen in the image.
Question 10: Parakeratosis is defined as:
- A. Decreased thickness of stratum corneum
- B. Retention of cytoplasmic contents in stratum corneum
- C. Increased thickness in stratum corneum
- D. Retention of nuclei in stratum corneum (Correct Answer)
Explanation: ***Retention of nuclei in stratum corneum*** - **Parakeratosis** is a histological term defining the abnormal retention of **nuclei** within the cells of the **stratum corneum** [1]. - This indicates incomplete or abnormal keratinization, where keratinocytes fail to fully mature and lose their nuclei as they reach the uppermost layer of the epidermis [1]. *Decreased thickness of stratum corneum* - A decreased thickness of the **stratum corneum** is referred to as **atrophy** or thinning, which is not the definition of parakeratosis. - This typically indicates a reduction in the number of cell layers, not the presence of nuclei within those layers. *Retention of cytoplasmic contents in stratum corneum* - While cells normally lose most of their cytoplasmic organelles during the keratinization process, the defining feature of parakeratosis specifically refers to the retention of the **nucleus**. - The presence of cytoplasmic contents without nuclei would not be termed parakeratosis. *Increased thickness in stratum corneum* - An increased thickness of the **stratum corneum** is known as **hyperkeratosis**. - Hyperkeratosis can occur with or without parakeratosis, but the presence of nuclei is the key characteristic of parakeratosis, not merely the thickness. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Disorders Involving Inflammatory And Haemopoietic Cells, pp. 640-641.
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