Dermatitis and Eczema Practice Questions

Q: A 27-year-old woman presents with a painful blistering rash on her right shoulder after a hiking trip. She reports recent exposure to poison ivy. What is the most likely diagnosis?

Contact dermatitis. ***Contact dermatitis*** - The patient's history of **recent exposure to poison ivy** and the development of a **painful blistering rash** are classic signs of allergic contact dermatitis. - Poison ivy contains **urushiol oil**, a potent allergen that triggers a **type IV hypersensitivity reaction** characterized by inflammation, pruritus, erythema, and vesicles or bullae. *Impetigo* - Impetigo is a **bacterial skin infection** characterized by **honey-crusted lesions** or pustules, often associated with *Staphylococcus aureus* or *Streptococcus pyogenes*. - It usually occurs in children and is not typically linked to environmental allergen exposure or a primary blistering rash in this manner. *Herpes zoster* - Herpes zoster (shingles) is caused by the **reactivation of the varicella-zoster virus** and presents as a **painful vesicular rash** in a **dermatomal distribution**. - While blistering can occur, the key differentiator here is the lack of a dermatomal pattern and the clear history of direct exposure to an irritant (poison ivy). *Bullous pemphigoid* - Bullous pemphigoid is an **autoimmune blistering disease** that typically affects **elderly individuals** with large, tense bullae on an erythematous or non-erythematous base. - It does not usually present acutely after environmental exposure like poison ivy, nor is it common in a 27-year-old.

Q: A 40-year-old female presents with a pruritic rash on her hands after using a new soap. Patch testing shows a positive reaction to the fragrance mix. What is the most appropriate management?

Avoidance of fragrance-containing products. ***Avoidance of fragrance-containing products*** - A **positive patch test** to a fragrance mix confirms an **allergic contact dermatitis** reaction to fragrances. - The most effective management for allergic contact dermatitis is the **identification and complete avoidance of the offending allergen**. *Topical antibiotics* - Topical antibiotics are indicated for **bacterial skin infections**, such as impetigo or infected eczema. - This patient presents with an **allergic reaction**, not an infection, so antibiotics would not address the underlying cause. *Systemic corticosteroids* - Systemic corticosteroids are used for **severe, widespread inflammatory conditions** or acute severe allergic reactions. - While they can reduce inflammation, they are typically **not the first-line treatment** for localized allergic contact dermatitis and carry more significant side effects than avoidance. *UVB phototherapy* - **UVB phototherapy** is a treatment for chronic skin conditions like **psoriasis** or **severe eczema**. - It is **not indicated for acute allergic contact dermatitis**, as it does not address the allergic trigger.

Q: A 5-year-old child presents with intense itching and erythematous papules on the extensor surfaces of the arms and legs. What is the most likely diagnosis?

Atopic dermatitis. ***Atopic dermatitis*** - **Atopic dermatitis** (eczema) is the most likely diagnosis given the **intense itching** (pruritus is the hallmark feature) and **erythematous papules**. - In children aged **2-5 years**, atopic dermatitis commonly affects **extensor surfaces** of the arms and legs, representing the transition from infantile to childhood patterns. - While flexural involvement becomes more typical in older children (>5 years), extensor distribution at age 5 is still very common and characteristic. - The intense pruritus described is pathognomonic for atopic dermatitis. *Psoriasis* - **Psoriasis** does present on extensor surfaces with well-demarcated **erythematous plaques with silvery scales**, particularly on elbows and knees. - However, **intense itching is NOT a primary feature** of psoriasis; it is typically mildly pruritic or non-pruritic. - The prominent pruritus in this case makes psoriasis unlikely. *Contact dermatitis* - **Contact dermatitis** results from exposure to an **allergen or irritant**, causing a localized rash. - The distribution typically conforms to the contact area and would be less likely to present symmetrically on multiple extensor surfaces without a clear exposure history. - The pattern described is more consistent with an endogenous dermatitis. *Scabies* - **Scabies** causes intense itching (worse at night) with characteristic **burrows, papules, and excoriations**. - Typical sites include **interdigital spaces, wrists, axillae, waistline, and genitalia**, not primarily extensor surfaces of arms and legs. - The distribution pattern does not fit scabies.

Q: Identify the skin condition shown in the image.

Intertrigo. ***Intertrigo*** - This condition is characterized by **redness, maceration, and sometimes erosion** within skin folds, often exacerbated by **heat, moisture, and friction**. - It commonly affects areas such as the **groin, axillae**, and beneath the breasts. *Miliaria* - This refers to **heat rash** caused by blocked sweat ducts, leading to small, itchy, sometimes painful bumps or blisters. - While it occurs in hot, moist environments, it typically presents as **small papules** or vesicles rather than broad areas of maceration in skin folds. *Atopic dermatitis* - Also known as eczema, it is characterized by **dry, itchy, inflamed skin**, often with a chronic, relapsing course. - While it can appear in skin folds (**flexural eczema**), it typically involves papules, lichenification, and xerosis, which are not the predominant features here. *Bacterial skin infection* - While a bacterial infection (e.g., impetigo, cellulitis) can cause redness and inflammation, it often presents with **purulent discharge, crusting, or significant warmth/tenderness**, which are not consistently described. - Intertrigo can become secondarily infected, but the primary condition itself is not bacterial in origin.

Q: What condition is likely to be present in the child shown in the image, whose mother has asthma?

Atopic dermatitis. ***Atopic dermatitis*** - The image shows an infant with **red, scaly, and irritated skin**, particularly on the cheeks and around the mouth, consistent with the characteristic presentation of **atopic dermatitis (eczema)** in infants. - Atopic dermatitis often occurs in individuals with a family history of **atopy**, which includes conditions like **asthma**, allergic rhinitis, and food allergies; a mother with asthma significantly increases the child's risk. *SLE* - **Systemic lupus erythematosus (SLE)** is a **chronic autoimmune inflammatory disease** that rarely presents in infancy with such prominent skin findings, especially without other systemic symptoms. - Skin manifestations of SLE typically include a **malar (butterfly) rash** or **discoid lesions**, which are different from the diffuse eczematous rash seen here. *Erythema* - **Erythema** simply refers to **redness of the skin** caused by inflammation or dilation of blood capillaries. - While the infant's skin is erythematous, erythema is a **symptom**, not a specific diagnosis, and does not fully describe the scaly, papular nature of the rash or the underlying condition. *TEN* - **Toxic epidermal necrolysis (TEN)** is a **severe, life-threatening skin condition** characterized by widespread epidermal detachment, forming large blisters and skin sloughing, often triggered by medications. - The skin lesions in the image do not show the extensive blistering and denudation characteristic of TEN, and a history of an asthmatic mother is not a risk factor for TEN.

Q: A child presents with a rash in the neck folds as shown in the image. The area appears erythematous with satellite lesions and maceration. What is the most likely diagnosis?

Intertrigo. ***Intertrigo*** - The image shows a reddened, inflamed rash in skin folds (neck creases), which is characteristic of **intertrigo**. This condition results from skin-on-skin friction, moisture, and warmth. - The rash appears to have satellite lesions and a somewhat macerated appearance, which would be consistent with secondary fungal (e.g., Candida) or bacterial infection, common complications of intertrigo. *Heat rash* - **Heat rash (miliaria)** typically presents as small, itchy red bumps or clear blisters, often found in areas prone to sweating. - While it can occur in skin folds, the diffuse, raw-looking erythema and presence of potential satellite lesions shown in the image are less typical for simple heat rash. *Eczema* - **Eczema (atopic dermatitis)** is characterized by dry, itchy, inflamed skin, often with scaling, crusting, or lichenification during chronic stages. - While eczema can affect skin folds, the appearance in the image (intense redness, maceration, potential satellite lesions) is more suggestive of an irritant or infectious process like intertrigo rather than typical eczema. *Impetigo* - **Impetigo** is a bacterial skin infection characterized by honey-colored crusts, vesicles, or bullae, typically appearing anywhere on the body, especially around the nose and mouth. - The rash in the image lacks the characteristic honey-colored crusts or vesiculobullous lesions associated with impetigo.

Q: What condition is likely to develop in a child with a mother who has asthma?

Atopic dermatitis. ***Atopic dermatitis*** - **Atopic dermatitis** is strongly associated with a family history of **atopy**, which includes **asthma**, allergic rhinitis, and eczema. - Children of mothers with asthma have a significantly increased risk of developing atopic conditions due to **genetic predisposition** and shared immunological pathways. - This is part of the **atopic march** where children often develop atopic dermatitis first, followed by other atopic conditions. *SLE* - **Systemic lupus erythematosus (SLE)** is a systemic autoimmune disease not directly linked to a maternal history of asthma. - While it has a genetic component, it is distinct from the **atopic** disease spectrum. *Erythema multiforme* - **Erythema multiforme** is a hypersensitivity reaction typically triggered by infections (especially HSV) or medications. - It is not associated with maternal asthma or the atopic disease spectrum. - It presents with characteristic target lesions on skin and mucous membranes. *TEN* - **Toxic epidermal necrolysis (TEN)** is a severe, life-threatening skin reaction, most often drug-induced. - There is no known direct association between maternal asthma and the development of TEN in offspring.

Q: A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?

Atopic dermatitis. ***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.

Q: Most common flexural site for atopic dermatitis -

Elbow crease. ***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.

Q: Which of the following organisms has a role to play in Seborrheic dermatitis?

Pityrosporum ovale. ***Pityrosporum ovale*** - **Pityrosporum ovale**, now known as **Malassezia furfur**, is a lipophilic yeast that colonizes the skin and plays a significant role in the pathogenesis of **seborrheic dermatitis**. - Its presence is commonly associated with the inflammatory response seen in seborrheic dermatitis, though the exact mechanism is not fully understood. *Candida albicans* - **Candida albicans** is a common cause of **mucocutaneous candidiasis** and **intertrigo**, but it is not directly implicated in the etiology of seborrheic dermatitis. - While it can cause skin infections, its typical presentation involves erythematous, macerated rashes with satellite lesions in skin folds. *Propionibacterium* - **Propionibacterium acnes**, now known as **Cutibacterium acnes**, is primarily associated with the pathogenesis of **acne vulgaris**. - It plays a role in the inflammation and comedone formation characteristic of acne, not the scaling and erythema of seborrheic dermatitis. *None of the above* - This option is incorrect because **Pityrosporum ovale (Malassezia furfur)** is a well-recognized organism involved in seborrheic dermatitis. - The other organisms listed are associated with different dermatological conditions.

Question 1

A 27-year-old woman presents with a painful blistering rash on her right shoulder after a hiking trip. She reports recent exposure to poison ivy. What is the most likely diagnosis?

Accepted Answer

Contact dermatitis

Answer

Impetigo

Answer

Herpes zoster

Answer

Bullous pemphigoid

Question 2

A 40-year-old female presents with a pruritic rash on her hands after using a new soap. Patch testing shows a positive reaction to the fragrance mix. What is the most appropriate management?

Accepted Answer

Avoidance of fragrance-containing products

Answer

Topical antibiotics

Answer

Systemic corticosteroids

Answer

UVB phototherapy

Question 3

A 5-year-old child presents with intense itching and erythematous papules on the extensor surfaces of the arms and legs. What is the most likely diagnosis?

Accepted Answer

Atopic dermatitis

Answer

Contact dermatitis

Answer

Scabies

Answer

Psoriasis

Question 4

Identify the skin condition shown in the image.

Accepted Answer

Intertrigo

Answer

Miliaria

Answer

Atopic dermatitis

Answer

Bacterial skin infection

Question 5

What condition is likely to be present in the child shown in the image, whose mother has asthma?

Accepted Answer

Atopic dermatitis

Answer

SLE

Answer

Erythema

Answer

TEN

Question 6

A child presents with a rash in the neck folds as shown in the image. The area appears erythematous with satellite lesions and maceration. What is the most likely diagnosis?

Accepted Answer

Intertrigo

Answer

Heat rash

Answer

Eczema

Answer

Impetigo

Question 7

What condition is likely to develop in a child with a mother who has asthma?

Accepted Answer

Atopic dermatitis

Answer

SLE

Answer

Erythema multiforme

Answer

TEN

Question 8

A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?

Accepted Answer

Atopic dermatitis

Answer

Seborrheic dermatitis

Answer

Allergic contact dermatitis

Answer

Erysipelas

Question 9

Most common flexural site for atopic dermatitis -

Accepted Answer

Elbow crease

Answer

Popliteal fossa

Answer

Scalp

Answer

Trunk

Question 10

Which of the following organisms has a role to play in Seborrheic dermatitis?

Accepted Answer

Pityrosporum ovale

Answer

Propionibacterium

Answer

Candida albicans

Answer

None of the above

Dermatitis and Eczema — MCQs

Dermatitis and Eczema — MCQs

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