The paired photographs show xanthelasma at the eyelids and tendon xanthomata over the hand extensor tendons. Together they are a visual cue to assess for inherited or severe dyslipidaemia and obtain a lipid profile (which need not routinely be fasting). ^[1]

Why it matters: Chalazion vs stye is a classic exam discriminator. A chalazion is a granulomatous reaction to trapped meibomian secretion (chronic, non-tender), while a stye is an acute bacterial infection (tender, red, warm). If a chalazion recurs in the same spot in an elderly patient, consider sebaceous gland carcinoma – a rare but important "can't-miss." ^[1][7]

Think about:

• Periorbital cellulitis (preseptal) – infection anterior to orbital septum; eyelid erythema, swelling, warmth, but no proptosis, no ophthalmoplegia, no vision change
• Orbital cellulitis – infection posterior to septum; proptosis, restricted eye movements, reduced vision, pain on eye movement → ophthalmic emergency, needs IV antibiotics + CT orbit
• Allergic oedema (angioedema) – bilateral, non-tender, associated with urticaria elsewhere
• Blepharitis – chronic lid margin inflammation, crusting at lash bases, bilateral

This is one of the highest-yield sections. The lecture distinguishes:

Bilateral red eye with discharge:

• Viral conjunctivitis – watery discharge, follicles on tarsal conjunctiva, preauricular lymphadenopathy, often post-URTI. Adenovirus most common. ^[7]
• Allergic conjunctivitis – itchy, watery, papillae on tarsal conjunctiva, bilateral, atopic history
• Bacterial conjunctivitis – mucopurulent discharge, morning crusting, one eye then the other

Unilateral red eye with minimal discharge, mild tearing:

Ask: Pain? Loss of vision? Photophobia? ^[1]

This trio of questions is critical because they separate benign from sight-threatening:

Unilateral red eye associated with: Loss of vision (acute), periorbital pain, headache, malaise, nausea/vomiting → Think acute angle-closure glaucoma (AACG). ^[1]

Read the photographs before naming the condition:

• A sharply demarcated pool of blood under clear conjunctiva, with the rest of the eye quiet, is a subconjunctival haemorrhage.
• Thick yellow discharge matting the lashes supports bacterial conjunctivitis; watery bilateral injection is more typical of viral or allergic conjunctivitis.
• A localised sector of superficial redness with preserved vision and little pain supports episcleritis.
• Diffuse/circumcorneal injection, corneal haze and a fixed mid-dilated pupil are the visual danger pattern of acute angle-closure glaucoma.

Why AACG presents this way: The peripheral iris bows forward and physically blocks the trabecular meshwork → aqueous humour cannot drain → IOP rises rapidly (often > 40 mmHg) → corneal oedema (hazy cornea) → pain, halos around lights, nausea/vomiting (vagal response to pain). The pupil is mid-dilated and fixed because the iris sphincter is ischaemic. ^[7][8]

Why herpes labialis recurs in the same spot: HSV-1 establishes latency in the trigeminal ganglion. Reactivation sends virus along the same nerve branch to the same dermatome area, producing vesicles at the same location. Triggers include UV light, stress, immunosuppression, fever. ^[1]

• Mucocele – painless, translucent, bluish, dome-shaped swelling on lower lip or floor of mouth; caused by rupture of minor salivary gland duct → mucin extravasation. Fluctuant.
• Ranula – a large mucocele specifically on the floor of the mouth (sublingual gland)
• Fibroma (irritation fibroma) – firm, smooth, sessile nodule on buccal mucosa along bite line; due to chronic trauma
• Oral leukoplakia – white patch that cannot be scraped off → premalignant; needs biopsy
• Oral candidiasis (thrush) – white patches that CAN be scraped off revealing red base; in immunocompromised, denture users, inhaled steroid users

The slide's important visual contrast: the smooth, translucent lower-lip dome is a mucocele, whereas the irregular exophytic/ulcerated lesion on the lateral tongue is suspicious for oral squamous cell carcinoma. A persistent indurated lump, unexplained ulcer, mixed red-white change, spontaneous bleeding or cervical node should not be labelled “aphthous” from appearance alone—arrange urgent dental/oral-maxillofacial assessment and tissue diagnosis. Current NICE guidance uses unexplained oral ulceration lasting more than 3 weeks as a suspected-cancer referral trigger; follow the local pathway. ^[17]

• Acute pharyngitis / tonsillitis – erythematous pharynx ± exudates; viral (most common) vs bacterial (GAS – Centor criteria)
• Peritonsillar abscess (quinsy) – unilateral tonsillar swelling with uvular deviation to contralateral side, trismus, "hot potato" voice, drooling → needs urgent drainage
• Hand-foot-mouth disease – vesicles/ulcers on soft palate + hands/feet; Coxsackievirus A16 or EV71; children
• Herpangina – vesicles/ulcers on posterior palate/tonsillar pillars only (no hand/foot involvement); Coxsackievirus

Two white-throat photographs on the slide are not the same lesion:

• Oral candidiasis produces multiple soft white plaques over an erythematous palate/uvula and can usually be wiped away, leaving an erythematous or bleeding surface.
• A tonsillolith is a discrete white-yellow concretion sitting in a tonsillar crypt, often associated with halitosis or foreign-body sensation rather than a diffuse removable coating.

• Dental abscess – localized swelling, tender, may have draining sinus; refer to dentist
• Gingivitis – swollen, erythematous, bleeding gums; associated with poor hygiene; reversible
• Periodontitis – advanced gingivitis with loss of attachment and bone; pockets > 3 mm
• Epulis – localized gingival overgrowth; differential includes pyogenic granuloma, fibrous epulis, peripheral giant cell granuloma
• Drug-induced gingival hyperplasia – phenytoin, ciclosporin, nifedipine

Visual discriminator: gingivitis follows the gingival margin diffusely—red, swollen, shiny tissue that bleeds easily—whereas a focal punched-out ulcer, draining point or local fluctuant swelling should prompt a different diagnosis (ulcerative/infective disease or dental abscess) and dental assessment.

Acne Vulgaris:

• Pathogenesis: ↑sebum production (androgens) → follicular hyperkeratinization → C. acnes colonization → inflammation
• Lesions: open comedones (blackheads), closed comedones (whiteheads), papules, pustules, nodules, cysts
• Distribution: face, chest, back (sebaceous gland-rich areas)
• Grading: mild (comedonal), moderate (papulopustular), severe (nodulocystic)

Differentiate acne from: ^[1]

This section covers seborrhoeic dermatitis vs psoriasis vs eczema vs tinea – a massively important differential.

Seborrhoeic Dermatitis:

• Greasy, yellowish scales on erythematous base
• Distribution: scalp, eyebrows, nasolabial folds, behind ears, central chest
• Caused by Malassezia yeast → inflammatory response
• In infants = "cradle cap"
• Treatment: antifungal shampoo (ketoconazole), mild topical steroid

The facial photograph shows this distribution particularly well: subtle greasy erythema and scale cluster around the nasolabial folds, alae and central face, rather than forming sharply bordered plaques.

Psoriasis (covered on body/scalp slides too ^[1]):

• Well-demarcated, raised, erythematous plaques with silvery-white scales
• Distribution: extensor surfaces (elbows, knees), scalp, sacrum, nails
• Pathognomonic: Auspitz sign (pinpoint bleeding on removal of scale – due to thin epidermis over dilated capillaries)
• Koebner phenomenon (lesions at sites of trauma)
• Nail changes: pitting, onycholysis, oil-drop sign, subungual hyperkeratosis

On the scalp, the pictured plaque is sharply demarcated with thick white scale and extends just beyond the hairline (corona psoriatica); on the elbow, the same morphology appears on an extensor surface. These two views link distribution to diagnosis.

Eczema (Atopic Dermatitis):

• Itchy, poorly-demarcated, erythematous patches with vesicles, weeping, crusting (acute) or lichenification (chronic)
• Distribution varies by age: infants (face, extensor), children/adults (flexural)
• Associated with atopic triad (eczema, asthma, allergic rhinitis)

Tinea (Dermatophyte Infection):

• Annular, scaly patch with active, raised border and central clearing ("ringworm")
• Can affect face (tinea faciei), scalp (tinea capitis), body (tinea corporis), groin (tinea cruris), feet (tinea pedis)
• KOH preparation shows hyphae → confirms fungal infection

The photographs show an eczematous reaction pattern and then direct the examiner to look for scabies at the fingers:

• Acute/subacute eczema: poorly demarcated erythema with fine scale, small vesicles, crusting and excoriations.
• Chronic eczema: rubbing produces lichenification—thickened skin with exaggerated skin markings.
• Discoid (nummular) eczema: multiple coin-shaped, uniformly scaly plaques. Unlike tinea, scale is distributed through the plaque rather than concentrated at a raised advancing edge with central clearing.
• Scabies: intensely pruritic papules and short, thin, serpiginous burrows, especially in finger webs and on the sides of fingers/wrists. Nocturnal itch and similarly itchy close contacts are powerful discriminators; examine the umbilicus, waist, buttocks and genital region as appropriate.

Pompholyx remains a finger differential: look for numerous deep, clear “tapioca” vesicles on the sides of fingers/palms, usually without a scabetic burrow. A unilateral scaly hand with bilateral tinea pedis (“two feet, one hand”) instead supports dermatophyte infection.

The single annular lesion on this slide is tinea corporis, not urticaria:

• Annular plaque with a raised, scaly advancing edge and relative central clearing
• Often asymmetric and slowly enlarging; itch is common
• Scrape scale from the active edge for microscopy/culture when the diagnosis is uncertain
• Discoid eczema scales across the whole plaque and is less likely to show central clearing; granuloma annulare has a smooth, non-scaly ring of papules; an urticarial wheal is smooth, migratory and each lesion usually fades within 24 hours

Pityriasis (tinea) versicolor (slide 25): numerous hypopigmented, hyperpigmented or pink finely scaling macules coalesce over the upper chest, shoulders and back. The subtle “branny” scale distinguishes it from vitiligo (chalk-white, no scale), while the lack of an active annular border distinguishes it from tinea corporis. It is caused by Malassezia rather than a dermatophyte.

Herpes Zoster (Shingles):

• Unilateral, dermatomal distribution of grouped vesicles on erythematous base
• Preceded by prodromal pain (burning, tingling) in the same dermatome
• Pathognomonic: does not cross the midline (stays in one dermatome)
• Caused by reactivation of VZV in dorsal root ganglion
• Complications: post-herpetic neuralgia (PHN), herpes zoster ophthalmicus (V1 → Hutchinson sign = vesicle on nose tip → corneal involvement likely), disseminated zoster in immunosuppressed
• Treatment: antivirals (aciclovir, valaciclovir) within 72 hours of rash onset; analgesics

The illustrated diagnosis is chickenpox (varicella), not pityriasis rosea:

• Scattered papules, vesicles, and crusted lesions in different stages ("crops") on trunk, face, and limbs
• A mild fever/malaise prodrome may occur; the generalised rash is pruritic
• High-yield discriminator: lesions in different stages of evolution simultaneously (macule → papule → superficial vesicle → crust), concentrated on the trunk
• Caused by primary VZV infection; highly contagious
• Complications include secondary bacterial skin infection in children and pneumonia in adults; severity is greater in pregnancy and immunocompromise. ^[1][18]

Molluscum Contagiosum:

• Multiple discrete, smooth, dome-shaped, pearly/flesh-coloured papules with central umbilication
• Caused by poxvirus; spread by direct contact or fomites
• Common in children and immunocompromised adults
• Self-limiting (months to years); treatment if desired: cryotherapy, curettage, topical agents ^[1]

Do not confuse the two umbilicated rashes: molluscum papules are firm, pearly and usually asymptomatic without a febrile crop; varicella vesicles are fragile, inflamed, pruritic and occur at multiple stages. Deep-seated painful umbilicated lesions with lymphadenopathy require a broader infectious differential.

This is the melanoma vs benign naevus discrimination section.

The photograph is deliberately difficult: a dark, raised, keratotic lesion can be a benign seborrhoeic keratosis, but irregular outline, asymmetry or evolution keeps melanoma in the differential. “Stuck-on” texture is reassuring only when the whole lesion is convincingly typical; dermoscopy and biopsy—not visual confidence alone—settle an equivocal changing lesion.

ABCDE criteria for melanoma:

• "Ugly duckling" sign: the mole that looks different from all the patient's other moles → suspicious ^[11]
• Subtypes (from supporting notes ^[11]): superficial spreading (most common in Caucasians), nodular (rapidly growing dome, may be amelanotic), lentigo maligna (elderly, sun-damaged), acral lentiginous (most common in HK/Asian populations) – palms, soles, subungual

In Hong Kong / Asian populations, acral lentiginous melanoma is the most common subtype. Look for irregular pigmentation on palms, soles, or under the nail. ^[1][11]

The pictured facial lesion has the classic nodular BCC pattern: a shiny translucent/pearly papule with surface telangiectasia and focal central crust or ulceration. Pigment may be present, especially in darker skin. DDx of a pigmented facial lesion:

• Seborrhoeic keratosis – "stuck on" appearance, waxy surface, horn cysts; benign; most common benign skin tumour in elderly
• Dermatosis papulosa nigra – variant of seborrhoeic keratosis; small, dark papules on face of darker-skinned individuals
• Pigmented BCC – pearly edge, telangiectasia, pigmentation common in Asians ^[11]
• Melanoma – ABCDE criteria apply

Bleeding/crusting is a warning sign, not a diagnosis. Describe whether the lesion is pearly and rolled (BCC), keratotic/indurated or everted (SCC/keratoacanthoma), or bright-red and friable (pyogenic granuloma), then arrange tissue diagnosis for a suspicious lesion. Think malignancy or vascular lesion:

• Squamous cell carcinoma (SCC) – indurated nodule/plaque with hyperkeratotic or ulcerated surface, everted edge, contact bleeding; sun-exposed areas; risk factors: UV, immunosuppression, chronic wounds (Marjolin ulcer) ^[11]
• Basal cell carcinoma (BCC) – rodent ulcer with rolled pearly edge, telangiectasia, central ulceration; most common skin cancer; locally invasive, rarely metastasises ^[11]
• Pyogenic granuloma – rapidly growing, friable, bright red nodule that bleeds easily; benign vascular proliferation; often at sites of trauma
• Keratoacanthoma – rapidly growing dome-shaped nodule with central keratin plug; may mimic SCC; some consider it a well-differentiated SCC variant

DDx of painful, swollen finger joints:

• Rheumatoid arthritis – symmetrical, MCP and PIP joints, morning stiffness > 30 min, swan-neck/boutonnière deformities in chronic disease
• Osteoarthritis – DIP (Heberden nodes) and PIP (Bouchard nodes), bony swelling, first CMC joint
• Gouty tophi – firm, white/yellow deposits near joints; associated with chronic gout
• Psoriatic arthritis – asymmetric, may involve DIP, dactylitis ("sausage digit"), nail pitting, associated skin psoriasis
• Trigger finger – painful clicking/locking of finger in flexion; thickened A1 pulley

Read the three hand photographs as patterns:

• Bilateral MCP/PIP synovitis with ulnar drift supports chronic rheumatoid arthritis; DIP disease is unusual.
• Hard bony enlargement at DIP/PIP joints supports osteoarthritis rather than soft, boggy synovitis.
• A whole swollen digit (dactylitis) together with a scaly plaque or nail pitting supports psoriatic arthritis.

• Mallet finger – drooping DIP; extensor tendon rupture at distal phalanx; cannot actively extend DIP; caused by forced flexion injury (e.g., ball striking fingertip)
• Ganglion cyst ("There's a lump over the back of my hand") – firm, non-tender, fluctuant, transilluminant swelling, most commonly dorsum of wrist; benign, from joint capsule or tendon sheath; treatment: reassurance, aspiration, or excision if symptomatic ^[1]

• Plantar fasciitis – heel pain worst with first steps in the morning; tenderness at medial calcaneal tubercle
• Hallux valgus (bunion) – lateral deviation of great toe with medial bony prominence at 1st MTP; may be painful with shoe wear
• Gout – acutely red, hot, swollen 1st MTP (podagra); exquisitely tender; monosodium urate crystals (negatively birefringent under polarised microscopy)
• Ingrown toenail (onychocryptosis) – nail edge grows into periungual skin; pain, erythema, granulation tissue; great toe
• Verruca plantaris (plantar wart) – HPV-induced; firm, hyperkeratotic, may have black dots (thrombosed capillaries); painful on lateral compression (vs callus which hurts on direct pressure)

The slide places callus, plantar wart and corn side by side:

Avoid paring a suspected wart/corn in patients with impaired sensation, peripheral arterial disease or high-risk diabetic feet; uncertainty or ulceration warrants podiatry/foot assessment.

• Tinea pedis (athlete's foot) – interdigital maceration, scaling, fissuring between toes (especially 4th-5th web space); may be vesicular or moccasin type
• Pitted keratolysis – multiple small pits on sole; bacterial (Corynebacterium, Kytococcus); associated with hyperhidrosis and occlusive footwear; classically malodorous
• Hyperhidrosis – excessive sweating → secondary bacterial overgrowth → odour

These photographs are not a syndromic-facies quiz. They reinforce that facial expression is part of the first-look assessment: does the patient appear in pain, frightened, guarded, breathless, confused, withdrawn or acutely unwell? Use that observation to open a respectful question and complete the clinical assessment. A single expression cannot diagnose depression, cognitive impairment, pain severity or capacity.

In an OSCE, verbalise the observation without judgement: “The patient appears distressed/guarded; I would assess pain, vital signs, mental state and immediate safety, then ask what is worrying them.”

The images show a wheelchair user and a child with Down syndrome. The clinical lesson is to identify and offer reasonable adjustments, not to infer diagnosis, cognition or decision-making capacity from appearance.

• Ask the patient how they prefer to communicate and what assistance they need; speak to the patient directly, even when a carer is present.
• Establish the carer's role and obtain consent before sharing information. Capacity is decision-specific and must be assessed, not assumed.
• Consider physical access, positioning, sensory needs, extra consultation time, easy-read material or an interpreter/communication aid.
• Recognising Down syndrome can prompt syndrome-related preventive care, but the immediate encounter still begins with the patient's presenting concern and priorities.