Dermatology Flashcards
What are the seven primary functions of the skin?
Protective barrier against mechanical, thermal, chemical, and physical injury.
Prevents loss of moisture.
Reduces harmful effects of UV radiation.
Acts as a sensory organ.
Helps regulate temperature.
Functions as an immune organ to detect infections.
Produces vitamin D.
What are the key differences between UVA and UVB radiation?
UVA: Long wavelength, penetrates dermis, causes aging and skin cancer. Measured by star rating.
UVB: Medium wavelength, damages epidermal DNA, main cause of sunburn and skin cancer. Measured by SPF.
Compare basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
BCC: Most common skin cancer, slow-growing, rarely spreads, found in sun-exposed areas, also called “rodent ulcer” when it erodes.
SCC: Faster-growing, develops in keratinocytes, rarely spreads but is more aggressive than BCC.
Where do melanomas develop, and what are the common types?
Melanomas develop in melanocytes deep in the epidermis and can occur anywhere on the skin, including palms, soles, and under nails. Common types:
Superficial spreading melanoma
Nodular melanoma
Lentigo maligna melanoma
How is early-stage melanoma treated?
With surgical excision. If spread, treatment may include immunotherapy, targeted drugs, radiotherapy, or chemotherapy.
What is lentigo maligna, and why is it significant?
An early form of melanoma confined to the epidermis, often on sun-damaged skin (nose, cheeks). It has a 5% transformation risk to invasive melanoma.
What is actinic keratosis, and why is it monitored?
A scaly precancerous lesion caused by UVB damage. It can progress to SCC and requires monitoring and potential removal.
What are the causes and clinical features of impetigo?
Caused by Staphylococcus aureus and Streptococcus pyogenes, presents as red sores that burst, forming golden-brown crusts. Highly contagious.
How does cellulitis differ from impetigo?
Cellulitis affects deeper dermis and subcutaneous tissue, presenting with painful red swelling and systemic symptoms. Can be life-threatening.
What is an epidermoid cyst, and how does it present?
A slow-growing benign cyst with a central punctum, sometimes misnamed as a sebaceous cyst. It can become inflamed or infected.
What are the subtypes of eczema?
Atopic dermatitis (childhood onset, linked to asthma/hay fever).
Contact dermatitis (triggered by allergens like soap, perfumes).
Seborrhoeic dermatitis (scalp and eyelashes).
Discoid dermatitis (circular patches).
Gravitational dermatitis (poor circulation).
What are key management strategies for eczema?
Avoid triggers, use emollients, corticosteroid creams, antihistamines, and immunosuppressants in severe cases.
What factors contribute to acne development?
Androgenic hormones, bacterial overgrowth, immune activation, follicular blockage. Flares can be triggered by PCOS, medications, occlusive cosmetics, high dairy/glycaemic diets.
What is the role of isotretinoin in acne treatment?
A vitamin A derivative used for severe acne. Highly effective but contraindicated in pregnancy due to teratogenic effects.
What is psoriasis and what systemic conditions are associated with psoriasis?
- Chronic, inflammatory skin condition characterised by clearly defined, red and scaly plaques
- Immune-mediated genetic skin disease
- Can be primary, some patients have an associated health condition
- Psoriatic arthritis (auto-immune)
- Inflammatory bowel disease
- Coeliac disease
Name systemic treatments for psoriasis.
Methotrexate, acitretin, biologic therapy (adalimumab, secukinumab), ciclosporin, apremilast.
What is psychodermatology?
A subspecialty focusing on the psychological effects of chronic skin conditions. Stigma and social perception can impact mental health.
What is lichen planus, and how does it present?
An immune-mediated (T-cell) condition affecting skin, scalp, nails, genitals, and oral mucosa. It ranges from asymptomatic to severe ulceration.
What is the underlying mechanism of immunobullous diseases?
what are the most common called?
Autoantibodies attack cell connections, causing blister formation. Includes pemphigus and pemphigoid.
