Dermatology Flashcards
Dermatology - do for finals revision, prob only time for questions unfortunately
What is the management of hyperhidrosis?
- Topical aluminium chloride. SE: skin irritation
- Iontophoresis: esp if palmar/plantar/axillary
- Botulinum toxin: axillary sx
- Surgery e.g. transthoracic sympathectomy. Make aware risk of compensatory sweating
What are the stages of wound healing?
- Haemostasis – vasoconstriction + platelet aggregation, clot formation
- Inflammation – vasodilatation, migration of neutrophils + macrophages, phagocytosis of cellular debris + invading bacteria
- Proliferation – granulation tissue forms by fibroblasts, angiogenesis, then re-epithelialisation (epidermal cell proliferation + migration)
- Remodelling – collagen fibre re-organisation, scar maturation
Pathophysiology acute allergy
- Trigger like foods, drugs, insect bites, contact, sweating, idiopathic - immunological or non-immunological
- Inflammatory mediators released from mast cell degranulation - major one is histamine
- Vasodilation + increased capillary permeability
Urticaria
Swelling of superficial dermis - pruritic wheals, which are described as erythematous plaques, some discrete + found, some confluent
- Acute: infection or type 1 allergy, localised/widespread progressing to anaphylaxis
- Chronic: >6w, may be spontaneous autoimmune cause or inducible from friction/cold/sun etc
M:
- Acute usually self-resolves
- If a/w anaphylaxis obv treat for this with 500 micrograms adrenaline 1:1000 IM + 200mg hydrocortisone + antihistamine
- Chronic causes non-sedating anti-histamines
- Steroids if severe
- Avoid NSAIDs + opiates - may aggravate
Angioedema
Deeper dermal + SC swelling causing tongue + lip swelling
- May be with urticaria
- May be without urticaria: hereditary (rare) or acquired (idiopathic or lymphoproliferative disease/autoimmune/some drugs e.g. ACEi)
- Angioedema alone - corticosteroids
- With anaphylaxis - adrenaline 500 micrograms of 1:1000 IM + 200mg hydrocortisone + antihistamine
- Comps: asphyxia, cardiac arrest
Erythema nodosum
Hypersensitivity response in dermis + SC - to Strep, TB, pregnancy, cancer, sarcoidosis, IBD, chlamydia, drugs (OCP, sulfonamides, NSAIDs)
Most common in YA females
Discrete tender nodules usually over shins, may be confluent, appear over 1-2w, leave bruise-like discolouration as resolve over 2-3w, dusky blue/red colour, no atrophy/scarring/ulceration
*May get fever, malaise, arthralgia
No treatment for it just rest, NSAIDs for pain
Erythema multiforme
Acute self-limiting inflammation, precipitated by HSV/other infection like Mycoplasma/drugs like COCP penicillin sulphonamides NSAIDs allopurinol/unknown
Classically target lesions on back of hands/shins then spreads to torso, lesions may blister, with no mucosal involvement (or only 1 mucosal surface - if mucosa involved erythema multiforme major), sometimes mild pruritus, UL>LL
Stevens Johnson syndrome
Mucocutaneous necrosis triggered by drugs/infection with at least 2 mucosal sites involved, varying skin involvement, leads to epithelial necrosis with few inflammatory cells
Unusual-looking target lesions
M: call for help, supportive, monitor for sepsis/electrolyte imbalance/organ failure
Toxic epidermal necrolysis
Usually secondary to a drug reaction causing extensive skin + mucosal necrosis with systemic toxicity. Full-thickness epidermal necrosis + sub epidermal detachment
Drug causes: phenytoin, sulphonamides, allopurinol, penicillins, carbamazepine, NSAIDs
M: stop cause, higher mortality than SJS, ICU for supportive, IV Ig often given or other immunosuppressive
Rash of meningococcal sepsis
- May begin as blanching maculopapular rash
- Develops to non-blanching purpuric rash on trunk + extremities
- May develop ecchymoses, haemorrhagic bull + tissue necrosis
Erythroderma
Exfoliative dermatitis of at least 90% of skin surface
Cause: eczema, psoriasis, drugs (sulfonamides, gold, sulfonylureas, penicillin, allopurinol, captopril), idiopathic, lymphoma/leukaemia, pemphigus foliaceus, HIV
Skin: inflamed, oedematous, scaly, feels tight + itchy to pt, long-standing causes hair loss/ectropion of eyelid/nail shedding
Systemic: malaise, fever/chills, lymphadenopathy
M: cause if known, emollients + wet wraps to maintain skin barrier, topical steroids, supportive like fluids, swab skin if suspect infection, stop non-essential drugs
Comp: infection, fluid loss/electrolyte imbalance, hypothermia, high output HF, AKI, low albumin + capillary leak syndrome (can lead to hypovolaemic shock + ARDS)
Eczema herpeticum
Complication of atopic eczema/other conditions triggered by HSV
Extensive crusted papules, blisters, erosions, a/w fever + malaise
M: antivirals + Abx if bacterial secondary infection
Can lead to herpes hepatitis, encephalitis, DIC or death
Necrotising fasciitis
Rapidly-spreading infection of deep fascia + tissue necrosis, due to group A haemolytic strep/anaerobes. Half occur in otherwise healthy people
Severe pain, erythematous blistering necrotic skin, fever + tachycardia, subcutaneous emphysema (crepitus), may have soft tissue gas on XR
M: extensive surgical debridement + IV Abx. Mortality up to 70%
Burns
- Classification: superficial epidermal (red + painful), partial thickness/superficial dermal (pale pink, blistered, painful), partial thickness/deep dermal (white/patches of non blanching erythema, reduced sensation), full thickness (white/brown/black, no blisters, no pain)
- Wallace’s rule of 9-each of these are 9% of body surface area: H+N, right arm, left arm, anterior right leg, anterior left leg, posterior right leg, posterior left leg, anterior chest, posterior chest, anterior abdomen, posterior abdomen
- Refer to secondary care any deep dermal/full thickness, superficial of >3% TBSA (or 2% in kids) or if they involve hands/feet/face/perineum/flexure, or if inhalation/electrical/chemical or suspecting NAI
- Superficial epidermal: analgesia, emollients
- Superficial dermal: clean, leave blister, non-adherent dressing, avoid creams, r/v in 24h
- Severe burns: stop burning process, refer complex ones to specialist unit, circumferential e.g. around torso may need escharotomies to divide the burnt skin to improve ventilation/compartment syndrome, excision + grafting
- IV fluids in adults >15% burns/children >10% using Parkland formula
- Comps of burns: dehydration as fluid lost into 3rd space, catabolic, immunosuppression e.g. bacterial translocation from gut lumen, sepsis
Cellulitis + erysipelas
Spreading bacterial infections: cellulitis involves deep SC tissue, erysipelas more superficial (dermis + upper SC). RF are immunocompromised, wounds, intertrigo in toe webs
Causes: Strep pyogenes, Staph aureus, gram neg in immunocompromised
CF: oedema, erythema, warmth, pain, lymphangitis, sometimes localised blistering/necrosis, systemically unwell (esp erysipelas)
- Erysipelas more common on face + has more well-defined border
- Cellulitis most common on LL/arm
- Skin swabs usually negative unless taken from broken skin
- Can cause local necrosis, abscess or sepsis
M: flucloxacillin/erythromycin, sterile dressing, analgesia
Staphylococcal scalded skin syndrome
Toxin from some strains of staph (e.g. bullous impetigo) - widespread desquamation over hours-days, most common in young children (if in adults more likely immunosuppresed). Often in armpits/groin/orifices then spreads, in newborns umbilical/nappy area. Can get outbreaks
Scald-like appearance, large flaccid bulla, perineal crusting, intra-epidermal blistering, v painful
M: IV anti-staph like flucloxacillin (erythromycin if allergic), paracetamol, skin care e..g petroleum, hydration + electrolytes, recover in 5-7d
If untreated can lead to pneumonia and sepsis
Impetigo
V contagious S aureus/Strep pyogenes infection, direct spread
Causes inflamed plaques, golden crusted surface, often around mouth + nose; bullous form from certain staph strains
M: topical fusidic acid if localised, oral flucloxacillin/erythromycin/clarithromycin if widespread, avoid school/work until lesions dry/48h after Abx
Folliculitis
Hair follicle infection, usually S aureus. RF: humidity, obesity, DM
Causes pruritic/tender papules + pustules
M: topical antiseptics or Abx or oral Abx
Furuncles
Boils - deep infection of hair follicles, usually S aureus
Painful red pus-filled swellings, multiple are ‘carbuncles’
M: hot bathing, if widespread/on face try oral fluclox/erythro/clarithro for 10-14d
Erythrasma + pitted keratolysis
Erythrasma: orange/beige rash in large flexures caused by a bacteria, commensal overgrowth, M with topical erythromycin + antiperspirants
Pitted keratolysis: superficial infection of horny layer of skin, small punched out circular lesions on macerated skin, M-topical Abx + antiperspirants
Herpes simplex of skin
HSV-1 can sometimes cause painful blisters/gingivostomatitis, or may inoculate into trauma sites causing painful pustules (e.g. herpetic whitlow on fingers)
M: cold sores-topical acyclovir, oral antiviral prophylaxis if recurrent
Viral exanthem
Most common skin manifestation of a virus
Erythematous maculopapuler rash mostly on torso + proximal limbs - prob immune complex deposition in dermal bvs
Then there are the specific viral rashes from paeds
Shingles
Reactivation of latent VZV:
- Prodrome of tingling/pain
- Painful u/l blistering eruption in dermatomal distribution (can be multiple), in crops, may be purulent then crust, lasts 1-2w
- M: Analgesia, oral acyclovir if given early, high dose IV aciclovir if immunosuppresed
- Comps: post-herpetic neuralgia, ocular, motor neuropathy
Human papilloma virus
- Common warts: papules with coarse surface, often have small black dots (vessels) within, direct spread
- Plantar warts - verrucae. Warty papillomatous appearance but flat as on foot
M: often take months-years to clear, may try removal of hyperkeratotic skin with salicylic acid, or cryotherapy
Molluscum contagiosum
- Poxvirus, transmitted by close contact or via contaminated surfaces like towels
- Majority occur in children esp with eczema
- Multiple small translucent/pink/white papules, firm, soft white matter inside (can squeeze out), central umbilicated depression. Trunk + flexures in children, may get anogenital, in adults sexual contact may cause them on genitalia/thighs/lowr abdomen
- M: reassure, resolve in 18m, avoid sharing towels + baths etc, don’t need exclusion from anything, don’t scratch, treatment usually not recommended
- If problematic: can try squeezing after bath, localised trauma like cryo, emollient + mild topical steroid for itch, topical abx like fusidic acid if looks infected (oedema, crusting)
- If HIV + extensive lesions urgently refer (sign of more disease), if around eye refer to ophthalmology, if anogenital in adults refer to GUM
Orf
Pox virus of sheep/goats - can catch from petting stations - red papules with inflamed border that blisters/turns into pustules, resolve in 4-6w
Dermatophyte skin infection
‘Ringworm’ infections as tend to form expanding annular lesion, usually u/l + itchy + asymmetrical, scaly edge.
Don’t give topical steroids! Try antifungal cream like clotrimazole/terbinafine or if widespread oral antifungal
*Tinea corporis: trunk + limbs
*Tinea pedis-athletes foot. moist scaling + fissuring in toe webs, skin white/macerated, may flare as blisters/pustules, no annular lesions
*Tinea capitis: scalp ringworm, spread by close contact, causing scarring alopecia mostly kids, kerion (raised pustular boggy mass), exaggerated inflammatory response with pustules. M-ketoconazole shampoo + oral anti fungal
*Tinea manuum of hand: scaling + dryness in palmar creases
*Tinea crunis of groin, v pruritic
*Tinea unguium-of nail
*Tinea incognito-inappropriate treatment with steroids causing ill-defined lesions
Onychomycosis
Fungal nail infection - tinea unguium (dermatophyte infection), usually toenails, more common with age + DM
CF: dystrophic, rough, opaque thickened nail, discoloured white/yellow/beige, usually begins distally/lateral then spreads
M: clip back, 3-6m of oral itraconazole/terbinafine once clippings confirm
(if caused by candida mild topical anti fungal is used)
Candida albicans
Commensal yeast in GIT that may overgrow on occluded moist skin
- Candidiasis: white plaques on mucosal areas, erythema with satellite lesions in flexures
- Intertrigo of large flexures: irritation, sore, inflamed, ragged peeling edge, may have pustules + satellite lesions
- Paronychia: chronic nail fold infection from frequent immersion
Usually topical azoles or nystatin
Pityriasis versicolor
Due to Malassezia (a yeast commensal)
Scaly pink-brown patches/macules on upper trunk, hypo pigmented (don’t tan), asymptomatic/mild pruritus
M: topical azoles (ketoconazole shampoo) or if fails send scrapings + oral itraconazole. takes months for pigment to change
it can also cause a type of folliculitis
Scabies
Mite infestation spread by close contact
- Intensely pruritic excoriated rash, small red papules/vesicles anywhere but usually not face (esp webs, palms + soles, axillae, nipples, umbilicus, male genitalia), linear/curved burrows
- M: topical scabicide e.g. permethrin overnight to all skin below the neck + under nails, treat all close contacts at same time even if asymptomatic, repeat after 1w, wash everything at 60 degrees. may also use malathion
- Pruritus may stay for up to 6w
- Crusted scabies: variant in immunosuppressed with huge numbers of mites, mild/absent pruritus, v infectious, hyperkeratotic crusted plaques + widespread erythema. Barrier nursing, repeated scabicide treatment
Lice
- Head lice pediculosis capitis: pruritus, excoriations, papules around hairline of neck + ears. Wet combing until all eggs hatched
- Body lice pediculosis corporis: disease of poverty + neglect with itch, excoriations, post-inflammatory hyperpigmentation, use permethrin/malathion
- Pubic lice/crabs - Phthiriasis pubis: itching, see near base of hair with eggs further up
Insect bites
Papular urticaria caused by arthropods - itchy urticarial lesions, often in clusters, may blister in hot weather, some people react badly to them
Bed bugs: emerge from seams of bedding at night, clustered itchy papules on exposed areas. need property to be treated
Acute vs chronic eczema features
Acute: vesicles/bullae within oedematous inflamed skin, scratching causes exudate + crusting
Chronic: dry, lichenification
What are the types of eczema/dermatitis?
- Atopic
- Seborrhoeic: v common in greasy areas, causes scaling + erythema, may itch, e.g. dandruff (mildest form on scalp), prob triggered by a commensal yeast. chronic course, topical azoles/shampoos
- Discoid: well demarcated inflamed scaly patches, v itchy, potent topical steroids to clear
- Asteatotic: affect elderly in winter, can be v pruritic, affects dry areas with scales/inflammed fissures. M-soap substitute, emollients
- Chronic hand/foot eczema: common, contact dermatitis or no external cause, dry skin esp in people who wash hands a lot
- Venous: usually in elderly people with h/o varicose veins/venous thrombosis, can be mild erythema + scale or acute exudative rash, signs of venous insufficiency. M: short term moderate steroid, may benefit from compression if ABPI ok, emollients
- Irritant/allergic contact dermatitis: delayed hypersensitivity 12-24h after contact, manage active eczema + minimise contact
- Lichen simplex: chronic eczema where skin is lichenified from rubbing, M-topical anti pruritic + short term potent steroid
- Nodular prurigo: persistent itchy nodular eruption, eroded hyperkeratotic nodules
Cause of atopic eczema
Usually develops in early childhood + resolves during teenager years tho may recur
- Related to a FH of atopy, may have genetic defect in skin barrier
- Often raised IgE - cause or effect?
- Exacerbated by infections, allergens, sweating, heat, severe stress, wool; no clear link with food (young children often get type 1 hypersensitivity to foods but eczema is rare)
Features of atopic eczema
- Itchy erythematous dry scaly patches with papules + vesicles
- Infants: more common face + extensors
- Children+adults: more common neck/flexors
- Acute lesions - erythematous, vesicular, exudative
- Chronic itching - excoriations + lichenification, post-inflammatory hypo/hyperpigmentation
- May also have nail pitting + ridging, thickened skin, prominent palm creases, ichthyosis vulgarisms
Management of atopic eczema
- Education, avoid known precipitants, only alter diet with expert supervision in infants, emphasise importance of emollients +/- bandages in younger kids, bath oil/soap substitute (avoid soaps!)
- Topical steroids for flares: usually od/bd to inflamed areas, milder like hydrocortisone for face, don’t skimp
- Topical immunomodulators like calcineurin inhibitors e.g. tacrolimus ointment. Benefits are dont cause skin atrophy so good for delicate areas, but poorer penetration of thickened areas, ADR-burning when first use but improves, alcohol induced flushing, higher risk skin cancer
- Topical antiseptics may be added to bathwater if recurrent infection but they’re irritant
- Oral antihistamines, sedating if sleep affected, for itch
- Treat viral/bacterial infections
- Severe cases: phototherapy, immunosuppression with prednisolone/azathioprine/ciclosporin
Complications of atopic eczema
- Bacterial infection - S aureus or strep. Crusted papules/pustules + exudate
- Viral: molluscs, warts, eczema herpeticum
- Eye comps: conjunctival irritation, keratoconjunctivitis
Cause of psoriasis
Chronic inflammatory disease with hyper proliferation of keratinocytes + inflammatory cells, related to genetic, immunological + environmental factors
Precipitated by trauma, infection, drugs (lithium, BBs, antimalarials, NSAIDs, ACEi, TNF alpha inhibitors), stress, alcohol
Types of psoriasis
- Chronic plaque psoriasis (most common)
- Guttate: ‘raindrop lesions’, v small circular/oval papules mostly over trunk + prox limbs, red-pink, more in children/YA, a/w Strep sore throat. Most go within 2-3m, may give topical steroids/phototherapy if symptomatic but guidelines are not to give Abx. May be 1st presentation of psoriasis or exacerbation of plaque psoriasis
- Seborrhoeic in naso-labial folds/behind ear
- Flexural in body folds, usually red glazed plaques without scale, M-mild steroid/tar or tacrolimus
- Pustular and erythrodermic: severe types with sterile pustules of inflammatory fluid, needs very potent topical steroids
- Palmoplantar pustular psoriasis: localised inflammatory pustules but without systemic sx, a/w smoking
Features of plaque psoriasis
- Pink-red, well-demarcated plaques with silver scale
- May itch, burn or pain
- Nail changes: pitting, onycholysis, yellow-brown discolouration, subungual hyperkeratosis
- Mostly extensor surfaces, lower back, ears, scalp
- Kobner phenomenon: new plaques appear at sites of trauma
- Psoriatic arthropathy around 5% (so always ask about): symmetrical polyarthritis/asymmetricalmonoarthritis, lone DIP disease, psoriatic spondylosis, flexion deformity of DIPJ
- Higher prevalence of metabolic syndrome cos of chronic inflammation
Comps: erythroderma, psychological/social effects
Management of psoriasis
- General: avoid precipitants, emollients to reduce scale, explain no cure but can manage
- Topical therapy for mild disease: mild steroid for face, potent steroid for rest of body; if no improvement in 8w offer vitamin D analogue (e.g. calcipotriol which reduce cell division to reduce the scale + thickness); if no improvement try using steroid BD or add coal-tar preparations (inhibit DNA synthesis); may add diathranol
- Phototherapy for extensive: UVB light, or photochemotherapy with UVA + psoralen
- Oral treatment for extensive or severe/systemic involvement: methotrexate, retinoids like acitretin, ciclosporin, mycophenolate mofetil, biologicals like infliximab/etanercept
Venous leg ulcers
Large shallow irregular ulcer, painless, exudative granulating base, malleolar area (esp above the medial malleolus)
- Peripheral pulses present, warm skin, normal ABPI
- A/w oedema, haemosiderin deposition, lipodermatosclerosis, atrophie blanche (white scarring + dilated caps)
- M: compression bandaging usually 4 layer (only thing shown to benefit)
Arterial ulcers
Painful, small sharply-defined deep ulcer, necrotic base, at pressure or trauma sites + distal areas like toes.
- Cold skin, weak/absent peripheral pulses, shiny pale skin, loss of hair
- ABPI <0.8 indicates insufficiency, do Doppler + angiography
- M: vascular reconstruction
Neuropathic ulcers
Abnormal sensation from DM/neuro disease so often don’t notice. Lesion of variable size with granulating base, may be around a keratotic lesion like a callus, occur at pressure sites
- Warm skin, normal pulses unless neuro-ischaemic
- XR to exclude osteomyelitis
- M: wound debridement, regular repositioning, good footwear, nutrition
Lichen planus
Chronic inflammation of unknown cause, lichenoid-like rashes may be triggered by ACEi/antimalarials/BBs/gold
- Clusters of pruritic purple-pink polygonal papules, with Wickham’s striae (fine lacy white streaks)
- Most common wrist/LL but can be anywhere
- May fuse into plaques + become hyperkeratotic, may cause post-inflammatory hypopigmentation, may cause a scarring alopecia or involve nails causing a permanent dystrophy, may have Koebner phenomenon
- 50% have mucosal involvement: white reticular streaks on buccal mucosa, gingivitis, glossitis, anogenital
- M: resolve in 1-2y, rarely can change to SCC, topical steroids/tacrolimus can help, oral mucosa-mouthwash, severe-oral immunosuppressants
Granuloma annulare
Child/YA, self-limiting goes in 2y, usually asymptomatic + cause unknown – small flesh-coloured/erythematous papules, form rings with a dusky centre, often on dorsum of hand/foot
Lichen sclerosus
Common inflammatory dermatosis usually at genitals, usually affects females before puberty/after menopause, or males at any age. Increase risk of vulval/penis SCC, can lead to scarring/atrophy which may impede micturition/sexual function. White plaques form due to epidermal atrophy
CF: pruritic/sore shiny/white fissured patches, perianal involvement common (figure of 8 distribution), may have telangiectasia, children may have haemorhagic bullae, can lead to balanitis in males
M: v potent topical steroids + emollients, in children more likely to remit spontaneously, FU women as higher risk of vulval cancer
*Adv biopsy if suspect neoplastic changes e.g. new lesions, erosions, unresponsive to steroids, pigmented areas