Derm Flashcards
Atopic dermatitis and eczema - Definition & Presentation
Eczema is an inflammatory skin condition characterised by dry, itchy skin w/ a chronic recurrence.
Acute eczema is used to describe a flare-up of symptoms.
Chronic is used when patients show signs of chronic inflammation (i.e. Lichenification)
Presentation:
- Pruritus
- Xerosis (dry skin)
- Erythema
- Scaling
- Papules
- Vesicles (cyst, fluid filled sac..)
Atopic dermatitis and eczema - Aetiology & Risk Factors
Causes/Risk Factors:
- Combination of Genetic & Environmental factors
- Defects in skin barrier
- Immune dysregulation following allergen exposure
Environmental factors:
- Irritants like Soaps and Detergents
- Food/Contact/Inhalant allergens
- Skin infections
- Vitamin E deficiency
- Hard water
- Family Hx
Atopic dermatitis and eczema - Epidemiology
Can happen at any age, but most are diagnosed within 5 years of life
Affects Females more than Males in younger populations
Occurs more often in Urban areas and in smaller families (environment plays large role)
Those exposed to less hygienic environments are less likely to get Eczema
Atopic dermatitis and eczema - Differentials
1) Seborrheic Dermatitis –> Greasy scale, not pruritic. Often affects cheeks, scalp, extremities and trunk.
Unlike Eczema the nappy area is usually affected
2) Irritant Contact Dermatitis –> Common in Nappy area, face and extensor surfaces in children. Results from exposure to irritating substances.
Usually less pruritic than Eczema
3) Allergic Contact Dermatitis –> Well-circumscribed erythematous lesions, often with spongiotic (swollen) papules, vesicles and crusting. Usually pruritic and asymmetrical.
Symptoms due to contact with allergenic substance - removal of the allergenic substance resolves issues
4) Scabies –> Severe pruritus, particularly at night. Papules, vesicles and most notably burrows. Occurs on wrists ankles, palms, soles, waist and groin
5) Psoriasis –> Well-circumscribed, erythematous lesions w/ silver scales, usually on extensor surfaces, especially on elbows and knees
6) Mycosis Fungoides –> initial presentations look similar to Eczema: erythematous plaques in random distribution and scale
Tend to be older at time of diagnosis than those w/ Eczema (average >50)
Atopic dermatitis and eczema - Investigations
Usually no tests are necessary - clinical diagnosis
Consider:
- IgE levels (only for those with Hx of food allergy)
- skin-prick testing (only for those with Hx of food allergy)
- patch testing -> Contact dermatitis
-skin biopsy -> differentiate from contact dermatitis, psoriasis & mycosis fungoides
Atopic dermatitis and eczema - Management
1st line: Emollients –> improve skin barrier function and rehydrate skin
consider:
- Intermittent topical corticosteroids –> hydrocortisone topical: (0.2 to 2.5%) apply sparingly to the affected area(s) twice daily
- Topical or oral antibiotic therapy (if cutaneous infection is suspected)
2nd line: Systemic immunosuppressive agent
Atopic dermatitis and eczema - Prognosis & Complications
Chronic disease - around 70% will have symptom resolution by puberty, but 50% subsequently have relapses
Milder cases can be maintained on emollient treatment w/ intermittent topical agents during flare ups.
Severe cases require combination treatment including ultraviolet light therapy and systemic immunosuppressants
Complications:
- Psychological stress = high chance
- Bacterial cutaneous infection and colonisation = medium chance
- Systemic adverse affects to topical corticosteroids = low chance
- Eczema Herpeticum = low chance –> Severe skin infection caused by herpes simplex virus in someone w/ Eczema
Cellulitis - Definition & Presentation
Cellulitis is an acute spreading infection of the deep dermis and subcutaneous tissue with visually indistinct borders
The most common causative bacteria are Streptococcus pyogenes and Staphylococcus aureus
Presentations:
- Redness
- Swelling
- Heat
- Tenderness
- Occurring in an extremity, unilaterally
- Well-demarcated, bright-red raised skin (erysipelas)
- Orange-peel appearance (Caused by superficial oedema around hair follicles which remain connected to the dermis)
There are different Classes of Cellulitis:
Class I — there are no signs of systemic toxicity and the person has no uncontrolled comorbidities
Class II — the person is either systemically unwell or systemically well but with a comorbidity (for example peripheral arterial disease, chronic venous insufficiency, or morbid obesity) which may complicate or delay resolution of infection
Class III — the person has significant systemic upset, such as acute confusion, tachycardia, tachypnoea, hypotension, or unstable comorbidities that may interfere with a response to treatment, or a limb-threatening infection due to vascular compromise
Class IV — the person has sepsis or a severe life-threatening infection, such as necrotizing fasciitis
Cellulitis - Aetiology & Risk Factors
Cellulitis develops when micro-organisms gain entry to the dermal and subcutaneous tissues via disruptions in the cutaneous barrier
Beta-haemolytic streptococci and Staphylococcus aureus are most commonly implicated as the causative agents of cellulitis
Can occur in hosts w/ altered immunity
Risk Factors:
- Diabetes
- Venous insufficiency
- Eczema
- Oedema & Lymphoedema
- Obesity
- Previous episodes of cellulitis
Cellulitis - Differentials
1) Necrotising fasciitis
-> Marked pain, often out of proportion to the exam, and necrotic bullous change are clinical clues
2) Thrombophlebitis, superficial
-> Tender, palpable cord along affected vein often present
-> Presence or recent presence of intravenous catheter or needle also suggests this diagnosis
3) Deep vein thrombosis
-> Tenderness of involved vein, history of prior deep vein thrombosis, prolonged immobility, or hypercoagulable state
4) Gout
-> Hx of Gout
-> area of skin involvement is closely associated with a joint, particularly the first metatarsophalangeal or knee joint
-> Urate crystals in joint aspirate
5) Lyme disease
-> Hx of Tick exposure
-> Target-like rash
6) Contact Dermatitis
Cellulitis - Investigations
Usually make the diagnosis based on history and examination only
Take Hx:
- Acute onset of red, painful, hot, swollen, and tender skin, that spreads rapidly
- Underlying comorbidities (such as diabetes mellitus) that predispose to infection?
- Recent trauma to the skin, for example, a bite, burn, or laceration?
- Fever, malaise, nausea, shivering, and rigors?
Examine:
- There is usually an obvious skin break where the infecting organism may have entered
- Usually on lower extremities and unilateral (bilateral very rare)
- There may be diffuse redness or a well-demarcated edge that can be marked with a pen in order to monitor progress
If there are systemic signs of infection or comorbidities you may test for:
- FBC
- ESR
- CRP
- U&Es
- Blood culture and sensitivities
Cellulitis - Management
Primary Care:
For Class I:
- High-dose oral antibiotic
-> First line = Flucloxacillin 500–1000 mg four times daily for 5–7 days
- + analgesia (Paracetamol/Ibuprofen)
- Advise to drink fluids and elevate leg to relieve oedema if applicable
- Advise to avoid compression materials
- Manage breaks in skin
- Weight management if obese
- Manage comorbidities
Think Referral if:
- You suspect an abnormal pathogen as the cause
- If the Cellulitis is recurrent
Arrange urgent hospital admission if:
- Class IV cellulitis (Sepsis)
- Class III (Systemic signs)
- Is very young (<1 years old)
- Is immunocompromised
- Issues with eyes/around eyes
- Class II w/ comorbidity
Hospital:
- Follow Sepsis protocol (Sepsis 6)
- If Sepsis is treated, monitor and give Intravenous Flucloxacillin
Cellulitis - Prognosis & Complications
Most episodes of cellulitis resolve with treatment, and major complications are absent
recurrence is common, and each episode increases the likelihood of subsequent recurrence as well as the length of hospitalization
Complications:
- Sepsis
- Recurrent cellulitis
- Lymphoedema
