Common Rashes Flashcards
Clinical features of acute eczema
Papulovesicular erythematous lesions
Itch
Ill defined
Oedema
Ooze or scaling and crusting
Histology of acute eczema
Inflammatory infiltrate in the upper dermis
Fluid collections
Clinical presentation of chronic eczema
Lichenification
Elevated plaques
Increased scaling
Excoriation
Secondary infection
Clinical feature of adult eczema
Generalised dryness and itching, hand eczema may be the primary manifestation of
Clinical feature of childhood eczema
Predominantly flexural
Clinical features of infantile eczema
Primarily involves face, scalp, and extensor surfaces of the limbs
Nappy area usually spared
What kind of reaction is contact allergy dermatitis
Type 4 hypersensitivity reaction to an external antigen
Sensitisation stage of contact allergic dermatitis
Generation of memory T cells following exposure to antigen via langerhans cells in the epidermis and MHC-II
Allergic stage of contact allergic dermatitis
Activation of sensitised Th cells in response to antigen causing the release of inflammatory cytokines and cell mediated cytotoxicity
Investigations for contact allergy dermatitis
Patch testing
What happens in patch testing
Allergens prepared into Finn chambers which are applied on the back and removed at 48 hours
What is contact irritant dermatitis
Non-specific physical irritation
What can cause contact irritant dermatitis
Soap
Water
Cleaning products
Nappy rash
Where does contact irritant dermatitis usually present
On the hands
Genetic association with atopic eczema
Mutations in fillagrin gene
Clinical features of atopic eczema
Ill defined erythema and scaling
Itch-scratch cycle
Generalised dry skin
What distribution is seen in atopic eczema
Flexural
Complication of atopic eczema
nodular prurigo
What is nodular prurigo
Itchy nodules or papules on the skin
What is atopic eczema usually associated with
Asthma, allergic rhinitis, food allergy
Diagnostic criteria for atopic eczema
Itching + 3 or more of the following:
Visible flexural rash or history
History of atopy
Generally dry skin
Onset before age of 2
Management of atopic eczema
Targeted blocking of IL4 and IL14
Drug related eczema
Type 1 or 4 hypersensitivity, eosinophils will be present
Photo-induced or photosensitive eczema
Well defined
Patients are often atopic
Reaction to UV light OR secondary to photosensitising drugs
What causes lichen simplex
Physical trauma to skin
What causes stasis dermatitis
Physical trauma to skin caused by increased hydrostatic pressure of the blood (venous insufficiency)
Where is stasis dermatitis seen
Lower legs
What is discoid eczema
Eczema which occurs in well defined circular or oval patches
What is another name for seborrhoeic eczema
Cradle cap
Where does seborrhoeic eczema tend to affect
Nose, eyebrows, ears and scalp
When does dyshidrotic eczema occur
When there is a very sudden acute flare up of eczema and the spongiotic vesicles join together
Clinical presentation of dyshidrotic eczema
Tiny blisters develop in hands and feet
Classically on the sides of fingers
What is another name for dyshidrotic eczema
Pompholyx eczema
General measures for managing eczema
Avoid irritants
Loose cotton clothing
Emollients
Management of mild eczema
Topical steroid
Management of moderate eczema
Moderate topical steroid
Give an example of a moderate topical steroid
Betamethasone valerate 0.025%
Management of severe eczema
Potent topical steroid
Consider occlusive dressings
Treat infection if that’s a factor
Secondary care options for the management of eczema
Phototherapy
Immunosuppression
Biological agents
What is psoriasis
A common chronic inflammatory dermatosis
Genetic links in psoriasis
Associated with HLA genes and PSORS1 locus
When does psoriasis usually present
2 peaks in incidence
20s and 50s
Precipitating factors for psoriasis
Stress
Trauma
Alcohol and smoking
Infection
HIV/AIDS
Drugs
Name some drugs associated with psoriasis
B blockers
Lithium
Anti malarial drugs
What causes rebound psoriasis
Swift withdrawal of topical or systemic steroids
What is the Koebner phenomenon
The development of new skin lesions on previously unaffected skin following trauma, injury or irritation
Give an example of an infection which can precipitate psoriasis
Strep throat
Pathophysiology of psoriasis
Hyperproliferation of epidermal cells
Clinical presentation of psoriasis
Symmetrically distributed, red scaly plaques with well defined edges
Scale is silvery white
Itchy
Common sites for psoriasis
Scalp, elbows and knees
What is auspitz sign
When psioritic plaques are scraped or removed, pinpoint bleeding points are observed on the skin surface
Name 3 nail changes that can be seen in patients with psoriasis
Nail bed pitting
Onycholysis
Subungual hyperkeratosis
What is nail bed pitting
Superficial depressions in the nail bed
What is onycholysis
Separation of the nail plate from the nail bed
What is subungual hyperkeratosis
Thickening of the nail bed
What is the commonest type of psoriasis
Chronic plaque psoriasis
Presentation of chronic plaque psoriasis
Symmetrical plaques on the extensor surface of the limbs, scalp and lower back
Plaques are raised with silvery scale
How does flexural psoriasis present
Smooth, erythematous plaques without scale in flexures and skin folds colonised by candida yeasts
Where does flexural psoriasis present
Groin, axilla, inframammary areas
Management of flexural psoriasis
Mild topical steroid + antifungal preparations
When does guttate psoriasis occur
After a strep infection in young adults
What does guttate psoriasis present like
Multiple small, tear drop shaped erythematous plaques
Where does guttate psoriasis present
On the trunk
How does pustular psoriasis present
Multiple petechiae and pustules on the palms and soles
Causes of pustular psoriasis
Withdrawal of steroids, infection, pregnancy, hypocalcaemia
Causes of erythrodermic psoriasis
Withdrawal of potential topical or systemic steroids
Drug reactions
UV burns
Management of erythrodermic psoriasis
Fluid balance, bed rest, emollients, systemic immunosuppression
Unstable plaque psoriasis
The rapid extension of existing or new plaques
Histological features of psoriasis
Rete pegs
Munro micro-abscesses in stratum corneum
Expanded prickle cell layer
Management pathway for psoriasis
- Topical
- Phototherapy
- Oral treatments
- Biologic therapy
Topical treatments for psoriasis
Topical corticosteroids
Emollients
Tar preparations
Vitamin D analogues
Salicylic acid
What is acne
Inflammatory condition of the pilosebaceous unit
When does acne present
12-24
Diet associated with acne
High glycemic index and excess dairy consumption
Pathophysiology of acne
Increased androgens at puberty
Hypercornification causes keratin plugging of pilosebaceous unit
Infection with corynebacterium acnes within sebum in the hair follicles
Production of comedones due to the build up of keratin and sebum
Rupture causes acute inflammation
Closed comedones
whiteheads
Open comedones
Blackheads
Acne conglobata
Severe form of nodulocystic acne
Acne fulminans
Acute, painful, ulcerating and haemorrhagic clinical form of acne
Where does acne present
Reflects sebaceous gland sites
Face, upper back, anterior chest
Complications of chronic acne
Atrophic scars and hyperpigmentation
Mild acne
Comedones, papules and pustules
Moderate acne
Numerous papules, pustules and mild atrophic scarring
Severe acne
Numerous papules, pustules, severe atrophic scarring and cysts and nodules
Histology of acne vulgaris (3)
Dilated follicular opening with cellular debris and bacteria
Leukocytes and fragmented hair shaft
Marked perifollicular inflammation
Management of mild acne
Topical treatment
Management of moderate acne
Topical treatment and oral antibiotics
Management of severe acne
Isotretinoin
Topical treatments for acne
Benzoyl peroxide
Retinoids
Topical antibiotics
Caution of benzoyl peroxide
Bleaches clothes etc.
Systemic treatments of acne
Oral antibiotics
Contraceptives
Give some examples of oral antibiotics used in acne
Erythromycin, doxycycline, lymecycline
Who usually presents with rosacea
Women in 30-40s
Pathophysiology of rosacea
Involves chronic inflammation of the skin and is especially associated with triggers that increase body temp
Clinical presentation of rosacea
Recurrent facial blushing
Erythema with papules and pustules on the nose, chin cheeks and forehead - sparing of naso-labial folds
Thickening of the skin
Management pathway for rosacea
- Topical metronidazole
- Topical therapies + doxycycline
- Isotretinoin
Complications of rosacea
Rhinophyma
Telangiectasia
Ocular inflammation
What is rhinophyma
Thickening of skin on the nose resulting in a bulbous and enlarged appearance
What is the most common lichenoid disorder
Lichen planus
What characterises lichenoid disorders
Damage to the basal epidermis
What condition is associated with lichen planus
Hepatitis C
Clinical presentation of lichen planus
Itchy flat-topped violaceous papules
Oral lesions - lacy white on the inside of the cheek
Distribution seen in lichen planus
Flexor surfaces if the wrist/forearm, ankles and legs
Histology of lichen planus
Irregular sawtooth acanthosis
Hypergranulosis and orthohyperkeratosis
Upper-dermal infiltrate of lymphocytes
Basal damage with formation of cytoid bodies
Management of lichen planus
Topical steroid + antihistamine
