Dermatology and miscellaneous Flashcards
Functions of skin? Proliferation of skin in what layer? What is desquamation? pH of skin?
Barrier to infection, thermoregulation, protection against trauma, protection against UV, via D synthesis, regulate H20 loss
Just in the basal layer
Mature corneocytes are shed from the surface of the stratum corneum- corneo-desmosomes are degraded due to proteases
5.5- proteases can remain on the skin
3 layers of skin?
Epidermis- stratum corneum= outermost made up of corneodesmosomes and desmosomes (increased in psoriasis, decreased in atopic eczema,) stratum lucidum, granulosum, spinous, basal (dividing cells)
Dermis- Meissner’s corpuscle- light touch, Pacinian corpuscle- coarse touch/ vibration
Subcutaneous tissue- fat
Cell types of epidermis?
Keratinocytes- produce keratin as protective barrier, Langerhans cells- present antigens and activate T cells, melanocytes- produce melanin which protects from UV radiation, Merkel cells- more specialised nerve endings for sensation
Common causes of itch WITH rash? With NO RASH?
Urticaria- hives, weals, welts- raised itchy rash, atopic eczema, psoriasis, scabies- burrows between fingers
Renal failure, jaundice, iron deficiency, Lymphoma- particularly Hodgkin’s, polycthaemia, pregnancy alone, drugs, diabetes, cholestasis, as skin ages- it itches more
What does acne affect? Most common variant? Epidemiology?
Hair follicle and sebaceous gland- expansion and blockage of follicle and inflammation
Vulgaris
Starts in adolescence, often resolves in mid-20s, affects face, back and chest, usually during puberty
Pathophysiology of acne?
Narrowing of hair follicles due to hypercornification blocking entrance–> increased sebum= skin feels greasy, some sebum becomes trapped in narrow hair follicle, stagnates at pit of follicle where there is no oxygen–> p.acnes multiplies–> breaks down triglycerides into free fatty acids–> irritation, inflammation and NP attraction–> pus formation and further inflammation
Presentation of acne? Diagnosis?
Whiteheads- closed comedones, blackheads= open comedones, skin-coloured papule, inflammatory lesions- closed wall of comedones ruptures, papules, pustules, nodules, commonly on face, back and chest
Usually clinical, skin swabs for microscopy and culture, hormonal tests in females
Tx of mild and severe acne?
Mild: benzyl peroxide gel/ cream= increases cell turnover, clears pores and reduces bacterial count, causes dryness, topical ABs- clindamycin gel/ erythromycin, topical retinoids e.g. tazarotene gel (irritating)= inhibit form and number of microcomedones. SEs= burning, stinging, dryness, scaling
+ topical therapy: oral tetracyclines e.g. oral doxycycline (1st line) then oral minocycline (2nd)= 4 month minimum use, CI in pregnancy and children, hormonal tx- when ABs failed/ control of menstruation is needed, anti-androgen tx= suppress sebum production e.g. oral co-cyprindiol
What does eczema/ dermatitis describe? Epidemiology? 2 types?
Common group of inflammatory skin diseases- breakdown of skin due to thinning of stratum corneum- increased risk of inflammation
Genetically complex, familial disease- strong maternal influence, 10% population, 40% episode in lifetime, high prevalence in 15-30% children and 2-10% adults, nearly always itchy
Endogenous(atopic)- usually due to hypersensitivity, exogenous- contact dermatitis usually from chemicals, sweat and abrasives
Causes of eczema? Risk factors? Pathophysiology? Presentation?
Thought to be from damaged filaggrin= skin barrier protein, exacerbated by chemicals, detergents and woollen clothes, infection either in skin/ systematically–> exacerbation by super-antigen effect
Family history- faulty gene for filaggrin
Initial TH2 activation –> inflammation
On face and flexure of limbs, itchy erythematous and scaly patches in flexure and around neck, increased dryness, infants= cheeks–> body, very acute lesions may weep/ exude and can show small vesicles, recurrent s.aureus may be common
Diagnosis of eczema? General advice? In healthy skin barrier, there are? In defective barrier e.g. in eczema?
Atopic dermatitis: clinical, high serum IgE in 80%, itchy skin condition in past 6 months + 3/ more of: history of involvement of skin creases, personal history of asthma/ hay fever, history of dry skin, onset in childhood
Education and explanation, avoidance of irritants/ allergens, keep nails short
Swelled corneocytes filled with NMF= retain moisture, lipid bilayers prevent water loss between corneocytes
Loss of NMF–> dry skin and cracks, abnormal lipid bilayer= inadequate perm barrier
In emollients e.g. E45 cream there is artificial restoration of what? Application how often? Dosage in child and adult? Compliance is significantly correlated with what?
Barrier in skin with defective barriers- trap moisture in skin and increase hydration, artificial perm barrier above stratum corneum= prevents water loss between corneocytes
Every 4 hours/ 3-4 times per day: 250-500g per week, 500-750g per week
With clinical improvement
1st and 2nd line tx for topical therapies for eczema? Classification of topical corticosteroids? What do they do? SEs?
Topical corticosteroids, topical calcineurin inhibitors
Very potent- only on thick skin- clobetasol propionate, potent- flucinonide, moderate- clobetasol butyrate, mild- hydrocortisone
Directly and indirectly inhibit pro-inflame cytokines e.g. IL-1, -2,-6 and TNF-alpha
Skin atrophy, suppression of skin barrier homeostasis, telangiectasia, thinning of skin, acne, striae, only steroids on inflamed skin!
Features of topical calcineurin inhibitors and e.g.s? Does what? SEs?
Slightly less effective- less SEs and more useful for sensitive areas e.g. pimecrolimus/ tacrolimus ointment
Inhibits calcineurin- induces trans factors for many interleukins e.g. IL-2= activate Th cells, reduce inflammation, do not cause skin atrophy
Burning, stinging following application
Tx for moderate- severe/ non-responsive?
Oral immune-modulators: ciclosporin, azothioprine, be aware of immune-suppression effects, oral steroids e.g. prednisolone, ABs e.g. flucloxacillin, phototherapy with UV A, antihistamines e.g. chlorphenamine
Sedate pt- get good rest and better sleep
What is psoriasis? Epidemiology? Risk factors?
Chronic inflammatory skin disease due to hyperproliferation of keratinocytes and inflammatory cell infiltration
2% of UK population, onset= any age- uncommon in children, peak in early adulthood, second peak= 50-60 years, equally in men and women, opposite to eczema
Polygenic, environmental triggers: infection with group A streptococcus, drugs e.g. lithium, UV light, high alcohol use, stress, family history
Pathophysiology of psoriasis? Presentation?
T-cell activation–> up regulation of TH1 cytokines e.g. interferon gamma, interleukins, growth factors and adhesion molecules–> hyper proliferation of keratinocytes in epidermis and increased cell turnover rate
Nail changes- pitting and onycholysis(separation from nail bed,) chronic plaque psoriasis: most common, well-demarcated disc-shaped, salmon-pink silvery plaques on exterior surface of limbs- elbows and knees, scalp involvement common- most at hair margin, thickened epidermis, new plaques at sites of skin trauma
Tx for psoriasis?
Emollients, topical vit D analogues: calcipqotriol cream/ ointment, topical corticosteroids- hydrocortisone cream, topical retinoids e.g. tazarotene gel, ultraviolet B, coal tar, anti-mitotic e.g. dithranol cream= large plaques only
Extensive plaques: phototherapy with UV A, DMARD= inhibits folic acid met and DNA rep, folic acid supplements 48 hrs after tx e.g. oral methotrexate- SEs= hepatotoxic, CI= pregnancy, breast feeding, hep disease/ alcoholism, renal impairment, active infection, live vaccines
Immunosuppressant- e.g. ciclosporin
3 types of psoriasis? What is fleuxural? Tx?
Flexural, guttate (raindrop-like,) palmoplantar
Later in life, well-demarcated red, glazed, non-scaly plaques, scaling= absent, flexures- groin, natal cleft and sub-mammary areas, mistaken for candida intertrigo
Hydrocortisone/ clobetasol butyrate, calcipotriol cream
Guttate psoriasis most common in who? Tx?
Children and young adults, conc on trunk, upper arms and legs
Explosive eruption of very small circular or oval plaques over trunk about 2 weeks after streptococcal sore throat
Hydrocortisone, clobetasol butyrate, ultraviolet B, coal tar
What is palmoplantar psoriasis? Tx? Anti-TNF biologics only used when?
Thickening of palms and soles
Emollients, keratolytic agents e.g. salicylic acid, flucinonide, phototherapy with UV A, oral retinoid- oral acitretin
Once systemic therapy has failed- IV infliximab, etanercept or IV adalimumab
SCC presents when? What is it? More aggressive than what? What is Bowen’s disease?
In later-life, locally invasive, malignant tumour of the squeal keratinocytes
Than BCC- higher metastatic potential, part to lymph nodes, 2nd most common below BCC
In situ SCC confined to epidermis
Risk factors for SCC? Presentation and tx?
UV exposure, chronic inflammation e.g. wound scars and immunosuppression
Most common on sun-exposed sites in later-life, lesions often keratotic- ill-defined nodules may ulcerate, can grow very rapidly, ulcerated lesions on lower lip/ ear= often more aggressive, examination of regional lymph nodes= essential for mets
Surgical excision with minimal margin of 5mm, radiotherapy also- esp if non-resectable
Most common malignant skin cancer? 95% is what? Resemble what when pigmented? Majority in who? May what? Tumour of what? Presents when?
Basal cell carcinoma Non-pigmented Melanoma In elderly on head and neck Ulcerate- 'rodent ulcer' Of the basal keratinocytes In later life Rarely mets but is locally destructive, slow-growing, locally invasive
RFs for BCC? Presentation and tx?
UV exposure, skin type 1L burns and doesn’t tan, ageing
Border of ulcerated lesions raised with pearly appearance
Slowly enlarging, shiny nodule on head and neck- bleeds following minor trauma and does not heal
Slowly–> local tissue destruction if not treated
Surgery excision with wide borders and histology- ensure clear and adequate tumour margins
Superficial= non-surgical- cryotherapy, photodynamic therapy, radiotherapy cannot tolerate surgery