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