Medicine Notes Dermatology Notes
Undergraduate Medicine Degree. Year 4 Dermatology module
Includes:
- Melanocytic and non-melanocytic lesions
- Leg ulceration
- Eczema
- Skin manifestations of systemic disease
- Bacterial + viral infections
- Psoriasis
- Acne
- Fungi and infestations...
The following is a more accessible plain text extract of the PDF sample above, taken from our Dermatology Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:
Non-melanoma Cancers and Benign Tumours 2
Benign Tumours of Epidermis + Appendages 2
Premalignant Tumours of Epidermis + Appendages 4
Contact Dermatitis – irritant 14
Contact Dermatitis – allergic 14
The Skin and Systemic Disease 14
Bacterial + Viral Infections 17
Commensal and Pathogenic Bacteria 18
Melanocytic Naevi:
Melanocytes which fail to mature or migrate in utero
Congenital: 1% of children have small naevi (rare giant ‘bathing trunk’ naevi – high risk of malignancy; Mongolian blue spot – due to melanocytes in dermis, benign)
Acquired: develops after birth (usually <25 years old)
Junctional – macular
Compound – ‘warty’
Intradermal – smooth + dome shaped
Halo naevus – undergoing regression, benign
Blue naevus – melanocytes in dermis, usually benign, often extremities
Sinister features:
50% of melanomas arise from naevi
Changes in size
Irregular shape
Irregular colour
>1cm diameter
Itch
Bleeding/ulceration
Types:
Superficial spreading (common, usually legs in women + trunk in men)
Nodular (poor prognosis, may be amelanotic)
Lentigo maligna melanoma (usually on face in elderly, arise within lentigo maligna)
Acral (palms or soles, can occur in Asian or Afro-Caribbean)
Treatment:
Excision: optimum excision margin unknown, generally 1cm for every 1mm depth invasion
Chemotherapy or immunotherapy of limited use
Prognosis:
Depends on depth of invasion, or Breslow thickness (depth in mm from granular cell layer)
5YSR: depth<1.5mm (90%), 1.5-3mm (60%), >3mm (40%)
Squamous cell papilloma
Common tumour, arises from keratinocytes
May resemble viral wart clinically
Excision, or curettage with cautery to base is treatment of choice + histology should be checked
Seborrhoeic keratosis (basal cell papilloma, seborrhoeic wart)
Common benign epidermal tumour, unrelated to sebaceous glands
Cause: usually unexplained. Multiple lesions may be inherited (autosomal dominant), occasionally follows inflammatory dermatosis
Presentation: usually arise after age 50 (but flat inconspicuous lesions often visible earlier). Often multiple but may be single. Lesions more common face + trunk. Distinctive ‘stuck-on’ appearance; may be flat, raised or pedunculated; colour varies from yellow to dark brown and surface may have greasy scaling + scattered keratin plugs (‘currant bun’ appearance). Lesions may multiply with age but remain benign
DD: pigmented naevus, malignant melanoma, basal cell carcinoma (BCC), Afro-Caribbeans may have dermatosis papulosa nigra
Ix: biopsy needed only in rare dubious cases. Histology is diagnostic – lesions lies above general level of surrounding epidermis + consists of proliferating basal cells + horn cysts
Treatment: can safely be left alone. Ugly/easily traumatised ones can be removed with curette under local (also provides histology), or by cryotherapy
Skin tags (acrochordon)
Common benign outgrowths of skin. Affect mainly middle-aged + elderly
Cause: unknown. Trait is sometimes familial. Most common in obese women. Rare associations = tuberous sclerosis, acanthosis nigricans, acromegaly, diabetes
Presentation: occur around neck + within flexures. Look unsightly + may catch on clothing/jewellery. Soft, skin-coloured or pigmented pedunculated papules
DD: rarely confused with small melanocytic naevi
Treatment: small lesions snipped off with fine scissors, frozen with liquid nitrogen or destroyed with hyfrecator without local anaesthetic. No way of preventing new ones.
Linear epidermal naevus
These lesions are an example of cutaneous mosaicism and so tend to follow Blashko’s lines
Epidermoid and Pilar cysts
Common. Occur on scalp, face, behind ears, trunk
Often have a central punctum which secretes foul-smelling material when ruptured
Histologically, the lining of the cyst resembles normal epidermis (epidermoid) or outer root sheath of the hair follicle (pilar)
Occasionally, an adjacent foreign body reaction is noted
Treatment: excision, or excision followed by expression of contents + removal of cyst wall
Milia
Small subepidermal keratin cysts
Common on the face in all age groups
Appear as white millet seed-like papules of 0.5-2mm diameter. Occasionally seen in sight of previous subepidermal blister (e.g. in epidermolysis bullosa or porphyria cutanea tarda)
Contents of milia can be picked out with sterile needle without local anaesthesia
Chondrodermatitis nodularis helicis (painful nodule of the ear, ear corn)
Strictly, not a neoplasm, but a chronic inflammation
Painful nodule develops on helix (or antehelix) of ear, most often in men
Looks like small corn, tender and prevents sleep
Histologically, thickened epidermis overlies inflamed cartilage
Treatment: wedge-resection under anaesthetic successful if cryotherapy or Intralesional triamcinolone (steroid) injection fails
Keratoacanthoma
Some argue that this rapidly growing tumour should be classified as benign, but some do transform into squamous cell carcinoma
Cause: photosensitising chemicals (e.g. tar, mineral oils) act as cocarcinogens with UVR. They may also follow therapeutic immunosuppression
Clinical features: mainly occur on exposed skin in fair individuals. 2/3 on face, most of the rest on the arms. Lesion starts as a pink papule that rapidly enlarges (may reach 1cm in 1-2months). After 5-6weeks, centre of the nodule forms either a keratinous plug or a crater. If left, lesion...
Buy the full version of these notes or essay plans and more in our Dermatology Notes.
Undergraduate Medicine Degree. Year 4 Dermatology module
Includes:
- Melanocytic and non-melanocytic lesions
- Leg ulceration
- Eczema
- Skin manifestations of systemic disease
- Bacterial + viral infections
- Psoriasis
- Acne
- Fungi and infestations...
Ask questions 🙋 Get answers 📔 It's simple 👁️👄👁️
Our AI is educated by the highest scoring students across all subjects and schools. Join hundreds of your peers today.
Get Started