Dermatology
Common rashes, skin cancer and dermatological emergencies.
- Atopic Dermatitis and Eczema How skin barrier failure and a Th2 immune response drive the itch, the stepwise emollient and topical steroid ladder, and recognising eczema herpeticum.
- Contact Dermatitis Telling irritant from allergic contact dermatitis by mechanism and distribution, when patch testing earns its place, and why occupational cases need reporting.
- Psoriasis The IL-23/Th17 axis behind the plaques, telling the clinical subtypes apart, the topical-to-biologic treatment ladder, and screening for psoriatic arthritis.
- Acne Vulgaris The four drivers behind comedones and inflammatory lesions, grading severity, the combination-first treatment ladder, and the isotretinoin pregnancy prevention programme.
- Rosacea Telling papulopustular rosacea from acne by the absence of comedones, matching treatment to subtype, and why ocular involvement needs urgent ophthalmology input.
- Urticaria and Angioedema The antihistamine dose-escalation ladder for chronic urticaria, and why bradykinin-mediated angioedema needs C1 esterase inhibitor rather than adrenaline.
- Lichen Planus The 6 Ps and Wickham striae that define it, its variants by site, the hepatitis C and drug associations, and why oral disease needs ongoing surveillance.
- Erythema Nodosum Why bruise-like, non-ulcerating pretibial nodules are a sign rather than a diagnosis, the long list of triggers to screen for, and recognising Lofgren syndrome.
- Cutaneous Fungal Infection Naming tinea by body site, recognising the annular active-edge plaque, why scalp and nail disease need oral rather than topical treatment, and tinea incognito.
- Cutaneous Warts Telling a wart from a corn with the paring sign, why watchful waiting is often reasonable, the salicylic-acid-before-cryotherapy evidence, and when a 'wart' needs biopsy.
- Impetigo Non-bullous versus toxin-mediated bullous disease, the hydrogen-peroxide-first treatment ladder, and why scalded skin syndrome and glomerulonephritis are distinct from the crusted rash itself.
- Folliculitis and Hidradenitis Suppurativa Why HS is a follicular occlusion disease rather than a primary infection, Hurley staging, and the antibiotic-to-biologic-to-surgical treatment ladder.
- Scabies Why itch takes weeks to start after a first infestation, the whole-household same-day permethrin regimen, and recognising highly contagious crusted scabies.
- Benign Skin Lesions The dimple sign, the punctum, and the stuck-on surface that identify dermatofibroma, cysts and seborrhoeic keratosis, and the features that mean a lesion doesn't fit a benign pattern.
- Lipoma The soft, mobile, non-tender findings that confirm a lipoma clinically, its rarer variants, and the size, depth and growth features that instead suggest liposarcoma.
- Malignant Melanoma The ABCDE and 7-point checklists for spotting it early, why nodular melanoma breaks those rules, and how Breslow thickness drives excision margins and staging.
- Basal Cell Carcinoma The pearly rolled edge that identifies nodular BCC, why cumulative sun exposure (not sunburn) is the driver, and when Mohs surgery beats standard excision.
- Squamous Cell Carcinoma and Bowen Disease Why SCC carries real metastatic risk unlike BCC, the actinic-keratosis-to-Bowen's-to-invasive-SCC spectrum, risk-stratified excision margins, and recognising Marjolin ulcer.
- Actinic Keratosis The field cancerisation concept behind recurrence, Olsen grading, choosing lesion-directed versus field-directed treatment, and the features that mean biopsy rather than more cryotherapy.
- Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Classifying SJS versus TEN by body surface area detached, the culprit drugs and HLA associations, and calculating SCORTEN to guide burns-unit-level supportive care.
- Skin Manifestations of Systemic Disease Acanthosis nigricans, pyoderma gangrenosum, dermatomyositis and vasculitic purpura as diagnostic signposts, and the systemic work-up each one should trigger.
- Skin Ulcers Telling venous, arterial and neuropathic ulcers apart by site and pain, why ABPI determines whether compression is safe, and the features that mean biopsy rather than more dressings.
- Pressure Sores Staging from non-blanching erythema to exposed bone, the SSKIN prevention bundle, and why increasing pain or malodour should raise suspicion of osteomyelitis rather than routine dressing changes.
- Burns Grading depth by pain and blanching, estimating %TBSA, the Parkland formula timed from injury not arrival, and recognising inhalation injury and non-accidental patterns.
- Haemangioma and Vascular Birthmarks Telling a proliferating-then-involuting infantile haemangioma from a vascular malformation that grows with the child, screening for PHACE and Sturge-Weber syndromes, and why Kasabach-Merritt phenomenon means it isn't an ordinary haemangioma.
- Describing a Skin Lesion The systematic distribution-morphology-colour-configuration vocabulary for any rash, and the bedside tests - diascopy, Nikolsky, Auspitz, Koebner - that add diagnostic information before any biopsy.