Dermatology Flashcards
Define androgenic alopecia
Progressive baldness
Symptoms of androgenic alopecia
- Usual pattern: bi-temporal recession; front and side thinning; hair often spared at occiput and thin band at sides (horse-shoe shape)
- Normal hair loss: 50-100/day
Cause of androgenic alopecia
In females, a loss of oestrogen increases the testosterone levels, leading to thinning
Treatment for androgenic alopecia
Private only:
- Minoxidil
- Finasteride (male only)
What is onychomycosis?
Fungal infection of the nail plate
Types of nail infection and symptoms
- Distal & lateral subungual
- Yellow/white, nail separates from bed - Superficial white
- Nail soft, dry, powdery; adherent to bed; not thick - Proximal subungual
- Nail surface intact; debris causes nail separation - Candida
- Thick nail plate, yellow/brown colour
Diagnostic test for onychomycosis
Nail Clippings : microscopy & culture
Diagnosis cannot be made clinically alone!
what is paronychia?
acute infection usually caused by s.aureus
Symptoms of paronychia
Erythematous, painful, throbbing, swollen lateral or proximal nail fold;
+/- purulence/abscess
What is atopic eczema?
Atopic eczema is a chronic, itchy, inflammatory skin condition.
- Affects all ages - most common in childhood
Symptoms of atopic eczema
Dry skin on:
• Neck
• Flexor surfaces of limbs
• Hands
Itchy, erythematous rash
Examples of steroids
Mild: hydrocortisone
Moderate: betamethasone
Strong: hydrocortisone 0.1 %, fluticasone
Very strong: Clobetasol
What is contact dermatitis?
any inflammatory reaction of the skin that results from direct contact with an offending agent
Types of contact dermatitis
- Irritant contact dermatitis (ICD) = caused by chemical irritant
- Allergic contact dermatitis (ACD) = caused by an antigen (allergen) that elicits a type IV (cell-mediated or delayed) hypersensitivity reaction
Difference in symptoms between ICD & ACD
ICD:
- Lesions erythematous,
- vesicles & crusting (rare)
- Sharp margins strictly confined to site of exposure
- Rapid onset (few hrs after exposure)
ACD:
- Lesions may be erythematous, papules, vesicles, erosions, crusts, scaling
- Initial sharp margins confined to site of exposure then spreading to periphery
- Onset 12-72hrs after exposure
- ITCHING!
define nappy rash
Nappy rash is an acute inflammatory reaction of the skin in the nappy area, which is most commonly caused by an irritant contact dermatitis.
Symptoms of nappy rash
Rash: well-defined areas of confluent erythema and scattered papules over convex surfaces
What is perioral dermatitis?
Associated w/ topical steroid use – direct or indirect (inadvertent transfer)
Features of perioral dermatitis
- clustered erythematous papules, papulovesicles and papulopustules
- most commonly in the perioral region but also the perinasal and periocular region
Define seborrhoeic dermatitis
chronic dermatitis thought to be caused by an inflammatory reaction related to a proliferation of a normal skin inhabitant, a fungus called Malassezia furfur
Features of seborrhoeic dermatitis
- eczematous lesions on the sebum-rich areas: scalp (may cause dandruff), periorbital, auricular and nasolabial folds
- otitis externa and blepharitis may develop
What conditions are associated with seborrhoeic dermatitis?
HIV
Parkinson’s disease
What areas do seborrhoeic dermatitis in children
It typically affects:
- scalp (‘Cradle cap’)
- nappy area
- face
- limb flexures
relatively common skin disorder seen in children.
Features of seborrhoeic dermatitis in children
Cradle cap -> early sign, 1st few weeks of life
Erythematous rash with coarse yellow scales
Define seborrhoeic keratoses
- Benign epidermal skin lesion in older people
- Most common benign cutaneous neoplasm
- Often called “Senile Keratosis”
- Inherited familial tendency
Features of seborrhoeic keratoses
- “Stuck to the skin” surface appearance
- flesh - light bown papule with a greasy, warty appearance
- Lesions are very common on the back (occur in sun-exposed areas)
- May be mistaken for malignant melanoma – so have a low threshold for biopsy!
Define nummular eczema/dermatitis
a long-term (chronic) skin condition that causes skin to become itchy, swollen and cracked in circular or oval patches.
AKA Discoid eczema
Features of nummular eczema/dermatitis
- Coin shaped lesions, 1-10cm, symmetric
- Vesicles and papules coalesce into plaques
- Pruritic
Define venous stasisi
Venous insufficiency with poor circulation
Predisposing factors:
- Varicose veins, cardiac failure, thrombophlebitis,
trauma/surgery to limb; age > 50
Features of venous stasis
- Hyperpigmented plaques on lower legs, usually anterior or medial
- Erythema
- Ulcers
+/- scale
+/- oedema
Define Actinic keratoses
common, sun induced premalignant skin lesions
- AKA ‘Solar keratosis’
Features of Actinic keratoses
- Small, crusty or scaly lesion
- Isolated red-brown macule/papule with a rough yellow-brown scale over it
- typically on sun-exposed areas e.g. temples of head
- multiple lesions
What is tinea versicolour?
- AKA Pityriasis versicolor
- superficial cutaneous fungal infection caused by Malassezia furfur
Features of tinea versicolour
- Multiple round or oval macules and confluent patches -most common
- Mild pruritus
- Found on trunk, neck +/- arms
- Colour:
- Patches may be copper/brown
- Pale patches on darker skin (versicolor albo) - May start as scaly and brown and then resolve through a non-scaly and white stage
Complication of Actinic keratoses
- After several years, a small percent of lesions may degenerate into squamous cell carcinomas (SSC)
- Examine patient carefully for Basal Cell Carcinoma as well.
What does tinea mean?
dermatophyte fungal infections
Types of tinea
tinea capitis - scalp
tinea corporis - trunk, legs or arms
tinea pedis - feet
Tinea corpis is also ….
AKA “ringworm”
Features of Tinea corpis
- Annular rash with a pale centrum. May have multiple rings
- erythematous lesions with pustules and papules
- Acute can be itchy at times, often asymptomatic
Tinea pedis is also …
AKA athlete’s foot
Features of tinea pedis
itchy, peeling skin between the toes
Define Pityriasis Rosea
self-limiting skin rash that mainly affects young adults
What is Pityriasis Rosea associated with?
herpes hominis virus 7 (HHV-7)
Features of Pityriasis Rosea
- Rash:
- Herald patch (usually trunk)
- Multiple, discrete, pink-red (‘salmon coloured’) or fawn coloured.
- Oval
- scaly — the centre tends to clear leaving the classical appearance of peripheral ‘collarette’ scaling around the edge of the lesion. - Distribution:
- symmetrical.
- a ‘Christmas tree’ pattern on the upper back and V-shaped pattern on the upper chest
and are distributed
Define psoriasis
- Chronic skin disorder.
- It generally presents with red, scaly patches on the skin
Features of psoriasis
- Sharply marginated erythematous papule with a silvery-white scale.
- Scales are loose and easily removed by scratching.
- Papules grow to sharply marginated plaques that coalesce with one another.
4. Distribution: o Scalp o Palms / soles / nails o Extensor surfaces of elbows / knees o Lower back / perineum o Anterior tibial surface
What is Dermatophyte Infections ?
- Group of fungi that infect non-viable keratinised skin structures
- Epidermal dermatophytosis – invades stratus corneum
- Trichomycosis – affects hair and hair follicles
- Onychomycosis – affects nail - Found in soil; transmission: humans or animals
- Worse in humid climates or warm moist body areas
Diagnosis of Dermatophyte Infections
KOH microscopy
Treatment of Dermatophyte Infections
clotrimazole, miconazole, terbinafine
Define lichen planus
Skin disorder of unknown aetiology
-> most probably being immune-mediated.
Features of lichen planus
- Four Ps:
- -> Pruritic, Purple, Polygonal, Papules
- -> rash with ‘white lines’ - Coalesce into plaques
- Wrists, ankles, shins, penis, mucous membranes
- oral involvement : a white-lace pattern on the buccal mucosa
What is acne vulgaris?
More common among teenagers due to ↑ sebum production secondary to ↑ androgen production.
Males > Females
Features of acne vulgaris
- Comedones are due to a dilated sebaceous follicle
- if the top is closed a whitehead is seen
- if the top opens a blackhead forms - Inflammatory lesions form when the follicle bursts releasing irritants
- papules
- pustules - This sequence of events can ultimately cause scarrin
What is rosacea?
Chronic skin disease of unknown aetiology
Features of rosacea
- “Flushing” or “heat on the face”
- -> typically affects nose, cheeks and forehead - telangiectasia are common
- later develops into persistent erythema with papules and pustules
- rhinophyma
- ocular involvement: blepharitis
- sunlight may exacerbate symptoms
Define folliculitis
- Pustular infection of hair follicles, usually caused by S. aureus
- —-> EXCEPT – hot tub folliculitis – pseudomonas
Features of folliculitis
Itchy, erythematous pustules – often clustered
What is exanthem?
common disease of infancy caused by the human herpes virus 6
- children aged 6 months to 2 years.
Exanthem also known as …
Roseola infantum
Features of exanthem
- high fever: lasting a few days, followed later by a rash
- maculopapular rash
- Nagayama spots: papular enanthem on the uvula and soft palate
- Other: diarrhoea and cough are also commonly seen
Types of herpes simplex
- Herpes Simplex 1 – Oral Herpes
- Herpes Simplex 2 – Genital Herpes
- HHV-3: Varicella
- HHV-4: Epstein-Barr (glandular fever)
- HHV-5:CMV
- HHV-6A, HHV-6B, HHV-7
- HHV-8: Kaposi’s sarcoma-associated herpesvirus
Features of herpes simplex
- primary infection: may present with a severe gingivostomatitis
- cold sores
- painful genital ulceration
- Vesicular lesions, erythematous, may be burning or tingling in nature
What is molluscum contagiosum?
Common skin infection caused by molluscum contagiosum virus
Transmission of molluscum contagiosum
Directly by close personal contact, or indirectly via fomites
Features of molluscum contagiosum
- pinkish or pearly white papules with a central umbilication.
- Lesions appear in clusters in areas anywhere on the body (except the palms of the hands and the soles of the feet).
- In children, lesions are commonly seen on the trunk and in flexures, but anogenital lesions may also occur.
- In adults, sexual contact may lead to lesions developing on the genitalia, pubis, thighs, and lower abdomen. Rarely, lesions can occur on the oral mucosa and on the eyelids.
What is a verruca?
A verruca (also known as a plantar wart) is a wart on the sole of the foot.
Features of verruca
- They often have central dark dots (thrombosed capillaries) and may be painful.
- Clinical diagnosis
What is condylomata also knwon as?
genital warts
- Not preventable with condom use!
- Highly contagious
Symptoms of genital warts
- Soft, skin coloured, fleshy warts on genitals or rectum
2. May bleed or itch
What is varicella-zoster infection?
Chickenpox
- shingles is reactivation of VZV (herpes zoster)
Symptoms of chickenpox
- fever initially
- itchy, rash starting on head/trunk before spreading. Initially macular then papular then vesicular
- systemic upset is usually mild
Symptoms of shingles
prodromal period
- burning pain over the affected dermatome for 2-3 days
- fever, headache, lethargy
rash
1. initially erythematous, macular rash over the affected dermatome
- quickly becomes vesicular
- does not cross the midline.
Defin cellulitis
Inflammation of the skin and subcutaneous tissues
- infection by Streptococcus pyogenes or Staphylcoccus aureus.
Features of cellulitis
- commonly occurs on the shins
- erythema, pain, swelling
- there may be some associated systemic upset such as fever
- Clinical diagnosis
Define vasculitis
Inflammation of small vessels
- May be drug reaction (eg NSAIDs, Abx)
Aetiology of vasculitis
Aetiology unknown, but associated with autoimmune disorders, IBD, hypersensitivity; GI, renal, joints may be affected
Features of vasculitis
- Itching, burning purpuritic rash
- 1-3mm lesions, may coalesce; often on legs
Define impetigo
Superficial bacterial skin infection caused by either Staph aureus or strep pyogenes
Symptoms of impetigo
- ‘Golden’, crusted skin lesions – around mouth
2. Lesions tend to occur on the face, flexure, & limbs not covered by clothing
How is impetigo transmitted?
Spread via direct contact with discharges from scabs
- Bacteria invade the skin through minor abrasions
VERY CONTAGIOUS
What is erysipelas?
Localised skin infection caused by group A strep pyogenes
–> Affects superficial skin layers and associated lymphatic system (superficial cellulitis)
Symptoms of erysipelas
- Bright red skin (fiery red rash)
2. Painful, raised, well demarcated plaques; malaise, ‘streaking’ redness; often on face, lower extremities
Types of skin cancer
Basal cell carcinoma (BCC)
Features of Basal cell carcinoma (BCC)
- Begins as a small, smooth surfaced, well defined nodule
- Color pink to red
- “Pearly” or rolled translucent (flesh-coloured) border
- Telangiectatic vessels - may later ulcerate leaving a central ‘crater
- Sun-exposed sites, especially the head and neck account for the majority of lesions
- Slow growth
Referal for BCC
Routine
Ix for BCC
Biopsy mandatory to confirm diagnosis
Features of SCC
- friable and bleed easily
- crusted
- sun-exposed skin.
- Ulcerated
- Grows quicker than BCC (3-6 months)
Ix of SCC
Biopsy
Tx of SCC
Surgical excision with 4mm margins if lesion <20mm in diameter.
If tumour >20mm then margins should be 6mm.
How does malignant melanoma present?
typically presents as a new or changing pigmented (brown or black) skin lesion
Features of melanoma
- altered pigmented lesion (ABCDE signs)
- melanocytic lesion that does not resemble surrounding melanocytic naevi (‘ugly duckling’)
- spontaneous bleeding or ulceration of a pigmented lesion
- constitutional symptoms
- Single nail striata
Ix of melanoma
Dermoscopy
Skin biopsy
Immunohistochemistry
Tx of melanoma
- surgical excision
2. Targeted therapies such as immune checkpoint inhibitors and BRAF inhibitors
What is Kaposi’s sarcoma?
neoplasm that is associated with human herpesvirus-8 (HHV-8)
Features of Kaposi’s sarcoma
- multifocal cutaneous lesions
- Vary in colour + size
- papular, nodular, plaque-like, bullous-like, or fungating with skin ulceration
2. mucosal lesions
3. Lymph node or visceral involvement
Ix of Kaposi’s sarcoma
Biopsy and histopathology
What is Cutaneous T-cell lymphoma?
clonal accumulation of T lymphocytes primarily or exclusively in the skin.
Features of Cutaneous T-cell lymphoma
Diagnosis can be difficult as the condition can take many different forms in the skin:
- flat patches
- raised plaques
- large tumours
- and/or marked erythroderma (intense and widespread reddening of the skin).
- pruritic
Ix for Cutaneous T-cell lymphoma
- Biospy
- PCR for T-cell receptor
Mx of Cutaneous T-cell lymphoma
- Skin directed therapy
- Radiotherapy
- Chemo
