Food Allergies Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Food Allergies. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Food Allergies Indian Medical PG Question 1: A man had Egg omelet 1-4 hours back and developed diarrhea, vomiting and abdominal cramps. Most likely cause of poisoning is
- A. Bacillus cereus
- B. Clostridium
- C. Staphylococcus (Correct Answer)
- D. Salmonella
Food Allergies Explanation: ***Staphylococcus***
- **Staphylococcal food poisoning** is characterized by a rapid onset (1-6 hours, most commonly 2-4 hours) of symptoms like **nausea**, **vomiting**, **abdominal cramps**, and **diarrhea** after consuming contaminated food.
- Omelets prepared with eggs can be a source if handled improperly, allowing pre-formed **heat-stable enterotoxins** produced by *Staphylococcus aureus* to cause illness, even if the bacteria themselves are killed by cooking.
*Bacillus cereus*
- This organism can cause two types of food poisoning: diarrheal and emetic. The **emetic type**, characterized by prominent vomiting, has a rapid onset (0.5-6 hours, usually 1-5 hours) often associated with *rice products* contaminated with **heat-stable toxin**.
- While vomiting is present, the consumption of an omelet and the typical 1-4 hour timeframe match Staphylococcal more closely, and *Bacillus cereus* diarrheal type usually has a longer incubation (6-15 hours).
*Clostridium*
- **Clostridium perfringens** food poisoning typically causes primarily **diarrhea** and **abdominal cramps** with less prominent vomiting, and has a longer incubation period of 6-24 hours.
- **Clostridium botulinum** causes a neuroparalytic illness, not primarily gastroenteritis, and is associated with improperly canned foods.
*Salmonella*
- **Salmonella food poisoning** usually has a longer incubation period, typically 12-72 hours (average 12-36 hours), with symptoms including diarrhea, fever, and abdominal cramps.
- The **rapid onset** (1-4 hours) in this case makes Salmonella less likely, as it primarily causes infection rather than pre-formed toxin ingestion.
Food Allergies Indian Medical PG Question 2: 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)
Food Allergies 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**.
Food Allergies Indian Medical PG Question 3: A man takes peanut and develops tongue swelling, neck swelling, stridor, hoarseness of voice. What is the probable diagnosis?
- A. FB in larynx
- B. Angioneurotic edema (Correct Answer)
- C. Parapharyngeal abscess
- D. FB bronchus
Food Allergies Explanation: Andioneurotic edema
- The combination of **tongue swelling**, **neck swelling**, **stridor**, and **hoarseness of voice** following peanut ingestion is highly suggestive of **angioneurotic edema**, a severe allergic reaction that can lead to airway obstruction [1].
- This is a life-threatening condition requiring immediate medical intervention, often associated with generalized **anaphylaxis** when triggered by allergens [2].
*FB in larynx*
- While a **foreign body (FB) in the larynx** can cause stridor and hoarseness, the widespread swelling of the tongue and neck points away from a localized laryngeal obstruction [3].
- A laryngeal FB would typically be associated with a more sudden onset of choking and coughing, not diffuse edema [3].
*Parapharyngeal abscess*
- A **parapharyngeal abscess** would typically present with **fever**, **severe throat pain**, and **trismus** (difficulty opening the mouth), which are not mentioned in this scenario.
- The acute, rapid onset of symptoms after peanut consumption is inconsistent with the slower progression of an abscess.
*FB bronchus*
- A **foreign body in the bronchus** would primarily cause **coughing**, **wheezing**, and possibly **respiratory distress**, often unilateral, rather than severe global swelling of the tongue and neck.
- Inspiratory stridor and hoarseness are more indicative of upper airway involvement than bronchial obstruction.
Food Allergies Indian Medical PG Question 4: In chronic allergy, which Ig is more persistent in the body?
- A. Ig A
- B. Ig E (Correct Answer)
- C. Ig G
- D. Ig M
Food Allergies Explanation: ***Ig E***
- **IgE** is the primary antibody involved in **allergic reactions**, binding to receptors on **mast cells** and **basophils** to trigger histamine release.
- In chronic allergy, sustained exposure to allergens leads to continuous production of IgE, making it a **persistent** and dominant immunoglobulin in the allergic response.
*Ig A*
- **IgA** is mainly found in **mucosal secretions**, such as tears, saliva, and gut, protecting against pathogens at these sites.
- While important for immunity, IgA does not play a direct role in the **immediate hypersensitivity reactions** characteristic of chronic allergies.
*Ig G*
- **IgG** is the most abundant antibody in serum, providing **long-term immunity** against pathogens through neutralization, opsonization, and complement activation.
- Though present, IgG is not the **primary mediator** of the **allergic response** in chronic allergy, instead often associated with protective immunity or certain non-IgE mediated hypersensitivities.
*Ig M*
- **IgM** is the first antibody produced during a **primary immune response** and is effective at activating the complement system.
- It is predominantly found in the bloodstream and functions as a **short-term defender**, but it is not directly involved in the pathogenesis or persistence of chronic allergies.
Food Allergies Indian Medical PG Question 5: A 45-year-old patient with a known allergy to penicillin presents with an enterococcal endocarditis. The physician needs to prescribe an antibiotic but wants to ensure it is safe for a penicillin allergy. The patient has had previous allergic reactions to penicillin including rash & swelling. Which of the following drugs can be used safely in a patient allergic to penicillin?
- A. Ceftriaxone
- B. Piperacillin
- C. Vancomycin (Correct Answer)
- D. Aztreonam
Food Allergies Explanation: ***Vancomycin***- **Vancomycin** is a glycopeptide antibiotic that is **structurally unrelated to penicillin**, with no cross-reactivity in penicillin-allergic patients [2].- It has **excellent activity against Enterococcus species** and is the **preferred alternative for enterococcal endocarditis** in patients with penicillin allergy [1, 2].- Vancomycin provides reliable bactericidal activity against enterococci and is guideline-recommended for this indication in penicillin-allergic patients [1].*Aztreonam*- **Aztreonam** is a monobactam antibiotic with minimal cross-reactivity to penicillin allergies due to its unique beta-lactam structure.- However, aztreonam has **NO activity against Gram-positive organisms**, including Enterococcus species.- It would be **completely ineffective** for treating enterococcal endocarditis despite being safe in penicillin allergy.*Ceftriaxone*- **Ceftriaxone** is a third-generation cephalosporin that shares the beta-lactam ring structure with penicillins.- There is approximately **1-3% cross-reactivity risk** in patients with non-severe penicillin allergy, and up to 10% in those with severe reactions [1].- Given this patient's history of rash and swelling, ceftriaxone carries **unacceptable cross-reactivity risk** [1].*Piperacillin*- **Piperacillin** is an extended-spectrum penicillin antibiotic, belonging to the same drug class as penicillin [1].- It is **absolutely contraindicated** in penicillin-allergic patients due to identical allergenic epitopes [1].- Administration would carry a **high risk of severe allergic reaction**, including potential anaphylaxis [1].
Food Allergies Indian Medical PG Question 6: Drug of choice for Enterococcus infection in a patient allergic to penicillin?
- A. Streptomycin
- B. Cephalosporin
- C. Vancomycin (Correct Answer)
- D. Rifampicin
Food Allergies Explanation: ***Vancomycin***
- **Vancomycin** is a glycopeptide antibiotic that is effective against **Gram-positive bacteria**, including *Enterococcus*, especially in patients with a **penicillin allergy**.
- It inhibits **cell wall synthesis** by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors, a different mechanism from penicillins.
*Streptomycin*
- **Streptomycin** is an aminoglycoside that inhibits **protein synthesis** and is primarily used in **combination therapy** for serious *Enterococcal* infections, but typically alongside a cell-wall active agent (like penicillin or vancomycin) for synergistic killing in endocarditis or other severe infections.
- It is not usually recommended as a **monotherapy** for *Enterococcus*, especially in the context of penicillin allergy, as it doesn't provide bactericidal activity on its own against all enterococcal strains.
*Cephalosporin*
- **Cephalosporins** are **not active** against *Enterococcus spp.* as these bacteria intrinsically lack the **penicillin-binding proteins (PBPs)** that cephalosporins target effectively.
- This **intrinsic resistance** makes cephalosporins an inappropriate choice for treating *Enterococcal* infections, regardless of penicillin allergy status.
*Rifampicin*
- **Rifampicin** is an antibiotic primarily used for **Mycobacterial infections** (e.g., tuberculosis) and some **Staphylococcal infections**, often in combination to prevent resistance.
- It has **poor activity** against *Enterococcus* and is not a recommended treatment for *Enterococcal* infections.
Food Allergies Indian Medical PG Question 7: What is a characteristic feature of Systemic Juvenile Idiopathic Arthritis?
- A. Uveitis is a feature
- B. It occurs after 16 years of age
- C. NSAIDs are contraindicated
- D. RA factor is negative (Correct Answer)
Food Allergies Explanation: ### Explanation
**Systemic Juvenile Idiopathic Arthritis (sJIA)**, also known as Still’s disease, is a unique subtype of JIA characterized by prominent extra-articular features.
**Why the correct answer is right:**
In sJIA, the **Rheumatoid Factor (RF) is characteristically negative**. Unlike the polyarticular subtype (which can be RF positive), sJIA is considered an autoinflammatory disease rather than a classic autoimmune disease. Diagnosis is clinical, based on the presence of arthritis in one or more joints associated with (or preceded by) a fever of at least 2 weeks' duration that is daily ("quotidian") for at least 3 days, accompanied by features like an evanescent salmon-pink rash, lymphadenopathy, or serositis.
**Analysis of Incorrect Options:**
* **A. Uveitis is a feature:** This is incorrect for sJIA. Chronic anterior uveitis is a classic complication of **Oligoarticular JIA** (especially if ANA positive). Uveitis is very rare in the systemic subtype.
* **B. It occurs after 16 years of age:** By definition, JIA must have an onset **before the age of 16**. If similar symptoms occur after 16, it is termed Adult-Onset Still’s Disease (AOSD).
* **C. NSAIDs are contraindicated:** This is false. NSAIDs are often the **first-line** symptomatic treatment for pain and fever in JIA, though systemic steroids or biologics (IL-1 and IL-6 inhibitors) are usually required for definitive control.
**High-Yield Clinical Pearls for NEET-PG:**
* **Fever Pattern:** Classic "Quotidian" fever (spikes once daily, usually in the evening, returning to baseline).
* **Laboratory Markers:** Marked leukocytosis, thrombocytosis, and highly elevated ESR/CRP.
* **Ferritin:** Extremely high ferritin levels are common and can signal the onset of **Macrophage Activation Syndrome (MAS)**, a life-threatening complication of sJIA.
* **Biologics of Choice:** Tocilizumab (IL-6 inhibitor) and Anakinra/Canakinumab (IL-1 inhibitors).
Food Allergies Indian Medical PG Question 8: A patient presents with thrombocytopenia, eczema, and recurrent infections. What is the most probable diagnosis?
- A. Wiskott Aldrich syndrome (Correct Answer)
- B. A beta gammaglobulinemia
- C. Chediak Higashi syndrome
- D. Lazy leukocyte syndrome
Food Allergies Explanation: **Explanation:**
The classic triad of **thrombocytopenia, eczema, and recurrent infections** is the hallmark presentation of **Wiskott-Aldrich Syndrome (WAS)**.
1. **Why A is Correct:** WAS is an X-linked recessive disorder caused by a mutation in the *WASp* gene, which leads to defects in the actin cytoskeleton of hematopoietic cells. This results in:
* **Thrombocytopenia:** Characteristically presents with **micro-platelets** (small size), leading to bleeding tendencies (e.g., petechiae, melena).
* **Eczema:** Typically develops within the first year of life.
* **Immunodeficiency:** Defects in both T-cells and B-cells lead to recurrent infections with encapsulated bacteria and opportunistic pathogens.
2. **Why the others are Incorrect:**
* **B. Agammaglobulinemia (Bruton’s):** Presents with recurrent pyogenic infections due to B-cell deficiency, but lacks thrombocytopenia and eczema.
* **C. Chediak-Higashi Syndrome:** Characterized by **oculocutaneous albinism**, giant cytoplasmic granules in neutrophils, and peripheral neuropathy.
* **D. Lazy Leukocyte Syndrome:** A defect in neutrophil chemotaxis and mobility; patients have neutropenia but not the classic triad of WAS.
**High-Yield Clinical Pearls for NEET-PG:**
* **Inheritance:** X-linked Recessive (mostly males).
* **Lab Finding:** Low IgM, normal/high IgA and IgE, and **small-sized platelets** (pathognomonic).
* **Complications:** High risk of **autoimmune hemolytic anemia** and **B-cell lymphomas**.
* **Treatment:** Hematopoietic stem cell transplant (HSCT) is the definitive cure.
Food Allergies Indian Medical PG Question 9: A child presents with delayed separation of the umbilical cord, leukocytosis, Down syndrome, and recurrent infections. What is the most likely diagnosis?
- A. Leukocyte Adhesion Deficiency (Correct Answer)
- B. Neonatal Sepsis
- C. Histiocytosis-X
- D. All of the above
Food Allergies Explanation: ### Explanation
**Correct Option: A. Leukocyte Adhesion Deficiency (LAD)**
**Why it is correct:**
Leukocyte Adhesion Deficiency (Type 1) is a primary immunodeficiency caused by a defect in the **CD18 subunit of $\beta_2$-integrins**. This defect prevents neutrophils from adhering to the vascular endothelium and migrating into tissues (diapedesis).
* **Delayed separation of the umbilical cord:** This is the classic hallmark of LAD. Normally, neutrophils infiltrate the cord stump to facilitate its detachment; in LAD, the absence of neutrophils at the site leads to delayed separation (often >30 days).
* **Leukocytosis:** Because neutrophils cannot leave the bloodstream to enter tissues, they accumulate in the blood, leading to persistent, marked neutrophilic leukocytosis.
* **Recurrent Infections:** Patients suffer from skin and mucosal infections (e.g., omphalitis, periodontitis) characterized by a **lack of pus formation** despite high white cell counts.
* **Association:** While not a primary feature, LAD has been documented in case reports involving children with Down syndrome.
**Why other options are incorrect:**
* **B. Neonatal Sepsis:** While sepsis causes leukocytosis and infections, it does not explain the specific anatomical delay in umbilical cord separation.
* **C. Histiocytosis-X (Langerhans Cell Histiocytosis):** This typically presents with seborrheic-like skin rashes, lytic bone lesions, and hepatosplenomegaly, rather than a specific defect in cord separation or integrin function.
**High-Yield Clinical Pearls for NEET-PG:**
* **LAD Type 1:** Defect in **CD18** (Integrins).
* **LAD Type 2:** Defect in **Sialyl-Lewis X** (Selectins); presents with short stature and intellectual disability.
* **Key Triad:** Delayed cord separation + Recurrent "cold" infections (no pus) + Extreme neutrophilia.
* **Diagnosis:** Confirmed by **Flow Cytometry** showing decreased expression of CD11/CD18.
Food Allergies Indian Medical PG Question 10: Which of the following is a feature of Henoch-Schönlein purpura?
- A. Palpable purpura and arthralgia (Correct Answer)
- B. Palpable purpura
- C. Occurs only in elderly persons
- D. Thrombocytopenia
Food Allergies Explanation: **Explanation:**
**Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**, is the most common systemic vasculitis in children. It is a small-vessel vasculitis characterized by the deposition of IgA-dominant immune complexes.
1. **Why Option A is correct:** The classic clinical tetrad of HSP includes **palpable purpura** (without thrombocytopenia), **arthralgia/arthritis**, abdominal pain, and renal disease (hematuria). Palpable purpura is the hallmark finding, typically distributed over the buttocks and lower extremities. Arthralgia occurs in about 75% of cases, most commonly affecting the knees and ankles. Therefore, Option A represents the most comprehensive clinical feature among the choices.
2. **Why other options are incorrect:**
* **Option B:** While palpable purpura is a feature, Option A is a more complete description of the systemic nature of the disease.
* **Option C:** HSP is primarily a **pediatric disease**, with a peak incidence between ages 3 and 10 years. It is rare in infants and less common in adults.
* **Option D:** A defining feature of HSP is that it is a **non-thrombocytopenic purpura**. The platelet count is characteristically normal or even elevated (thrombocytosis). This distinguishes it from Immune Thrombocytopenic Purpura (ITP).
**Clinical Pearls for NEET-PG:**
* **Preceding Event:** Often follows an Upper Respiratory Tract Infection (URTI), specifically Group A *Streptococcus*.
* **Renal Involvement:** The most serious long-term complication is **HSP nephritis**, which is histologically identical to IgA Nephropathy (Berger’s disease).
* **Gastrointestinal:** Intussusception (typically ileo-ileal) is a known surgical complication.
* **Diagnosis:** Primarily clinical; skin biopsy shows **leukocytoclastic vasculitis** with IgA deposition on immunofluorescence.
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