Basal cell carcinoma
- most common skin cancer
- typically on sun-exposed area (face, scalp, ears)
Malignant melanoma
- acts like other solid organ tumor
- life threatening if not caught eatly
SCC
- from keratinocytes
- can metastasize on lip, ear, or in immunosuppression
- prescurosr from actinic keratosis or bowen’s disease
Keratoacanthoma
- difficult to distinguish from SCC often excised for histology
- rapidly growing, crateiform nodule with central plug
Actinic keratoses
- pre-malignant due to UV exposure
- can progress to SCC
Condrodermatitis helicis
- caused from chronic pressure or trauma (eg. sleeping on one side)
- not malignant, but mimics SCC
-
Erythema Multiforme (EM)
Cause: Usually infection-related, especially Herpes simplex virus (HSV) or Mycoplasma pneumoniae.
Typical lesions:
Target (iris) lesions — concentric rings (dark center, pale halo, erythematous rim).
Mainly on palms, soles, extensor surfaces, face.
Mucosal involvement: Mild or absent.
Course: Self-limiting (1–2 weeks).
Management: Treat underlying infection; supportive care; acyclovir if HSV-related.
Stevens–Johnson Syndrome (SJS)
Cause: Severe drug reaction, most often to:
Sulfonamides, antiepileptics (phenytoin, carbamazepine, lamotrigine), allopurinol, NSAIDs.
Lesions:
Widespread erythematous or purpuric macules → blisters → epidermal detachment.
<10% body surface area (BSA) detachment.
Mucosal involvement: Prominent (oral, ocular, genital).
Systemic symptoms: Fever, malaise, pain.
Management:
Stop offending drug immediately!
Hospital admission (often burns unit), fluid + electrolyte balance, infection prevention, supportive care.
Toxic Epidermal Necrolysis (TEN)
Pathophysiology: Same disease spectrum as SJS — only more extensive.
BSA detachment: >30%.
Skin signs:
Sheets of epidermal loss, positive Nikolsky sign (skin shears off with gentle pressure).
Resembles severe burns.
Mucosal involvement: Severe, multi-site.
Mortality: 30–40% (due to sepsis, dehydration, organ failure).
Management:
Immediate cessation of culprit drug.
ICU/burns unit care (fluids, temperature control, infection prevention).
Consider IVIG or ciclosporin in severe cases.
Atopic eczema
Seborrhoeic dermatitis
Photodermatosis
Contact dermatitis
Contact irritant dermatitis
Vasculitis
Impetigo
