Dermatology Flashcards
What is the aetiology of eczema?
Eczema is a chronic, relapsing, inflammatory skin condition. Certain triggers can bring it on/exacerbate it
What are some triggers for eczema?
Irritants, skin infections, extremes of temperature, dietary factors, stress, hormonal factors
What is the pathophysiology involved in eczema?
Eczema can be dry, scaly and red. There is lichenification due to constant scratching and rubbing causing hyper-pigmentation, acanthosis and hyperkeratosis.
What are the symptoms of eczema?
An itchy red rash with an extensor or flexural pattern, affects the cheeks first in infants
What are the signs of eczema?
Itch erythematous scaly patches, especially in the flexures
What is the diagnostic criteria for eczema?
Must have had an itchy skin condition in the past 6 months and >/= 3 of:
History of involvement of the skin creases
Personal history of asthma or hayfever (or a 1st degree relative if <4)
History of generally dry skin
Visible flexural dermatitis
Onset before 2 years of age (N/A if child is <4)
What is the treatment for eczema?
Baseline: manage triggers and emollients
Mild: + garments, wet wraps, pastes, bandages, topical corticosteroids and topical calcineurin inhibitors
Moderate: + sedative antihistamines + UV treatment
Severe: + systemic treatments (e.g. azathioprine, cyclosporin)
All stages: antibiotics/antiseptics as needed
What is the aetiology of psoriasis?
Appears to be polygenic but is also dependent on certain environmental triggers e.g. infection, drugs, UV light, alcohol abuse and possibly stress
What is the pathophysiology involved in psoriasis?
It is a papulo-squamous disorder characterised by well demarcated, red scaly plaques. The skin becomes inflamed and hyperproliferates.
What are the two peaks of onset for psoriasis?
16-22
55-60
What are the symptoms of psoriasis?
Red scaly patches with a silver scale, can be on extensor surfaces or flexural surfaces
What are the signs of psoriasis?
Nail changes: pitting, onycholysis, yellow-brown discolouration, subungual hyperkeratosis, damaged nail matrix
What tests are used to diagnose psoriasis?
Diagnosis is clinical and a biopsy is not usually required. Dermoscopy may be useful in differentiating guttate psoriasis from chronic pityriasis lichenoides
What is the treatment for psoriasis?
Emollients, topical vitamin D analogues, topical corticosteroids, topical retinoids, UV B, coal tar preparations, dithranol, methotrexate, ciclosporin, anti-TNF biologics
What is the aetiology of acne?
Genetic factors play a part and positive family history is also a factor, may be associated with PCOS and abnormal production of androgens
What is the pathophysiology of acne?
Key factors: seborrhoea, comedo formation, colonisation of the pilo-sebaceous ducts with P. acnes and inflammation of the pilosebaceous unit
What are the symptoms of acne?
Greasy skin with a mixture of comedones, papules and pustules. Can also present with cysts - can be painful. Acne mostly occurs on the face, back and chest.
What are the signs of acne?
No obvious physical signs.
What tests are used to diagnose acne?
Usually no investigations are required, investigations are occasionally required to explore a possible underlying cause
What is the treatment for acne?
Topical treatments: benzyl peroxide, azelaic acid, topical antibiotics, topical retinoids, nicotinamide
Oral therapies: tetracyclines, erythromycin, trimethoprim, isotretinoin, co-cyprindol
Isotretinoin is teratogenic and has been associated with severe psychiatric side effects
What are the risk factors associated with squamous cell carcinoma?
UV light, susceptibility to UV light exposure e.g. fair skin, chemical carcinogens, HPV infection, immunodeficiency, chronic inflammation
What is the pathophysiology involved in SCC?
SCC is a malignant tumour that arises from the keratinising cells of the epidermis or its appendages. It is locally invasive and has the potential to metastasise
What are the symptoms of SCC?
A non-healing ulcer or growth in one of the higher risk sun-exposed areas, tender or painful, fast growing
What are the signs of SCC?
An indurated nodular keratinising or crusted tumour - may ulcerate, cutaneous horns can be SCC
What tests are used to diagnose SCC?
Clinical features can be the basis of diagnosis. Biopsy.
Patients with high risk SCC may need staging investigations e.g. CXR, CT scans and lymph node biopsy
What is the treatment for SCC?
Excision e.g. Mohs surgery +/- excision
What are some risk factors associated with BCC?
Sun damage, fair skin, previous cutaneous injury e.g. thermal burn, immunosuppression and a previous history of BCC
What is the pathophysiology involved in BCC?
There are often gene mutations in the patched tumour suppressor gene, may be triggered by UV exposure.
What are the symptoms of BCC?
A shiny pearly nodule, can present as a red patch of skin, nodule is often on sun-exposed areas
What are the signs of BCC?
Early lesions may have raised areas with telangiectasia, can have slightly scaly, irregular plaques
What tests are used to diagnose BCC?
Usually diagnosed clinically based on appearance.
Biopsy.
CT or MRI is indicated where bony involvement is suspected or where the tumour may have invaded the orbit, parotid gland or major nerves
What is the treatment for BCC?
Excision: excision biopsy, Mohs surgery, superficial skin surgery, cryotherapy, photodynamic therapy, imiquimod cream, 5-fluorouracil cream, radiotherapy
What risk factors are associated with melanoma?
Previous melanoma, many melanocytic naevi (moles), increasing age, fair skin, sun exposure, family history of melanoma
What is the pathophysiology involved in melanoma?
There is uncontrolled growth of melanocytes, through to begin as uncontrolled proliferation of melanocytic stem cells.
What are the symptoms of melanoma?
An unusual looking freckle or mole, can be thickened/raised, may be itchy or tender
What are the signs of melanoma?
ABCDE Asymmetry Border irregularity Colour variability Diameter >5 mm Elevation irregularity Bleeding, oozing, change in sensation
What tests are used to diagnose melanoma?
Clinical examination, dermoscopy, diagnostic excision and histology on the lesion, sentinel lymph node biopsy, investigations for metastases if suspected
What is the treatment for melanoma?
Surgical excision, chemotherapy: targeted treatments of V600 BRAF, immunotherapy and cytotoxic chemotherapy
What is the aetiology of leg ulcers?
They most commonly occur after a minor injury associated with chronic venous insufficiency, chronic arterial insufficiency, DM or HTN
What is the pathophysiology of leg ulcers?
There is full thickness skin loss and failure to heal either due to DM or due to venous stasis leading to transudation of inflammatory mediators into the subcutaneous skin and therefore breakdown of tissue
What are the symptoms of leg ulcers?
Venous: painless (unless infected) ulceration associated with aching, swollen lower legs, located below the knee
Arterial: Painful ulcer usually on the feet, heel or toes; cramp like pain on walking
What are the signs of leg ulcers?
Venous: thickened skin, hyperkeratosis, papillomatosis
Arterial: cold white/bluish shiny feet
What is the treatment of leg ulcers?
Clean the wound, debridement if necessary and dress appropriately
Venous leg ulcers can be treated with exercise, elevation at rest and compression (only compression if the patient doesn’t have arterial disease)
Possible surgical treatment of arterial disease
What are some risk factors associated with cellulitis?
DM, chronic liver disease, CKD, obesity, pregnancy, alcoholism, immunodeficiency, injury, venous disease, fissuring of toes or heels
What is the pathophysiology involved in cellulitis?
Bacteria infect the lower dermis and subcutaneous tissue.
What organisms commonly cause cellulitis?
S. pyogenes, S. aureus
Rare causes: P. aeruginosa, H. influenza
What are the symptoms of cellulitis?
Unilateral warm red skin, feeling generally unwell, blistering, fever, rigors
What are the signs of cellulitis?
Fever, peau d’orange, erosions and ulceration, abscess formation, lymphangitis, purpura (bleeding into the skin), signs of sepsis
What tests are used to diagnose cellulitis?
Diagnosis is mostly based on clinical features.
Bloods: FBC (high WCC), U&Es, LFTs, CRP (high CRP), d-dimer to rule out DVT, cultures
What is the treatment for cellulitis?
Rest and elevate affected limb, mark edge of involved area to monitor infection, analgesia, adequate fluid intake
Antibiotics e.g. penicillin G, flucloxacillin, co-amoxiclav
What are some complications of cellulitis?
Necrotising fasciitis, gas gangrene, severe sepsis
