Allergic Contact Dermatitis in Workplace — MCQs
A 32 year old man presents with a 3-month history of weight loss, night sweats, a productive cough with blood-tinged sputum, anorexia, general malaise, and a low grade fever. A PPD skin test shows > 10 mm of induration. If the area of induration were biopsied, which of the following type of reactive cells would be found?
A construction worker came to the OPD complaining of white fingers. He has been working in the cement and concrete industry and has been working on heavy machinery drills, wood, and furniture polishing for 20 years. What is the most likely etiology for this condition?
Preplacement examination in dye industry includes all of the following except -
A woman comes to psychiatrist with history of spending a lot of time in washing her hands. She is distressed about it but says that she is not able to stop washing. This has started to affect her social life as well. What is the best mode of treatment for her?
Most common precipitant of contact dermatitis is?
What type of hypersensitivity reaction is primarily associated with allergic rhinitis?
A man presents with a rash on his flank with itching for the past 2 weeks. The patient has tried several over-the-counter medications, including lotrimin and hydrocortisone, without any improvement. In physical examination, the rash is seen on his palms and the sole of one foot, but no oral lesions are found. What is the likely diagnosis?
A hospital implements a policy to reduce occupational hand dermatitis in healthcare workers. They propose: (A) Switching from latex to nitrile gloves, (B) Installing alcohol-based hand rub dispensers, (C) Providing emollients, (D) Reducing glove use frequency. Synthesize the best evidence-based strategy.
Evaluate the following scenario: A 38-year-old worker in an electronics manufacturing unit develops hand dermatitis. Initial patch testing shows multiple positive reactions to metals (nickel, cobalt, chromium). Despite workplace modifications and protective equipment, the dermatitis persists. Re-evaluation reveals positive patch test to colophony. What is the best strategic approach?
A 45-year-old florist develops dermatitis on hands and forearms. Patch testing shows positive reactions to Compositae mix and sesquiterpene lactones. She also has scattered airborne pattern dermatitis on face and neck. Analyzing this pattern, what is the most likely diagnosis?
Allergic Contact Dermatitis in Workplace Indian Medical PG Practice Questions and MCQs
Question 1: A 32 year old man presents with a 3-month history of weight loss, night sweats, a productive cough with blood-tinged sputum, anorexia, general malaise, and a low grade fever. A PPD skin test shows > 10 mm of induration. If the area of induration were biopsied, which of the following type of reactive cells would be found?
- A. Eosinophil
- B. T lymphocyte (Correct Answer)
- C. B lymphocyte
- D. Mast cell
Explanation: ***T lymphocyte*** - The clinical picture (weight loss, night sweats, productive cough with blood-tinged sputum, positive PPD) is highly suggestive of **tuberculosis**, a **Type IV hypersensitivity reaction** [1], [2]. - **Type IV hypersensitivity reactions** are cell-mediated, involving the activation of **T lymphocytes**, which migrate to the site of antigen exposure (like a PPD test site or a tuberculous granuloma) and release cytokines, leading to induration and inflammation [1], [2]. *Eosinophil* - **Eosinophils** are primarily involved in allergic reactions and defense against parasitic infections [3]. - They are not the predominant reactive cells in a **Type IV hypersensitivity** response like that seen in tuberculosis [1]. *Mast cell* - **Mast cells** play a critical role in immediate hypersensitivity reactions (Type I), releasing histamine and other mediators [4]. - They are not the primary cells involved in the delayed-type hypersensitivity response elicited by tuberculin purified protein derivative (PPD) [2]. *B lymphocyte* - **B lymphocytes** are responsible for humoral immunity by producing antibodies [3]. - While they contribute to overall immune responses, they are not the main effector cells in a cell-mediated **Type IV hypersensitivity reaction** characteristic of a positive PPD test [1], [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 173-174. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 218. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 195-196. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 208-210.
Question 2: A construction worker came to the OPD complaining of white fingers. He has been working in the cement and concrete industry and has been working on heavy machinery drills, wood, and furniture polishing for 20 years. What is the most likely etiology for this condition?
- A. Candidal infection of the fingers due to continuous exposure to water
- B. Exposure to thinners and paints
- C. Continuous exposure to cement and concrete
- D. Continuous exposure to drills and machines (Correct Answer)
Explanation: ***Continuous exposure to drills and machines*** - The use of **heavy machinery drills** subjects the hands to **vibration**, which is a well-known cause of **Raynaud's phenomenon**, presenting as "white fingers" due to **vasospasm**. - This condition, often referred to as **vibration white finger**, is a common occupational hazard for workers using vibratory tools over long periods. *Candidal infection of the fingers due to continuous exposure to water* - While prolonged exposure to moisture can cause **Candidal infections** (e.g., paronychia), this typically presents as **redness, swelling, and pain** around the nails or skin, not the characteristic "white fingers" of Raynaud's. - White fingers due to candidiasis are not a primary manifestation and lack the **vasospastic component** seen with vibration exposure. *Exposure to thinners and paints* - Exposure to chemicals like **thinners and paints** can cause **irritant or allergic contact dermatitis**, leading to redness, itching, and skin lesions. - However, direct exposure to these substances is not typically associated with the sudden, episodic **blanching of fingers** characteristic of Raynaud's phenomenon. *Continuous exposure to cement and concrete* - **Cement and concrete** exposure often leads to **irritant or allergic contact dermatitis** due to the alkaline nature of cement, causing dryness, cracking, and eczema. - This type of exposure does not directly cause the **vasospastic episodes** that result in "white fingers."
Question 3: Preplacement examination in dye industry includes all of the following except -
- A. Precancerous lesion
- B. Asthma
- C. Anemia (Correct Answer)
- D. Dermatitis
Explanation: ***Anemia*** - While general health screening might include checking for **anemia**, it's not a primary focus or specific risk factor directly associated with chronic dye exposure that would necessitate targeted pre-placement screening in the same way as conditions directly linked to common dye industry hazards. - Anemia is typically identified through a **complete blood count (CBC)**, which is a broad health marker rather than a specific occupational health concern in this context. *Precancerous lesion* - Exposure to certain **aromatic amines** and other chemicals used in the dye industry can increase the risk of developing **bladder cancer**. - Screening for precancerous lesions, especially in the **urinary tract**, is crucial given the occupational exposure to carcinogens. *Asthma* - Workers in the dye industry can be exposed to various **dyes, intermediates, and solvents** that are known **respiratory sensitizers and irritants**. - This exposure can lead to the development of **occupational asthma** or exacerbate pre-existing asthma. *Dermatitis* - Many chemicals and dyes handled in the industry are potent **skin irritants or sensitizers**, leading to **contact dermatitis** (irritant or allergic). - Pre-placement examination would assess skin health and potential susceptibility to prevent occupational skin diseases.
Question 4: A woman comes to psychiatrist with history of spending a lot of time in washing her hands. She is distressed about it but says that she is not able to stop washing. This has started to affect her social life as well. What is the best mode of treatment for her?
- A. Exposure and response prevention (Correct Answer)
- B. Systematic desensitization
- C. Cognitive behavioral therapy
- D. Pharmacological agents
Explanation: ***Exposure and response prevention*** - **Exposure and response prevention (ERP)** is the **most specific and evidence-based** psychotherapy for **obsessive-compulsive disorder (OCD)**. - It is a specialized form of **Cognitive Behavioral Therapy (CBT)** that directly targets OCD by gradually exposing the individual to situations or objects that trigger their obsessions (e.g., dirt) and then preventing them from performing their compulsive rituals (e.g., handwashing). - **ERP is considered the gold standard psychotherapy** for OCD with the strongest evidence base, making it the **best** (most specific) answer. *Systematic desensitization* - This technique is primarily used for **specific phobias** and involves pairing relaxation techniques with gradual exposure to feared stimuli. - While it involves exposure, it does **not address the response prevention component** critical for treating compulsive rituals in OCD. - Less effective than ERP for OCD specifically. *Cognitive behavioral therapy* - **CBT is also a correct treatment** for OCD, as ERP is delivered within a CBT framework. - However, when answering "best mode of treatment," **ERP is the more specific answer** as it identifies the particular CBT technique with the strongest evidence for OCD. - Standard CBT without the specific ERP component (focusing only on cognitive restructuring) would be less effective than ERP for compulsive behaviors. *Pharmacological agents* - **SSRIs** (particularly high-dose) are first-line pharmacological treatment for OCD and often used in combination with ERP. - However, **psychotherapy with ERP** is generally considered the first-line treatment and can achieve significant long-term remission even as monotherapy. - The question asks for "mode of treatment" in a clinical context where behavioral intervention is being considered, making ERP the best answer.
Question 5: Most common precipitant of contact dermatitis is?
- A. Gold
- B. Silver
- C. Iron
- D. Nickel (Correct Answer)
Explanation: ***Nickel*** - **Nickel** is the most frequent cause of **allergic contact dermatitis**, commonly found in jewelry, belt buckles, and zippers. - Exposure leads to a **Type IV hypersensitivity reaction**, characterized by erythema, itching, and vesiculation. *Gold* - While gold can cause contact dermatitis, it is **far less common** than nickel allergy. - Reactions to gold are often seen with prolonged skin contact, such as with jewelry. *Silver* - **Silver** is a **rare cause** of allergic contact dermatitis. - Allergic reactions to silver are typically observed in individuals with extensive exposure, such as jewelers. *Iron* - **Iron** is **not a common precipitant** of contact dermatitis. - Allergic reactions to iron are exceedingly rare, as iron is an essential element found naturally in the body.
Question 6: What type of hypersensitivity reaction is primarily associated with allergic rhinitis?
- A. Type I hypersensitivity reaction (Correct Answer)
- B. Type IV hypersensitivity reaction
- C. Type II hypersensitivity reaction
- D. Type III hypersensitivity reaction
Explanation: ***Type I hypersensitivity reaction*** - Allergic rhinitis is a classic example of a **Type I hypersensitivity reaction**, mediated primarily by **IgE antibodies** [1]. - Exposure to allergens triggers mast cell degranulation, releasing **histamine** and other mediators that cause symptoms like sneezing, rhinorrhea, and nasal congestion [2]. *Type II* - **Type II hypersensitivity reactions** involve **IgG or IgM antibodies** targeting antigens on cell surfaces or extracellular matrix, leading to cell lysis or dysfunction [4]. - Examples include **hemolytic anemia** and **Goodpasture syndrome**, which are distinct from allergic rhinitis. *Type III* - **Type III hypersensitivity reactions** involve the formation of **immune complexes** (antigen-antibody complexes) that deposit in tissues, leading to inflammation [4]. - Conditions like **serum sickness** and **lupus nephritis** are examples, not allergic rhinitis. *Type IV* - **Type IV hypersensitivity reactions** are **delayed-type hypersensitivity** reactions mediated by **T lymphocytes**, not antibodies. - Examples include **contact dermatitis** and the **tuberculin skin test**, which manifest much later after antigen exposure [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 210. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 211-212. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 171-172. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 208-210.
Question 7: A man presents with a rash on his flank with itching for the past 2 weeks. The patient has tried several over-the-counter medications, including lotrimin and hydrocortisone, without any improvement. In physical examination, the rash is seen on his palms and the sole of one foot, but no oral lesions are found. What is the likely diagnosis?
- A. Tinea corporis
- B. Pityriasis rosea
- C. Secondary syphilis (Correct Answer)
- D. Contact dermatitis
Explanation: ***Secondary syphilis*** - The rash presenting on the **palms and soles** is highly characteristic of **secondary syphilis**, which helps differentiate it from many other dermatological conditions. - The lack of improvement with antifungal (Lotrimin) and corticosteroid (hydrocortisone) treatments further supports a diagnosis other than a fungal infection or inflammatory dermatitis. *Tinea corporis* - This fungal infection typically presents as an **annular (ring-shaped) rash** with central clearing and well-demarcated borders, often on the trunk or limbs. - It would likely show some improvement, even if partial, with **Lotrimin (an antifungal medication)**, which is not the case here. *Pityriasis rosea* - This condition is characterized by an initial **"herald patch"** followed by smaller, oval, pinkish-red patches that often align along skin cleavage lines in a **"Christmas tree" pattern** on the trunk. - It typically spares the palms and soles, which are involved in this patient's presentation. *Contact dermatitis* - This is an inflammatory skin reaction due to contact with an allergen or irritant, presenting as **pruritic (itchy) erythematous (red) patches, possibly with vesicles or bullae**, limited to exposed areas. - While hydrocortisone might offer some relief, the presentation on palms and soles without clear exposure and the lack of response to treatment make it less likely.
Question 8: A hospital implements a policy to reduce occupational hand dermatitis in healthcare workers. They propose: (A) Switching from latex to nitrile gloves, (B) Installing alcohol-based hand rub dispensers, (C) Providing emollients, (D) Reducing glove use frequency. Synthesize the best evidence-based strategy.
- A. Implement all four measures as glove occlusion worsens dermatitis
- B. Implement only A and C to reduce costs
- C. Implement A, B, and C; avoiding D as it compromises infection control (Correct Answer)
- D. Focus only on B and C as glove material is not the primary issue
Explanation: ***Implement A, B, and C; avoiding D as it compromises infection control*** - Combining **non-latex (nitrile) gloves**, **alcohol-based rubs**, and **emollients** is the evidence-based triad for reducing **irritant contact dermatitis** and **Type I hypersensitivity** while maintaining skin barrier integrity. - Reducing the frequency of glove use (D) is an inappropriate strategy because it directly **compromises infection control** and increases the risk of **bloodborne pathogen exposure**. *Implement all four measures as glove occlusion worsens dermatitis* - While **glove occlusion** can contribute to dermatitis, intentionally reducing glove use (D) violates standard precautions for **patient and provider safety**. - The goal is to optimize the **type of glove** and **skin care regimen** rather than sacrificing necessary barrier protection. *Implement only A and C to reduce costs* - Excluding **alcohol-based hand rubs (B)** is counterproductive, as frequent washing with water and detergent is actually more **irritating to the skin** than alcohol rubs. - A strategy based solely on cost ignores the clinical evidence that **barrier creams and emollients** work best when integrated with less damaging hand hygiene methods. *Focus only on B and C as glove material is not the primary issue* - This ignores the significant prevalence of **latex allergy** and sensitivity to **accelerants** found in standard gloves, which contributes to **allergic contact dermatitis**. - Switching to **nitrile gloves (A)** is a critical step in a comprehensive occupational policy to eliminate **Type I latex hypersensitivity** risks.
Question 9: Evaluate the following scenario: A 38-year-old worker in an electronics manufacturing unit develops hand dermatitis. Initial patch testing shows multiple positive reactions to metals (nickel, cobalt, chromium). Despite workplace modifications and protective equipment, the dermatitis persists. Re-evaluation reveals positive patch test to colophony. What is the best strategic approach?
- A. The persistent dermatitis indicates evolution to chronic actinic dermatitis
- B. Colophony in soldering flux is the relevant occupational allergen; the metal sensitivities may be cross-reactions or co-sensitization (Correct Answer)
- C. All positive reactions are equally relevant and complete job change is mandatory
- D. The multiple sensitivities indicate systemic contact dermatitis requiring systemic therapy
Explanation: ***Colophony in soldering flux is the relevant occupational allergen; the metal sensitivities may be cross-reactions or co-sensitization*** - **Colophony** (rosin) is a frequent sensitizer in the **electronics industry**, where it is used as a flux in **soldering** to prevent oxidation. - Persistence of symptoms despite metal avoidance highlights the importance of identifying the **relevant allergen** versus incidental background sensitivity or **cross-reactivity**. *The persistent dermatitis indicates evolution to chronic actinic dermatitis* - **Chronic actinic dermatitis** is a photosensitive condition and is not a typical progression of **allergic contact dermatitis** caused by chemical exposure. - There is no clinical evidence of **photosensitivity** or UV-induced lesions mentioned in this occupational scenario. *All positive reactions are equally relevant and complete job change is mandatory* - Not all positive **patch tests** translate to clinical relevance; some may represent **excited skin syndrome** or past, non-relevant exposures. - A **job change** is a last resort; the management focus should be on specific **allergen substitution** or improved engineering controls for the **colophony** exposure. *The multiple sensitivities indicate systemic contact dermatitis requiring systemic therapy* - **Systemic contact dermatitis** occurs when an allergen is medicinally or dietarily ingested, not through **occupational cutaneous contact**. - Primary management involves **allergen avoidance** and topical therapists rather than initiating long-term **systemic immunosuppression** for manageable contactants.
Question 10: A 45-year-old florist develops dermatitis on hands and forearms. Patch testing shows positive reactions to Compositae mix and sesquiterpene lactones. She also has scattered airborne pattern dermatitis on face and neck. Analyzing this pattern, what is the most likely diagnosis?
- A. Irritant contact dermatitis from fertilizers
- B. Phototoxic dermatitis from plant handling
- C. Combined contact and airborne contact dermatitis from Compositae family plants (Correct Answer)
- D. Atopic dermatitis exacerbated by occupation
Explanation: ***Combined contact and airborne contact dermatitis from Compositae family plants*** - The patient exhibits classic **occupational sensitization** to **sesquiterpene lactones**, which are the primary allergens found in the **Compositae (Asteraceae)** plant family common in floristry. - The dual presentation includes **direct contact dermatitis** on the hands/forearms and **airborne contact dermatitis** on the face and neck caused by aerosolized plant particles or pollen. *Irritant contact dermatitis from fertilizers* - This typically presents as a localized reaction to harsh chemicals and would not explain the specific **positive patch test** to sesquiterpene lactones. - **Irritant dermatitis** usually lacks the distinct **airborne pattern** on the face and neck unless there is significant volatile exposure, which is less common with standard solid fertilizers. *Phototoxic dermatitis from plant handling* - Phototoxic reactions (like **phytophotodermatitis**) usually cause a **streaky, blistering** rash limited to sun-exposed areas where the plant sap made direct contact. - It is primarily triggered by **furocoumarins** (e.g., in limes or celery) rather than the sesquiterpene lactones identified in this patient's diagnostic testing. *Atopic dermatitis exacerbated by occupation* - While occupational stress can flare atopy, **atopic dermatitis** typically involves flexural surfaces and has a chronic, relapsing history rather than a specific **airborne distribution**. - The **positive patch test** for specific plant allergens strongly indicates a **Type IV hypersensitivity** (allergic contact) rather than a primary atopic constitutional skin barrier defect.
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