Intro to dermatology Flashcards
What are important things to ask in a dermatological history of the presenting complaint?
Initial appearance of lesion and evolution
Recent contact at site with animals, any recent illness or travel
History of sunburn or self-tanning machines
Relieving factors and what makes it worse
Anything similar or other skin conditions in the past
Occupation
Impact of lesion on life
What is a naevus?
Localised tissue malformation where there is a cluster of melanocytes to form a mole
What is pruiritus?
Itching
What is a lesion?
Altered area on skin
How is the skin examined?
1) Inspect
2) Describe
3) Palpate
4) Systemic check of body, all organ systems, and temperature
What do we look for in an inspection?
Site of lesion, number of lesions
Pattern of distribution and configuration (arrange).
What can be used for inspection?
Dermoscopy to view melanomas and Wood lamp of UV rays to identify infections and pigmentation
What is skin examined for?
SCAM
S-size and shape
C- Colour
A-Associated secondary change
M- Margin and morphology
How is a pigmented lesion examined?
ABCD
A: assymetry
B: border
C: colour
D: diameter
What is flexural?
Distribution is located in the body folds such as the antecubital and popliteal fossa, neck and groin
What is an erythrodermic distribution?
Generalised spread mostly all over the body’s skin surface
What is examined in palpation?
Surface, consistency, mobility, temperature and tenderness
What are the common inflammatory dermatoses?
Acne
Atopic eczema
Psoriasis
What is acne?
Chronic inflammatory condition of the pilosebacous unit which affects the face, chest and back primarily. Characterised by seborrhea (excessive oiliness)
Why does acne occur?
Hypertrophy of the pilosebaceous gland due to hgh levels of androgens or inflammation leads to excess sebum production. There is an obstruction to release due to hyperkeratinisation which leads to build up and formation of comedone. This causes inflammation lesion of pustule or papule which ruptures and leaves scarring
What is the role of the pilosebacous gland?
Lubricates hair and provides pathogen defence. Contains the commensal bacterium propiobacterium
How does acne develop?
Begins as a non-inflammatory lesion of open and closed comedone that ruptures and becomes inflammatory lesions of papules and pustules
What are the types of acne lesions?
Comedones, superficial lesions of papules and pustules and deep inflamed lesions called nodules.
What are nodules?
SOlid lumps located in dermis or subcutis which occur in severe acne. They are not always visible and are generally tender and painful and occur in arthritis.
What is telangieactasia?
Raised blood vessels on skin surface.
What is a macule?
Flat discoloured area on skin.
What is a papule?
Slightly raised patch of skin which is palpable, caused by acne, hormonal changes or bacteria.
What is a plaque?
Area of skin which is thickened, that occurs in psoriasis.
What is a pustule?
Small bulge of skin filled with pus deeper into the skin caused by acne or smallpox.
What is a cyst?
Progression from a pustule where pocket of skin becomes hard and painful and may grow in size, filled with pus.
What is a comedone?
Pores or hair follicles which have become clogged with bacteria, sebum or dead skin cells to form what is called a hardened bump called a whitehead or blackhead
What are open comedones?
Blackheads where oxidisation of sebum and filled with melanin and are enlarged
What are closed comedones?
Whitehead which are small and non-inflamed
What are the types of acne scars?
Atrophic: heals below epidermis
Hypertrophic: overgrowth of fibrous tissue on epidermis
What is eczema?
Caused by genetic mutation of the filaggrin protein in the epidermis which allows entry of allergnes. IgE-mediated hypersensitvity and TH2 responds by releasing cytokines to recruit TH1 which characterises it as an autoimmune condition. Eosinophils are recruited which induce inflammation. Keratocytes in the skin release TSLP which contribute to itching. Eczema leads to thickening of the dermis and red patches caused by inflammation.
Where does eczema present in infants?
Extensor parts of limbs
Where does eczema present in adults?
Flexor parts of limbs
How does eczema present?
Itchy erythematous scaly plaques.
Acute lesions are exudative, erythematous and vesicular
Chronic lesions lead to excoriations and lichenification
What is excoriation?
Lesions caused by picking at the skin which is a mental health condition
What is lichenification?
Secondary skin condition where there is hyperpigmentation and thickening of the skin due to excessive itching caused by eczema
What are vesicles?
Small clear fluid filled blisters which are typically numerous.
What is a bulla?
Large clear fluid filled blister
What is psoriasis?
Combination of genetic and inflammatory environmental factors with hyperproliferation of keratinocytes in the skin and inflammatory cells infiltration which build up on skin surface results in scaly erythamatous plaques.
What are the factors that occur before psoriasis?
Trauma, infection, drugs, stress, alcohol
What is a plaque?
Palpable thick raised lesions on the skin that occurs in eczema and psoriasis.
What are the complications of psoriasis?
Erythroderma distribution which can lead to secondary infection, fluid loss and electrolyte imbalance and hypothermia and Koebner phenomenon
What is the Koebner phenomenon?
A linear eruption on previously unaffected skin
What is desquamification?
Shedding of the skin
What is an erythema?
Redness of the skin caused by inflammation and vasodilation due to injury or immune condition which blanches upon pressure
What is petechia?
Small pinpoits of haemorrhage which don’t blanch. caused by thrombocytopenia
What is purpura?
Red or purple spots/patches that occur due to trauma or vasculitis in the skin, lesser caused by thrombocytopenia.
What is proopiomelanocortin?
A molecule derived from ACTH along with melanocyte stimulating hormone. When ACTH levels rise in Addison’s disease, due to adrenal gland destruction, it increases production of these pigmenting molecules.
Where is melanocyte stimulating hormone secreted from?
Corticotroph region of adrenohypophysis which causes increase in melanin production from melanocytes and suppresses appetite.
Why do pigmentation issues occur?
Due to inflammation or UV exposure which alters melanocyte production of melanin
What are the types of bacterial infection?
Staphylcoccal and streptococcal
What are the erythrasma?
Dark patch which is a Common skin condition of the skin folds due to gram positive cornyebacterium minitussimum with patches and scaling.
What is zoster virus?
Zoster virus affecting distribution of the trigeminal opthalamic nerve
What are the types of skin cancer?
Non melanoma such as basal cell carcinoma and squamous cell carcinoma
Melanoma
What is the most common skin cancer?
Basal cell skin cancer. It has uncontrolled local proliferation of basal cells to form a malignant tumour.
It is slow growing and rarely metasases. Most common in the head and neck.
What causes basal cell skin cancer?
UV exposure, history of frequent sunburn, male, increasing age. The cancer is usually ulcerated with telengactasia.
How does basal cell skin cancer present?
Nodular with an ulcerative or necrotic centre
Superficial plaque like
What is squamous cell skin cancer?
Second most common skin cancer with abnormal proliferation of keratinocytes in the stratum spinosum due to UV radiation, so occurs in the head and neck.
Appears as scaly red patches or firm nodules and more commonly metastasise compared to BCC, and this is to the lymph nodes.
How does squamous cell skin cancer present?
Scaly red patches, open sores and thickened sores. Lesions arise in sun exposed areas
What is a malignant melanoma?
Invasive malignant tumour of epidermal melanocytes which commonly metasases to the skin and lungs. It has the highest mortality rate and most common cancer in young adults
What are the risk factors for melanomas?
Excessive UV exposure, type 1 skin that burns not tans, history of moles, immunosuppression.
What are the features of melanoma?
Pigmented with ill-defined borders, assymetrical. When severe, it can bleed
What is superficial spread melanoma?
Prominent in young people on the lower limbs and back due to intermittent high UV exposure
What is nodular melanoma?
Prominent in younger adults on the trunk and appears as a mole due to intermittent High UV exposure.
What is lentigo maligna melanoma?
Early melanoma confined to the epidermis due to long term UV exposure, more common in elderly..
What is acral lentigous melanoma?
Melanomas present on the soles of feet, palms and nails as a dark macule in elderly population, especially south Asians and Africans.
What is Breslow depth?
Depth of tumour from most superficial to deep
What is the process of Vitamin D formation in the body?
Synthesised by sunlight/taken by diet as 7-dehydrocholesterol -> cholecalciferol Vitamin D3 by keratinocytes along with D2 ergocalciferol. This is hydroxylated by the liver to form 25 (OH) d3 and hydroxylated again by the kidney via PTH to form calcitriol 1,25 (OH)2 D3.
What is the role of keratin?
Maintain hydration
What type of epithelia is the stratum basale?
Cuboidal epithelia
Where are Langerhaan cells most present?
Stratum spinosum
What is the stratum lucidum?
Found between corenum and granulosum in thick skin
What is the granulosum layer?
Granulohyalin granules of keratin with lamellar bodies
Immune cells of dermis?
Reticular dermis contains mast cells and macrophages
