Dermatology Flashcards
What do anti-CCP abs present indicate?
Psoriatic Arthritis
What is Urticaria, how does it present, and how do we manage it?
Urticaria is swelling of the superficial dermis that raises the epidermis. It is caused by a local increase in permeability of capillaries and small venules largely mediated by histamine.
Px: itchy wheals
Rx: anti-histamines, or corticosteroids for severe acute urticaria
Angioedema: Presentation, management, and complications
Px: Swelling of the tongue and lips (due to deeper swelling involving the dermis and subcut tissue)
Rx: Corticosteroids
Complications: asphyxia, cardiac arrest and death
Anaphylaxis: Presentation, Management and Complications
Px: bronchospasm, facial and laryngeal oedema, hypotension; can present initially as urticaria or angioedema
Rx: Adrenaline, corticosteroids, and anti-histamines
Complications: Asphyxia, cardiac arrest and death
What are the causes of Erythema Nodosum?
Group A beta-haemolytic streptococcus Primary TB Pregnancy Malignancy Sarcoidosis Inflammatory Bowel Dx (IBD) Chlamydia Leprosy
Erythema Nodosum Px?
Located on shins
Discrete tender nodules that last 1-2 weeks before resolving and leaving discolouration but no scarring or atrophy.
Lesions do not ulcerate.
What is Stevens-Johnson Syndrome?
Mucocutaneous necrosis with at least 2 mucosal sites involved.
Drugs are most common association.
Epithelial necrosis with few inflammatory cells is seen on histology.
May have features overlapping with toxic epidermal necrolysis Eg prodromal illness
How do you distinguish between Stevens-Johnson syndrome and erythema multiforme?
The extensive necrosis in Stevens-Johnson
What is Toxic Epidermal Necrolysis?
An acute severe dx characterised by extensive skin and mucosal necrosis accompanied by systemic toxicity.
Usually drug-induced
Full thickness epidermal necrosis with subepidermal detachment on histology.
What is the cause of acute meningococcaemia?
Gram -ve diplococcus Neisseria meningitides
What is acute miningococcaemia?
Meningococcemia is a rare infectious disease characterized by upper respiratory tract infection, fever, skin rash and lesions, eye and ear problems, and possibly a sudden state of extreme physical depression (shock) which may be life-threatening without appropriate medical care.
Transmitted via resp secretions.
Px: Typical meningitis features (headache, fever, neck stiffness) + myalgia + septicaemia + rash.
Describe the rash present in acute meningococcaemia.
Non-blanching purpuric rash on the trunk and extremities.
May have had a blanching maculopapular rash 1st.
Can rapidly progress into ecchymoses, haemorragic bullae and tissue necrosis.
How do you manage acute meningococcaemia?
Abx (Eg benzylpenicillin)
Prophylactic Abx (Eg Rifampicin)for close contacts within 14 days
List the common complications of acute meningococcaemia.
Septicaemic shock
DIC (Disseminated intravascular coagulation)
Multi-organ failure
Death
Where are the extensor areas of the skin?
Knees, elbows, shins.
Where are the most common pressure areas of the skin?
Sacrum, buttocks, ankles, heels.
How does erythema multiforme present?
Target lesions!
No mucosal involvement.
Assoc. with HSV infection.
Self-limiting.
How does ringworm (Tinea corporis) present?
Annular lesions on buttocks, trunk, arms and legs.
May be itchy.
What is erythema?
Redness (due to inflammation and vasodilatation) which blanches on pressure
What is purpura?
Red or purple colour (due to bleeding into the skin or mucous membrane) which does not blanch on pressure – petechiae (small pinpoint macules) and ecchymoses (larger bruise-like patches)
Vesicle vs Bulla vs Pustule
Vesicle is a raised, clear fluid-filled lesion <0.5cm in diameter.
Bulla is the same but >0.5cm.
Pustule is vesicle containing pus.
Bulla is big blister, vesicle is small blister
Hirsutism vs Hypertrichosis
Hirsutism is androgen-dependent hair growth in females.
Hypertrichosis is non-androgen dependent excessive hair growth (Can be in males and females).
What are the conditions clubbing is associated with?
Suppurative lung disease, cyanotic heart disease, inflammatory bowel disease and idiopathic
What is koilonychia and what does it indicate may be present?
Iron-deficiency anaemia, congenital or idiopathic causes.
Onycholysis: definition and associations.
Onycholysis is separation of the distal end of the nail plate from the nail bed.
Assoc. with trauma, psoriasis, fungal nail infections and hyperthyroidism.
Nail pitting: definition and associations.
Pitting is punctuate depressions of the nail plate.
Associations: psoriasis, eczema, + alopecia areata.
What is Eczema Herpeticum (Kaposi’s varicelliform eruption)?
Widespread eruption - a serious complication of atopic eczema ( + other skin conditions)
Caused by Herpes Simplex Virus
Px of Eczema Herpeticum?
Extensive crusted papules, blisters and erosions.
Systemically unwell with fever and malaise.
Hutchinson’s sign: pustules on the end of the nose. Indicated trigeminal involvement - precedes opthalmic herpes zoster infection (VERY BAD!)
Rx of Eczema Herpeticum?
Antivirals (Eg Aciclovir)
Abx for secondary bacterial infection
Complications of Eczema Herpeticum
Herpes hepatitis
Encephalitis
DIC
What is Necrotising Fasciitis?
Necrotising Fasciitis is a rapidly spreading infection of the deep fascia with secondary tissue necosis.
Causes of necrotising Fasciitis?
Group A Haemolytic streptococcus.
Or a mixture of aerobic and anaerobic bacteria.
Risk factor = abdo surgery + co-morbidities
Necrotising Fasciitis Px
Severe pain
Erythematous, blistering + necrotic skin.
Systemically unwell with fever and tachycardia
Crepitus (subcutaneous emphysema)
X-ray may show soft tissue gas
Management of necrotising fasciitis?
Urgent extensive surgical debridement
IV abx
Mortality up to 76%
What is cellulitis?
Spreading bacterial infection of the skin involving the deep subcut tissue
What is erysipelas?
An acute superficial form of cellulitis that involves the dermis and upper subcut tissue.
Causes of cellulitis?
Streptococcus pyogenes + Staphylococcus Aureus
Px of cellulitis
- Most common in lower limbs
- Local inflammation - swelling, redness, warm, pain
- systemically unwell w/ fever, malaise or rigors
How do you distinguish erysipelas from cellulitis?
Erysipelas has a well-defined, red raised border.
Cellulitis management
Abx (Eg Flucloxacillin or benzylpenicillin).
Rest, leg elevation, sterile dressings and analgesia
Staphylococcal scalded skin syndrome Px
- Infant/ young child
- worse over face, neck, axillae or groin
- A scald-like appearance then large flaccid bulla
- Perioral crusting
- Intra-epidermal blistering
- Painful lesions
- Recovery within 5-7 days
Staphylococcal scalded skin syndrome management
Abx (Eg a systemic penicillinase-resistant penecillin, Fusidic acid, erythromycin, or a cephalosporin)
Analgesia
Tinea corporis (Tinea fungal infection of the trunk and limbs) Px?
Itchy, circular or annular lesions with a clearly defined, raised, + scaly edge
Tinea cruris (Tinea fungal infection of the groin and natal cleft) Px?
Very itchy, similar to tinea corporis (circular or annular lesions with well defined raised and scaly edge)
Tinea pedis (Athlete’s foot) Px?
Moist scaling and fissuring in toewebs, spreading to the sole and dorsal aspect of foot
Tinea manuum (Fungal hand infection) Px?
Scaling + dryness in palmar creases
Tinea capitis (Scalp ringworm) Px?
Patches of broken hair, scaling and inflammation
Tinea unguium (Fungal nail infection) Px?
Yellow discolouration, thickened and crumbly nail
Tinea incognito (inappropriate of tinea fungal infection with topical or systemic corticosteroids) Px?
Ill-defined + less scaly lesions
Candidiasis skin infection Px?
White plaques on mucosal areas, erythema with satellite lesions in flexures.
Pityriasis/Tinea versicolor (Malassezia furfur infection) Px?
Scaly, pale brown patches on upper trunk that fail to tan on sun exposure
Usually asymptomatic
How do you confirm a diagnosis of a fungal skin infection?
- Skin scrapings
- Hair or nail clippings (for dermatophytes/tinea)
- Skin swabs (for yeasts)
Fungal infection management?
- Topical antifungals (Eg terbinafine cream)
- Oral antifungals (Eg Itraconozole) for severe, widespread, or nail infections
- Avoid topical steroids - can lead to tinea incognito
What is Chronic Plaque Psoriasis?
Chronic, relapse-remitting autoimmune dermatosis causing abnormal proliferation of keratinocytes
What age does Chronic Plaque Psoriasis commonly develop?
Bimodal onset - 30s and 60s
+ve family history
Chronic plaque psoriasis Px?
Well-demarcated, erythematous plaques distributed symmetrically on extensor surfaces.
Can also occur at sites of recent skin trauma (Koebner’s phenomenon) + in scalp.
Silvery surface scaling which can give pinpoint bleeding when gently scratched (Auspitz sign).
What are the main precipitating factors for chronic plaque psoriasis?
Drugs (lithium,beta-blockers), alcohol, smoking, stress
What is the management for chronic plaque psoriasis?
Emollients for moisturising.
1st line -topicalcorticosteroid + vitamin D analogue once daily
2nd line - topicalitamin D analogue twice daily
3rd line - topical coal tar preparation once/twice daily
For extensive or refractory dx, consider phototherapy and oral immunosuppressants + biologics
What is Guttate psoriasis?
Guttate psoriasis is diffuse small scaly ‘tear drop’ plaques on trunk and proximal limbs.
Commonly follows URTI by Streptococcus and most cases resole in 2-3 months.
Treat same as chronic plaque psoriasis
What is Pityriasis Rosea?
Pityriasis rosea is an inflammatory disorder of unknown cause that affects teens and young adults.
Pityriasis Rosea Px?
Herald patch (single oval red plaque with scaling on inside edge) followed by diffuse small annular patches with dry scaly surface in “Christmas tree” distribution on chest and back.
Non-itchy
Self-limits in 6-12 weeks
What typeof hypersensitivity reaction is anaphylaxis?
Type 1
Atopic Dermatitis Px?
Poorly-defined, itchy and scaly erythematous patches on flexural surfaces, neck and face
Litchenification of persistent scratching
What type of dermatitis is IgE mediated?
Atopic dermatitis
Atopic dermatitis treatment?
Emollients, topical corticosteroids, oral anti-histamines
What is a common complication of atopic dermatits?
Eczema herpeticum (HSV)
What is discoid dermatitis?
Multiple well-defined annular erythematous plaques with normal skin in-between
Intensly itchy.
Can occur at any age.
What is seborrhoeic dermatits?
Dermatitis affecting sebaceous gland-rich areas (nasolabial folds, eyebrows, post-auricular) due to proliferation of commensal fungus
Seborrhoeic dermatitis Px?
Poorly-defined pink, scaly plaques or patches
Presents as a cradle cap in infants.
Non-itchy
Associated with Parkinsons
Seborrhoeic dermatitis Rx?
Topical anti-fungals and corticosteroid
What is Irritant Contact dermatitis?
Caused by occupational exposure
Lesions usually confined to site of contact (classically hands)
What is allergic contact dermatitis?
Type 4 (T cell) hypersensitivity reaction
Commonly nickel
Dx by skin patch test
Blistering and vesicles less common than irritant dermatitis
What is stasis dermatitis?
Venous insufficiency in lower limbs.
See inverted champagne bottle appearance and Lipodermatosclerosis
Also hemosiderin deposition and venous ulceration is seen
