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Question 1General dermatology: inflammatory, papulosquamous and eczematous disorders

Removal of a scale from an active psoriatic plaque leaves a moist surface with pinpoint bleeding. What is this clinical sign called?

  1. Darier sign
  2. Auspitz sign Correct answer.
  3. Nikolsky sign
  4. Koebner phenomenon

Explanation

Auspitz sign refers to pinpoint capillary bleeding when psoriatic scale is lifted, reflecting elongated, tortuous dermal papillae close to the surface. Koebner phenomenon is the appearance of lesions at sites of trauma, Nikolsky sign is epidermal separation on friction, and Darier sign is urtication of a lesion on rubbing.

Question 2General dermatology: inflammatory, papulosquamous and eczematous disorders

In pityriasis rosea, which feature typically appears several days to two weeks before the generalized eruption?

  1. Nail plate pitting
  2. Diffuse palmoplantar scaling
  3. A single herald patch Correct answer.
  4. Erosive oral ulcers

Explanation

Pityriasis rosea classically begins with a herald patch, a solitary oval salmon-colored scaly plaque, followed by a secondary eruption along skin cleavage lines. Palmar, mucosal and nail changes are not part of the typical picture.

Question 3General dermatology: inflammatory, papulosquamous and eczematous disorders

Fine, lacy white lines seen on the surface of cutaneous and oral lichen planus lesions are known as what?

  1. Wickham striae Correct answer.
  2. Munro microabscesses
  3. Civatte bodies
  4. Koebner lines

Explanation

Wickham striae are the reticulated white streaks produced by hypergranulosis and orthokeratosis in lichen planus. They are best seen on buccal mucosa and on the surface of violaceous, flat-topped papules.

Question 4General dermatology: inflammatory, papulosquamous and eczematous disorders

Seborrheic dermatitis is most strongly associated with overgrowth of which organism?

  1. Dermatophyte molds
  2. Candida albicans
  3. Corynebacterium minutissimum
  4. Malassezia yeasts Correct answer.

Explanation

Malassezia species are lipophilic yeasts that colonize sebaceous areas and provoke the inflammatory response of seborrheic dermatitis, which is why azole antifungals are effective. The condition favors the scalp, eyebrows, nasolabial folds and central chest.

Question 5General dermatology: inflammatory, papulosquamous and eczematous disorders

Which symptom is regarded as the cardinal feature of atopic dermatitis at every age?

  1. Burning pain
  2. Pruritus Correct answer.
  3. Nail dystrophy
  4. Widespread scaling

Explanation

Itch is the essential feature of atopic dermatitis and is required for the diagnosis; excoriations, lichenification and sleep disturbance all follow from it. Scaling and nail changes are variable secondary findings, and pain is not characteristic.

Question 6General dermatology: inflammatory, papulosquamous and eczematous disorders

A 12-year-old develops a sudden crop of small drop-like scaly papules on the trunk two weeks after a sore throat. Which trigger is most likely?

  1. Recent herpes simplex infection
  2. HIV seroconversion
  3. Helicobacter pylori gastritis
  4. Streptococcal pharyngitis Correct answer.

Explanation

Guttate psoriasis is classically precipitated by group A streptococcal pharyngitis with a latency of one to three weeks. Lesions are 2 to 10 mm teardrop-shaped papules with fine scale, distributed mainly on the trunk and proximal limbs.

Question 7General dermatology: inflammatory, papulosquamous and eczematous disorders

An infant has greasy yellow scales on the scalp with mild erythema but no lesions elsewhere. What is the most likely diagnosis?

  1. Tinea capitis infection
  2. Atopic dermatitis of infancy
  3. Plaque psoriasis vulgaris
  4. Seborrheic dermatitis Correct answer.

Explanation

Infantile seborrheic dermatitis, often called cradle cap, produces adherent greasy yellow scale on the scalp of well infants, usually within the first months of life. Atopic dermatitis favors the cheeks and extensor surfaces and is intensely pruritic, while tinea capitis usually shows alopecia and broken hairs.

Question 8General dermatology: inflammatory, papulosquamous and eczematous disorders

Allergic contact dermatitis is mediated by which type of hypersensitivity reaction?

  1. Type IV delayed hypersensitivity Correct answer.
  2. Type I immediate hypersensitivity
  3. Type III immune-complex hypersensitivity
  4. Type II antibody-mediated hypersensitivity

Explanation

Allergic contact dermatitis is a type IV cell-mediated reaction in which hapten-specific T lymphocytes are recruited to the skin 24 to 72 hours after re-exposure. This is why patch testing requires removal of patches at 48 hours with a delayed reading.

Question 9General dermatology: inflammatory, papulosquamous and eczematous disorders

A patient has limited plaque psoriasis confined to both elbows. What is the most appropriate initial treatment?

  1. Whole-body narrowband UVB
  2. Systemic ciclosporin
  3. Topical corticosteroid Correct answer.
  4. Oral methotrexate

Explanation

Limited plaque psoriasis is managed first with topical therapy, typically a corticosteroid with or without a vitamin D analogue. Phototherapy and systemic agents are reserved for extensive or refractory disease.

Question 10General dermatology: inflammatory, papulosquamous and eczematous disorders

Pitting of the nail plate in a patient with psoriasis indicates involvement of which structure?

  1. The nail matrix Correct answer.
  2. The nail fold
  3. The nail bed
  4. The hyponychium

Explanation

Nail pitting results from focal parakeratosis of the proximal nail matrix, so the defect is carried outwards in the plate. Nail bed involvement instead produces oil-drop discoloration and onycholysis.

Question 11General dermatology: inflammatory, papulosquamous and eczematous disorders

Deficiency of which epidermal structural protein, encoded by the FLG gene, predisposes to atopic dermatitis and ichthyosis vulgaris?

  1. Loricrin
  2. Involucrin
  3. Collagen XVII
  4. Filaggrin Correct answer.

Explanation

Filaggrin aggregates keratin filaments and contributes to the cornified envelope and natural moisturizing factor; loss-of-function variants impair the barrier and are strong risk factors for atopic dermatitis. Barrier failure then permits allergen and irritant penetration that drives inflammation.

Question 12General dermatology: inflammatory, papulosquamous and eczematous disorders

A child with atopic dermatitis develops clustered monomorphic dome-shaped vesicles with punched-out erosions and fever. What is the most appropriate immediate action?

  1. Prescribe a topical corticosteroid under occlusion
  2. Start systemic aciclovir urgently Correct answer.
  3. Apply topical tacrolimus and review in one week
  4. Start oral flucloxacillin

Explanation

The picture is eczema herpeticum, a disseminated herpes simplex infection that can progress to viraemia and keratoconjunctivitis. It requires prompt systemic antiviral therapy, and topical calcineurin inhibitors or occlusion should be avoided during active infection.

Question 13General dermatology: inflammatory, papulosquamous and eczematous disorders

An older man with very dry skin has several coin-shaped, oozing, crusted plaques on the shins. What is the most likely diagnosis?

  1. Pityriasis rosea
  2. Nummular eczema Correct answer.
  3. Tinea corporis
  4. Psoriasis vulgaris

Explanation

Nummular eczema produces well-defined coin-shaped eczematous plaques, typically on the lower legs of older patients with dry skin. Exudation and crusting reflect the acute eczematous process, and treatment centers on emollients and topical corticosteroids.

Question 14General dermatology: inflammatory, papulosquamous and eczematous disorders

Deep-seated tapioca-like vesicles on the palms and the lateral aspects of the fingers are characteristic of which condition?

  1. Lichen planus
  2. Palmoplantar psoriasis
  3. Dyshidrotic eczema Correct answer.
  4. Tinea manuum

Explanation

Dyshidrotic eczema, also called pompholyx, produces intensely itchy deep saccular vesicles on the palms, soles and sides of digits. Palmoplantar psoriasis instead shows hyperkeratotic fissured plaques, and tinea manuum has a dry, powdery, one-hand scale.

Question 15General dermatology: inflammatory, papulosquamous and eczematous disorders

An obese 70-year-old with long-standing varicose veins has bilateral itchy, scaly, hyperpigmented plaques around the ankles. Which underlying process explains this eruption?

  1. Reduced sweating
  2. Chronic arterial insufficiency
  3. Venous hypertension Correct answer.
  4. Lymphatic filariasis

Explanation

Stasis dermatitis results from chronic venous hypertension, which causes capillary leakage, haemosiderin deposition and a chronic eczematous response around the ankles. Leg elevation, compression and emollients are the mainstays of management.

Question 16General dermatology: inflammatory, papulosquamous and eczematous disorders

Which treatment is first-line for symptomatic cutaneous lichen planus limited to a small area?

  1. Potent topical corticosteroid Correct answer.
  2. Narrowband UVB phototherapy
  3. Oral prednisolone at immunosuppressive doses
  4. Systemic retinoids

Explanation

Localized cutaneous lichen planus responds well to potent topical corticosteroids, often under occlusion or as intralesional injections for thick lesions. Systemic therapy and phototherapy are reserved for widespread, erosive or refractory disease.

Question 17General dermatology: inflammatory, papulosquamous and eczematous disorders

Pityriasis rosea has been most consistently linked to reactivation of which virus?

  1. Human papillomavirus infection
  2. Cytomegalovirus reactivation
  3. Epstein-Barr virus reactivation
  4. Human herpesvirus 6 Correct answer.

Explanation

Human herpesvirus 6 and, less often, HHV-7 have been detected in the lesional skin and blood of patients with pityriasis rosea, suggesting reactivation from latency. The eruption is self-limiting and usually resolves over six to eight weeks.

Question 18General dermatology: inflammatory, papulosquamous and eczematous disorders

Which musculoskeletal feature most favors psoriatic arthritis over rheumatoid arthritis?

  1. Subcutaneous rheumatoid nodules
  2. Positive rheumatoid factor
  3. Symmetrical small-joint synovitis
  4. Dactylitis and enthesitis Correct answer.

Explanation

Dactylitis (sausage digits) and enthesitis at insertions such as the Achilles tendon are hallmarks of psoriatic arthritis. Rheumatoid arthritis is typically a symmetrical small-joint synovitis with rheumatoid factor and nodules.

Question 19General dermatology: inflammatory, papulosquamous and eczematous disorders

Which statement best distinguishes irritant from allergic contact dermatitis?

  1. Depends on circulating immune complexes
  2. Requires prior hapten sensitization
  3. IgE-mediated mast cell activation
  4. Non-immune direct toxicity Correct answer.

Explanation

Irritant contact dermatitis results from direct cytotoxic damage to the epidermis and needs no prior sensitization, so it can occur on first exposure and is dose dependent. Allergic contact dermatitis requires prior sensitization to a hapten and is T-cell mediated.

Question 20General dermatology: inflammatory, papulosquamous and eczematous disorders

Erythroderma is conventionally defined as erythema and scaling involving at least what proportion of the body surface area?

  1. 50%
  2. 70%
  3. 90% Correct answer.
  4. 30%

Explanation

Erythroderma denotes generalized erythema with scale affecting at least 90% of the body surface. It can arise from psoriasis, eczema, drug reactions or cutaneous lymphoma and carries risks of fluid loss and hypothermia.

Question 21General dermatology: inflammatory, papulosquamous and eczematous disorders

Which finding in the stratum corneum on histology is characteristic of psoriasis?

  1. Civatte bodies
  2. Pautrier microabscesses
  3. Suprabasal acantholysis with clefting
  4. Munro microabscesses Correct answer.

Explanation

Munro microabscesses are focal collections of neutrophils within the parakeratotic stratum corneum of psoriatic plaques. They accompany regular acanthosis with thinning over dermal papillae and dilated capillary loops.

Question 22General dermatology: inflammatory, papulosquamous and eczematous disorders

Patients with erosive oral lichen planus need long-term follow-up chiefly because of an increased risk of which complication?

  1. Recurrent oral candidiasis
  2. Squamous cell carcinoma Correct answer.
  3. Angular cheilitis
  4. Dental caries

Explanation

Erosive and atrophic oral lichen planus carries a small but real risk of malignant transformation to squamous cell carcinoma, warranting periodic oral examination and biopsy of persistent change. Candida overgrowth may complicate the disease but is not the reason for long-term surveillance.

Question 23General dermatology: inflammatory, papulosquamous and eczematous disorders

Dupilumab improves atopic dermatitis by blocking which molecular target?

  1. The shared p40 subunit of IL-12 and IL-23
  2. Janus kinase 1 and 2
  3. The IL-5 receptor alpha subunit
  4. The IL-4 receptor alpha subunit Correct answer.

Explanation

Dupilumab is a monoclonal antibody against the IL-4 receptor alpha subunit, which is shared by the IL-4 and IL-13 receptors, thereby dampening type 2 inflammation. This differs from JAK inhibitors, which block intracellular cytokine signalling downstream of several receptors.

Question 24General dermatology: inflammatory, papulosquamous and eczematous disorders

Which finding on biopsy most favors a lichenoid drug eruption over idiopathic lichen planus?

  1. Lacy white lines on the buccal mucosa
  2. Intense itch with Koebner phenomenon
  3. Eosinophils on biopsy Correct answer.
  4. Grouped flat-topped violaceous papules

Explanation

Lichenoid drug eruptions tend to show parakeratosis, a deeper infiltrate and eosinophils, and they resolve after withdrawal of the culprit drug. Idiopathic lichen planus instead shows orthokeratosis, wedge-shaped hypergranulosis and a band-like lymphocytic infiltrate with Civatte bodies.

Question 25General dermatology: inflammatory, papulosquamous and eczematous disorders

A child develops orange-red scaly plaques with islands of sparing and waxy thickening of the palms and soles. Which diagnosis fits best?

  1. Seborrheic dermatitis
  2. Pityriasis rubra pilaris Correct answer.
  3. Lichen planus
  4. Generalized plaque psoriasis

Explanation

Pityriasis rubra pilaris produces orange-red follicular and confluent scaly plaques with characteristic islands of unaffected skin and waxy palmoplantar keratoderma. Psoriasis lacks the islands of sparing and usually shows silvery rather than orange-red scale.

Question 26General dermatology: inflammatory, papulosquamous and eczematous disorders

Pinpoint bleeding that appears after the scale is gently lifted from a psoriasis plaque is known as which sign?

  1. Koebner phenomenon
  2. Darier sign
  3. Auspitz sign Correct answer.
  4. Nikolsky sign

Explanation

The Auspitz sign reflects elongation of the dermal papillary capillaries, which lie close to the surface under a thinned suprapapillary plate; removing the scale exposes and ruptures them. It is a classic bedside clue to psoriasis.

Question 27General dermatology: inflammatory, papulosquamous and eczematous disorders

Overgrowth of which organism is most strongly implicated in the pathogenesis of seborrheic dermatitis?

  1. Malassezia species Correct answer.
  2. Dermatophyte fungi
  3. Candida albicans
  4. Propionibacterium acnes

Explanation

Malassezia yeasts are normal skin commensals, and seborrheic dermatitis is thought to represent an inflammatory host response to them in sebaceous-rich areas. This is why topical azole antifungals are effective.

Question 28General dermatology: inflammatory, papulosquamous and eczematous disorders

Fine white lacy lines visible on the surface of violaceous, flat-topped papules are termed which of the following?

  1. Beau lines
  2. Dennie-Morgan lines
  3. Pastia lines
  4. Wickham striae Correct answer.

Explanation

Wickham striae are a hallmark of lichen planus and are best seen on the wrists, ankles and oral mucosa, where they form a reticulated white pattern. They correspond histologically to focal hypergranulosis.

Question 29General dermatology: inflammatory, papulosquamous and eczematous disorders

In an infant younger than 6 months, which distribution of atopic dermatitis is most typical?

  1. Flexural creases of the antecubital and popliteal fossae
  2. Diaper area with satellite pustules
  3. Face and extensor surfaces Correct answer.
  4. Scalp only, with greasy yellow scales

Explanation

Infantile atopic dermatitis favours the cheeks, forehead and extensor limbs, often with oozing and crusting. The flexural pattern of the older child and adult usually develops later.

Question 30General dermatology: inflammatory, papulosquamous and eczematous disorders

Which medication is most likely to provoke a flare of pre-existing plaque psoriasis?

  1. Levothyroxine
  2. Amoxicillin
  3. Lisinopril
  4. Lithium carbonate Correct answer.

Explanation

Lithium is a well-recognised trigger for psoriasis and can also produce a psoriasiform drug eruption. Beta-blockers, antimalarials, interferon and rapid withdrawal of systemic corticosteroids are other classic precipitants.

Question 31General dermatology: inflammatory, papulosquamous and eczematous disorders

A 10-year-old with mild atopic dermatitis has a few small, slightly lichenified flexural plaques. Alongside regular emollients, which treatment is most appropriate first-line?

  1. Oral methotrexate
  2. Topical hydrocortisone 1% Correct answer.
  3. Narrowband UVB phototherapy
  4. Oral flucloxacillin

Explanation

Mild, localised atopic dermatitis is managed with emollients plus a low-potency topical corticosteroid, which controls inflammation while limiting risk of atrophy. Systemic agents and phototherapy are reserved for moderate-to-severe or refractory disease.

Question 32General dermatology: inflammatory, papulosquamous and eczematous disorders

An adult has greasy scaling of the scalp and eyebrows with mild erythema and no other skin findings. What is the most appropriate initial treatment?

  1. Ketoconazole shampoo Correct answer.
  2. Coal tar shampoo weekly
  3. Oral terbinafine
  4. Topical calcipotriol

Explanation

Topical azole shampoos reduce Malassezia colonisation and are first-line for scalp seborrheic dermatitis; they can be used intermittently for maintenance. Mild topical corticosteroids may be added for inflamed areas.

Question 33General dermatology: inflammatory, papulosquamous and eczematous disorders

A young adult develops symmetric target lesions on the hands and forearms about a week after a cold sore. What is the most likely diagnosis?

  1. Erythema multiforme Correct answer.
  2. Urticaria
  3. Pityriasis rosea
  4. Stevens-Johnson syndrome

Explanation

Acral, symmetric three-zone target lesions following herpes simplex infection are typical of erythema multiforme, which is an immune reaction to infection rather than to drugs. Mucosal involvement, when present, defines erythema multiforme major.

Question 34General dermatology: inflammatory, papulosquamous and eczematous disorders

Which histologic pattern is most characteristic of lichen planus?

  1. Neutrophilic spongiform pustules
  2. Nodular dermal infiltrate with plasma cells
  3. Band-like lymphocytic interface Correct answer.
  4. Subcorneal acantholysis with dyskeratosis

Explanation

Lichen planus shows a dense band-like lymphocytic infiltrate obscuring the dermoepidermal junction, with basal cell damage, saw-tooth rete ridges and hypergranulosis. Apoptotic keratinocytes (Civatte bodies) are also seen.

Question 35General dermatology: inflammatory, papulosquamous and eczematous disorders

A woman has a single thickened, lichenified, intensely itchy plaque on the nape of the neck that she scratches repeatedly. What is the most likely diagnosis?

  1. Lichen planus
  2. Lichen simplex chronicus Correct answer.
  3. Tinea corporis infection
  4. Psoriasis vulgaris of the nape

Explanation

Lichen simplex chronicus is a self-perpetuating itch-scratch cycle producing a well-demarcated lichenified plaque in an accessible site such as the nape. Breaking the cycle with a potent topical corticosteroid and advice on habit reversal is the mainstay of treatment.

Question 36General dermatology: inflammatory, papulosquamous and eczematous disorders

Which feature most favours scalp psoriasis over seborrheic dermatitis?

  1. Greasy yellow scale with ill-defined borders
  2. Lesions confined to hair-bearing areas
  3. Sharp margination extending past the hairline Correct answer.
  4. Prompt response to ketoconazole shampoo

Explanation

Psoriasis produces well-demarcated plaques with silvery scale that often extend beyond the hairline onto the forehead and nape. Seborrheic dermatitis tends to be ill-defined, greasy and confined to hair-bearing or sebaceous-rich areas.

Question 37General dermatology: inflammatory, papulosquamous and eczematous disorders

Which topical agent is preferred for atopic dermatitis on the eyelids and face when steroid-induced atrophy is a concern?

  1. Calcipotriol ointment
  2. Tacrolimus 0.1% ointment Correct answer.
  3. Clobetasol propionate 0.05% ointment
  4. Betamethasone dipropionate cream

Explanation

Topical calcineurin inhibitors such as tacrolimus and pimecrolimus do not cause skin atrophy and are therefore useful on the thin skin of the face and eyelids. They may transiently sting on application.

Question 38General dermatology: inflammatory, papulosquamous and eczematous disorders

New linear psoriatic plaques arising along a healed surgical scar illustrate which phenomenon?

  1. Wolf isotopic response
  2. Renbok phenomenon
  3. Koebner phenomenon Correct answer.
  4. Sporotrichoid spread

Explanation

The Koebner phenomenon is the appearance of lesions of an existing skin disease at sites of cutaneous trauma such as scratches, scars or burns. It is well described in psoriasis, lichen planus and vitiligo.

Question 39General dermatology: inflammatory, papulosquamous and eczematous disorders

Which finding on examination is recognised as a minor feature supporting a diagnosis of atopic dermatitis?

  1. Auspitz sign
  2. Wickham striae
  3. Dennie-Morgan fold Correct answer.
  4. Koebner phenomenon

Explanation

Dennie-Morgan folds are infraorbital creases included among the minor features of atopic dermatitis, together with keratosis pilaris, palmar hyperlinearity and anterior neck folds. Diagnosis remains clinical and does not depend on any single minor criterion.

Question 40General dermatology: inflammatory, papulosquamous and eczematous disorders

Which feature separates erythema multiforme major from erythema multiforme minor?

  1. Acral distribution of the lesions
  2. History of preceding herpes simplex
  3. Two or more mucosal sites involved Correct answer.
  4. Presence of typical target lesions

Explanation

Erythema multiforme is classified as major when mucosal surfaces, such as oral, ocular and genital, are involved, often with systemic symptoms. Both forms share acral target lesions and a frequent herpes simplex trigger.

Question 41Infectious dermatology and sexually transmitted infections / venereology

What is the first-line topical treatment for classical scabies in an immunocompetent adult?

  1. Acyclovir 5% cream
  2. Mupirocin 2% ointment
  3. Permethrin 5% cream Correct answer.
  4. Clotrimazole 1% cream

Explanation

Permethrin 5% is a topical scabicide applied from the neck down and left on for 8 to 14 hours, then repeated after one week. Close contacts should be treated at the same time to prevent reinfestation.

Question 42Infectious dermatology and sexually transmitted infections / venereology

Which organism most commonly causes tinea corporis?

  1. Candida albicans
  2. Trichophyton rubrum Correct answer.
  3. Staphylococcus aureus
  4. Malassezia furfur

Explanation

Tinea corporis is a dermatophyte infection, and Trichophyton rubrum is the most frequent causative species worldwide. Potassium hydroxide microscopy shows septate branching hyphae.

Question 43Infectious dermatology and sexually transmitted infections / venereology

Which bacterium is the most frequent cause of non-bullous impetigo?

  1. Streptococcus pyogenes
  2. Staphylococcus aureus Correct answer.
  3. Pseudomonas aeruginosa
  4. Corynebacterium minutissimum

Explanation

Non-bullous impetigo is most often caused by Staphylococcus aureus, alone or together with group A streptococci. It presents with honey-colored crusted lesions around the nose and mouth.

Question 44Infectious dermatology and sexually transmitted infections / venereology

Molluscum contagiosum is caused by a virus from which family?

  1. Herpesviridae
  2. Picornaviridae
  3. Poxviridae Correct answer.
  4. Papillomaviridae

Explanation

Molluscum contagiosum is caused by a poxvirus and produces umbilicated, pearly papules. The diagnosis is usually clinical, and lesions resolve spontaneously in immunocompetent hosts.

Question 45Infectious dermatology and sexually transmitted infections / venereology

Which finding is characteristic of primary syphilis?

  1. A painful vesicle on an erythematous base
  2. A tender suppurative inguinal bubo
  3. A pruritic annular plaque with scale
  4. A painless ulcer with a clean base and indurated edges Correct answer.

Explanation

The primary syphilis chancre is a painless, indurated ulcer that appears at the inoculation site about three weeks after exposure. It heals spontaneously, and dark-field microscopy or NAAT can confirm Treponema pallidum.

Question 46Infectious dermatology and sexually transmitted infections / venereology

What is the recommended first-line treatment for uncomplicated urogenital gonorrhea in adults?

  1. Intramuscular ceftriaxone 500 mg as a single dose Correct answer.
  2. Oral penicillin V 500 mg four times daily for 7 days
  3. Oral azithromycin 1 g as monotherapy
  4. Oral doxycycline 100 mg twice daily for 14 days

Explanation

A single intramuscular dose of ceftriaxone 500 mg is first-line therapy for uncomplicated gonorrhea. If chlamydia has not been excluded, doxycycline is added for seven days.

Question 47Infectious dermatology and sexually transmitted infections / venereology

Which feature favors candidal intertrigo over dermatophyte infection?

  1. Black dots on the scalp
  2. A dry scaly advancing edge with central clearing
  3. Fluorescence under a Wood's lamp
  4. Satellite pustules outside the main patch Correct answer.

Explanation

Candidal intertrigo occurs in moist skin folds and typically shows satellite pustules or papules beyond the main erythematous area. Potassium hydroxide microscopy shows budding yeasts and pseudohyphae.

Question 48Infectious dermatology and sexually transmitted infections / venereology

Herpes labialis is most commonly caused by which virus?

  1. Varicella-zoster virus
  2. Human herpesvirus 8
  3. Epstein-Barr virus
  4. Herpes simplex virus type 1 Correct answer.

Explanation

Herpes labialis is usually caused by herpes simplex virus type 1. Recurrences are triggered by ultraviolet light, stress, fever, or local trauma and begin with tingling before vesicles appear.

Question 49Infectious dermatology and sexually transmitted infections / venereology

Which organism causes pityriasis versicolor?

  1. Propionibacterium acnes
  2. Candida glabrata
  3. Trichophyton mentagrophytes
  4. Malassezia species Correct answer.

Explanation

Pityriasis versicolor is caused by Malassezia yeasts and presents with hypopigmented or hyperpigmented macules on the trunk. Potassium hydroxide microscopy shows short hyphae and spores.

Question 50Infectious dermatology and sexually transmitted infections / venereology

What is the appropriate treatment for tinea capitis in a child?

  1. Oral griseofulvin or terbinafine Correct answer.
  2. Topical terbinafine cream alone
  3. Oral fluconazole for 3 days
  4. Topical ketoconazole shampoo alone

Explanation

Tinea capitis requires systemic antifungal therapy because topical agents do not penetrate the hair follicle adequately. Oral griseofulvin or terbinafine is used, with antifungal shampoo as an adjunct to reduce spread.