Terminology

Term	Definition
Abscess	local accumulation of pus
Bulla	raised circumscribed lesion >5mm containing serous fluid (blister) above the dermis
Comedone	plug of dead epithelial material blocking pore: open (blackhead) or closed (whitehead)
Erythema	blanchable redness of the skin that can be localised or generalised (dilation of BVs and capillaries)
Excoriation	scratch which has broken the surface of skin
Lichenification	skin thickening with exaggerated skin markings as a result of repeated rubbing
Macule	flat well-defined area of altered skin pigmentation. Areas >10mm are described as patches
Nodule	solid, palpable usually subcutaneous lesion >5mm
Papule	raised well defined lesion <5mm
Plaque	raised flat-topped lesion >20mm
Purpura	non blanching violaceous (purplish) discolouration of the skin due to blood that has extravasated from BVs
Pustule	raised well defined lesion containing pus
PUVA	psoralen plus Ultraviolet A
Vesicle	blister <5mm
Weal	transient lraised lesion with a pale centre and pink margin

History & Exam

How long has it been there?
Does it hurt?
Any other symptoms, eg itch?
Any other lumps
Is it getting bigger
Otherwise well?

6S’s of skin lesions

Site
Size
Shape
Smoothness
Surface
Surroundings

Does it tranilluminate?
Fixed/tethered?
Fluctuant/compressible?
Temperature
Tender?
Pulsatile

Intradermal	Subcutaneous
Sebaceous cyst	Lipoma
Abscess	Ganglion
Dermoid cyst	Neuroma
Granuloma	Lymph node
If a lump is intradermal you cannot draw the skin over it, while if the lump is subcutaneous, you should be able to manipulate it independently from the skin

Lipomas

Benign fatty lumps that occur wherever fat can expand (not scalp or palms)
Smooth imprecise margins
Slightly fluctuant
Not fixed
Symptoms usually due to pressure
Very rarely malignant change
Dercum’s disease - multiple scattered lipomas which may be painful - typically in post-menopausal women

Sebaceous cysts

Either epidermal or pilar cysts (not of sebaceous origin and contain keratin not sebum)
Firm, round, mobile subcutaneous nodules of varying size
Characteristic central punctum
Infection common - pus exits through centre
Treatment of bad ones is excision of cyst and contents

Epidermal

Keratosis

Solar (actinic) keratosis

Sun-exposed skin sites
Crumbly, yellow-white crusts
Malignant change to Squamous cell carcinoma may occur after several years
Cryotherapy, fluorouracil, imiquimod

Seborrheic keratosis

Looks scary but benign skin growth
Look waxy or scaly and slightly raised. They appear gradually, usually on the face, neck, chest or back.
Usually appear in numbers rather than a single lesion like in Melanoma

Keratosis pilaris

Cutaneous abscesses

Staphylococci most common organism.
Below the waist faecal organisms are common
Treatment incise and drain
Think Hidradenitis suppurativa if recurrent inguinal or axillary abscesses

Boils (furuncles)

Abscesses involving hair follicle and associated glands

Carbuncle

An area of subcutaneous necrosis which discharges itself on to the surface through multiple sinuses

Rheumatoid nodules

Collagenous granulomas which appear in established RA
On the extensor aspects on the joints - esp elbows

Ganglia

Degenerative cysts from an adjacent joint or synovial sheath
Commonly seeon on the dorsum of the wrist, hand or foot.
May transilluminate
50% disappear spontaneously
Bible smacker

Dermatofibromas

Can occur anywhere in body
Most commonly under skin
Whitish, benign tumour containing collagen, fibroblasts and fibrocytes

Dermoid cyst

Contain dermal structures
Found at junction of embryonic cutaneous boundaries eg midline or lateral to eye

Malignant tumours of connective tissues

Fibrosarcoma, liposarcomas, leiomyosarcomas, rhabdomyosarcomas
TNM grading
Needle-core biopsies
Refer to specialist

Neurofibromas

Caused by Neurofibromatosis
Autosomal dominant inheritance - expression of NF1 is variable even within a family

Keloids

Irregular hypertrophy of vascularised collagen forming rainsed edges at sites of previous scars that extend outside the scar
Common in dark skin
Treatment can be difficult - intralesional steroid Injections

Keratoacanthomas

Fast-growing benign, self-limitting papule plugged with keratin
May be confused with Squamous cell carcinoma