Dermatology Diseases Flashcards
What are the two types of eczema?
Atopic eczema and contact dermatitis
What is the clinical presentation of eczema?
- Itchy red rash
- Crusting, scaling and oozing
- Atopic eczema= Normally in skin folds such as elbow and knee
- Contact dermatitis= Sharply demarcated skin inflammation
What is the pathophysiology of atopic eczema?
A defect om the epithelial barrier (Thinning of stratum corneum due to damaged fillagrin) which allows irritants in to come into contact with T helper 2 cells (CD4) lymphocytes. This leads to inflammation.
What is the aetiology of atopic eczema?
Genetics and exacerbating elements
What is the epidemiology of atopic eczema?
Most common form
What is the pathophysiology of contact dermatitis?
Chemical irritants lead to a type IV hypersensitivity reaction
What is the aetiology of contact dermatitis?
Exposure to irritants
What is the epidemiology of contact dermatitis?
Women more than men
What is the treatment path of eczema?
- Avoid irritants
- Emollient therapy (E.G. E45)
- Topical corticosteroids
- Topical calcineurin inhibitor
How much emollient should be applied for eczema?
Apply 3-4 times a day
- 250-500g/week for child
- 500-750g/week for adult
What topical corticosteroids can be used in eczema?
Mild= Hydrocortisone
Moderate= Clobetasol butyrate
Potent= Flucinonide
Very potent= Clobetasol propinate
How is eczema diagnosed?
High serum IgE in 80%, and must have itchy skin condition in last 6 months. Plus 3 or more of-
- History of involvement of skin creases
- History of asthma/ Hay fever
- Generally dry skin
- Onset in childhood
What are possible complications of eczema?
Scratching will lead to broken skin, which then causes opportunistic infection.
What is the most common malignant skin cancer?
Basal cell carcinoma
Briefly describe the pathophysiology of basal cell carcinoma
Slow growing, locally malignant epidermal tumour. Thought to arise from hair follicles. Infiltrates local tissues through slow irregular growth of fingerlike outgrowths
What are the risk factors for basal cell carcinoma ?
UV exposure
Skin type 1: skin that burns and doesn’t tan
Aging
How is basal cell carcinoma diagnosed?
Biopsy
What is the clinical presentation of basal cell carcinoma ?
Non-pigmented in 95%
Border of ulcerated lesions is raised with peachy appearance
Majority occur in elderly on head and neck
Slowly enlarging, shiny nodule, which bleeds following minor trauma
Slowly causes local tissue destruction
Slowly invasive= Rarely metastasises
How is basal cell carcinoma treated?
Surgically excised with white borders and histology to ensure clear and adequate tumour margins
Superficial BCCs can be managed with non surgical treatment= Cryotherapy, photodynamic therapy
Radiotherapy in those unable to tolerate surgery
What are some complications of basal cell carcinoma ?
Maetastasis are rare (5%) but very hard to treat. Damage occurs if local spread reaches other structures
What is bowen’s disease?
In situ squamous cell carcinoma confined to the epidermis
What is the epidemiology of squamous cell carcinoma?
2nd most common skin cancer, just below basal cell carcinoma= 20% of non-melanoma skin cancer
What are the risk factors for squamous cell carcinoma?
Age
UV exposure
Chronic inflammation e.g. wound scars
What is the clinical presentation for squamous cell carcinoma?
Tends to present in later life
Most common on sun-exposed sites
Lesions are often keratoic, ill defined nodules that may ulcerate
They can grow rapidly
Ulcerations on lower lip or ear are more aggressive
Examinations of the regional lymph nodes is essential to look for metastasis
How is squamous cell carcinoma diagnosed?
Biopsy
Examine regional lymph nodes to look for metastasis
How is squamous cell carcinoma treated?
Surgical excision with minimal margin of 5mm
Radiotherapy is also used
What are some complications of squamous cell carcinoma?
Metastasis are rare (5%) but hard to treat
What is cellulitis?
A poorly demarcated bacterial infection of dermis and sub-cutaneous tissue
What is the epidemiology of cellulitis?
Preferentially involves lower extremities
What is the aetiology of cellulitis?
- Group A beta-haemolytic strep e.g. S. Pyogenes (Most common)
- Staph. Aureus
- MRSA