The image shows presence of:

All are causes of the skin lesion shown except:

The image shows:

The clinical sign shown in the image is:

This patient was cleaning the basement, following which he developed the lesions as shown on his back for the last 6 hours. The image shows presence of:

The following strip is used for testing of:

A child has a pruritic rash as shown below. His mother is an asthmatic. Comment on the diagnosis:

A child presented with itchy plaques over the neck, the bilateral popliteal and cubital fossa. What could be the diagnosis?
Dennie-Morgan fold is indicative of:
A patient comes to you with skin reactions after visiting the hair dresser. What will you do to confirm the diagnosis of contact dermatitis?
Explanation: ***Onychogryphosis*** - The image clearly shows a thickened, **curved**, and discolored nail, often described as resembling a **ram's horn**, which is characteristic of onychogryphosis. - This condition results from an imbalance in nail growth, leading to hypertrophy and abnormal curvature, often seen in the elderly or due to trauma. *Onycholysis* - Onycholysis is the **separation of the nail plate from the nail bed**, typically starting at the distal end. - The image does not show a clear separation of the nail from its bed, but rather a deformed, thickened nail plate. *Trachyonychia* - Trachyonychia is characterized by **rough**, opaque, and sometimes vertically ridged nails, often described as having a "sandpapered" appearance. - While there is some discoloration, the predominant feature in the image is the extreme thickening and curvature, not uniform roughness. *Onychocryptosis* - Onychocryptosis, commonly known as an **ingrown nail**, occurs when the edge of the nail grows into the surrounding skin. - The image does not depict an ingrown nail; instead, it shows a nail with significant hypertrophy and deformation of the nail plate itself.
Explanation: ***Chronic renal failure*** - The image depicts **erythema multiforme**, a hypersensitivity reaction characterized by **target lesions**. - **Chronic renal failure** is not a known direct cause of erythema multiforme. *Infectious mononucleosis* - **Viral infections**, including **Epstein-Barr virus** (which causes infectious mononucleosis), are common triggers for erythema multiforme. - The immune response to the viral infection can lead to the characteristic skin lesions. *Mycoplasma* - **Mycoplasma pneumoniae infection** is a well-established cause of erythema multiforme, particularly in children and young adults. - Mycoplasma is one of the most common infectious triggers and can also cause other severe mucocutaneous reactions. *Collagen vascular disease* - Certain **collagen vascular diseases**, such as **systemic lupus erythematosus**, can be associated with erythema multiforme. - The underlying autoimmune dysregulation can trigger generalized hypersensitivity reactions.
Explanation: ***Atopic dermatitis*** - The image displays characteristic features of **atopic dermatitis**, including **erythema**, **scaling**, and **lichenification**, particularly visible on the foot. - The skin appears dry, thickened, and inflamed, consistent with chronic eczema often associated with atopic dermatitis. *Allergic shiners* - **Allergic shiners** are dark circles under the eyes caused by venous congestion due to allergies, which are not depicted in this image of a foot. - This condition is a facial sign and unrelated to the skin findings shown. *Allergic line* - The term "allergic line" or **Dennie-Morgan folds** refers to extra folds of skin under the lower eyelids, also a facial sign of allergies, not seen here. - The image presents a skin condition on the foot, not a facial feature. *Acute urticaria* - **Acute urticaria** (hives) presents as transient, raised, itchy **wheals** with well-demarcated borders, which are not consistent with the chronic, scaly, and thickened appearance of the skin in the image. - The lesions in the image show thickening and inflammation, typical of a more chronic dermatological condition rather than the transient nature of acute urticaria.
Explanation: ***Dennie-Morgan fold (infraorbital fold)*** - The image clearly shows a prominent **infraorbital fold** or crease below the lower eyelid. - This crease is known as **Dennie-Morgan fold** (also called Dennie-Morgan lines) and is a common finding in individuals with atopic dermatitis or chronic allergic conditions. - It represents an accentuated line or fold in the skin of the lower eyelid and is considered a minor diagnostic criterion for atopic dermatitis. *Allergic salute* - An **allergic salute** refers to the characteristic gesture where a child repeatedly pushes the tip of the nose upward with the palm of the hand to relieve nasal itching and obstruction. - This action often leads to a transverse crease across the bridge of the nose, but it is not depicted in the image. *Allergic line* - The term **allergic line** (or allergic crease) is synonymous with the transverse nasal crease resulting from the allergic salute. - While it's a sign associated with chronic allergic rhinitis, it does not describe the infraorbital fold seen in the image. *Allergic shiners* - **Allergic shiners** are dark, discolored areas under the eyes, resembling bruises, caused by venous congestion secondary to chronic allergic rhinitis or nasal obstruction. - While allergic shiners may coexist with Dennie-Morgan folds, the prominent feature indicated in the image is the infraorbital fold itself, not periorbital darkening.
Explanation: ***Acute urticaria*** - The image shows widespread, erythematous, edematous, and **pruritic wheals** (hives) on the back, consistent with **acute urticaria**. - The sudden onset after cleaning the basement suggests an acute allergic reaction or contact with an irritant, leading to mast cell degranulation and histamine release. *Atopic dermatitis* - This condition typically presents with **eczematous lesions**, characterized by dry, itchy, inflamed skin, often with lichenification in chronic cases. - The lesions in the image are distinct wheals, not the typical presentation of atopic dermatitis. *Cholinergic urticaria* - This form of urticaria is triggered by **increases in body temperature**, such as exercise, hot baths, or emotional stress, rarely by cleaning a basement. - It usually manifests as small, pinpoint wheals surrounded by a flare, which is different from the large, confluent wheals shown. *Dermographism* - **Dermographism** is a physical urticaria where wheals appear along lines of pressure or scratching on the skin, literally "writing on the skin." - While it involves wheals, the distribution in the image is generalized and not confined to areas of pressure or linear scratching, making it inconsistent with dermographism.
Explanation: ***Contact dermatitis (Allergic)*** - The image depicts a **patch test** strip, characterized by multiple small chambers containing various allergens, which are applied to the skin. - This method is the **gold standard** for identifying specific substances that cause **allergic contact dermatitis** by observing localized inflammatory reactions after 48-72 hours. - Patch testing detects **Type IV delayed hypersensitivity** reactions to specific allergens. *Atopic dermatitis* - While atopic dermatitis is a type of eczema, it is primarily diagnosed based on **clinical criteria** (e.g., pruritus, typical morphology and distribution), family history, and elevated IgE levels. - Patch testing is generally not the primary diagnostic tool for atopic dermatitis, as it is primarily a **Type I hypersensitivity** reaction, whereas patch tests detect Type IV reactions. *Seborrheic dermatitis* - Seborrheic dermatitis is a chronic inflammatory condition affecting sebum-rich areas (scalp, face, chest). - Diagnosis is made **clinically** based on characteristic greasy, yellowish scales in typical distributions. - Patch testing is not used for diagnosis of seborrheic dermatitis. *Irritant contact dermatitis* - Irritant contact dermatitis results from **direct chemical damage** to the skin rather than an allergic immune response. - It is diagnosed primarily through **clinical history** and distribution pattern of lesions. - Patch testing is specifically designed to identify **allergic** (not irritant) contact dermatitis, as irritant reactions are non-immunological.
Explanation: ***Atopic dermatitis*** - The image shows a classic presentation of **eczematous rash** in the **flexural areas** (knees), which is characteristic of atopic dermatitis. - The history of a **mother with asthma** suggests an **atopic diathesis**, increasing the likelihood of atopic dermatitis in the child due to its strong genetic component and association with other atopic conditions (asthma, allergic rhinitis). *Seborrheic dermatitis* - Typically presents as **greasy, yellowish scales** on an erythematous base, commonly affecting the scalp, face (eyebrows, nasolabial folds), and chest. - While it can occur in infants ("cradle cap"), its morphology and locations are distinct from the rash seen in the image. *Allergic contact dermatitis* - This rash would typically be localized to areas of direct contact with an **allergen** and would not necessarily show the typical flexural distribution seen in the image. - It often presents with more acute **vesicles, bullae, and intense pruritus** strictly limited to the exposure site. *Erysipelas* - Erysipelas is a **superficial bacterial skin infection** characterized by a **well-demarcated, erythematous, raised, and warm plaque**, often with systemic symptoms like fever and chills. - The rash in the image does not present with the characteristic features of an acute bacterial infection.
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.
Explanation: ***Atopic dermatitis*** - A **Dennie-Morgan fold** is an extra crease or fold in the skin below the lower eyelid, which is a common but not exclusive indicator for **atopic dermatitis**, also known as **eczema**. - Its presence suggests chronic inflammation and edema around the eyes, characteristic of this allergic skin condition. *Leprosy* - **Leprosy** primarily affects nerves, skin, eyes, and the upper respiratory tract but does not typically cause **Dennie-Morgan folds**. - Its characteristic skin lesions involve nodules, macules, and loss of sensation. *Dermatitis herpetiformis* - **Dermatitis herpetiformis** is an intensely itchy, chronic blistering skin condition associated with **celiac disease**. - It presents with symmetrical papules and vesicles, predominantly on extensor surfaces, and is not linked to periorbital folds. *TB* - **Tuberculosis (TB)** is a bacterial infection primarily affecting the lungs but can manifest in other organs. - Skin manifestations of TB, like lupus vulgaris or scrofuloderma, are rare and do not include the **Dennie-Morgan fold**.
Explanation: ***Patch Test*** - A **patch test** is the gold standard for diagnosing **allergic contact dermatitis** by directly applying suspected allergens to the skin. - This test identifies specific substances that cause a delayed hypersensitivity reaction, which is characteristic of contact dermatitis. *S IgE* - **Serum IgE** levels are primarily indicative of **Type I hypersensitivity** reactions, such as allergic rhinitis or asthma. - Contact dermatitis is a **Type IV delayed hypersensitivity reaction**, not mediated by IgE antibodies. *Allergy Test* - The term "allergy test" is broad and can refer to various methods including skin prick tests, IgE blood tests, or patch tests. - Without specifying **patch testing**, other forms of allergy tests are less appropriate for diagnosing contact dermatitis, as they target different immune mechanisms. *VDRL* - **VDRL (Venereal Disease Research Laboratory)** test is used to screen for **syphilis**, a sexually transmitted infection. - It has no relevance to the diagnosis of contact dermatitis, which is an inflammatory skin condition caused by contact with an allergen or irritant.
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