Dermatology Flashcards
Stevens-Johnson syndrome hypersensitivity type and most significant RF
Type 4
HIV x100
Causes of stevens johnson syndrome
Abx (penicillin, sulphonamides - sx within 1 wk), AEDs (lamotrigine, carbamazepine, phenytoin - within 2 months), allopurinol, NSAIDs, oral contraceptives
Features of steven johnson syndrome
Prodromal fever, myalgia, sore throat, then after a few days maculopapular, target lesions (may develop into vesicles/bullae, Nikolski’s +ve), mucosal involvement, arthralgia.
HLA assx with SJS
HLA B*1502 - carbamazepine-induced SJS+TEN in Han Chinese
Erythema multiforme features
target lesions, initially on back of hands/feet, then spread to torso, upper > lower limbs, mild pruritis common
Features of erythema multiforme major
mucosal involvement, more severe
Causes of Erythema multiforme
viruses (HSV), Orf (parapox), idiopathic, mycoplasma, streptococcus, penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptives, nevirapine, SLE, sarcoidosis, malignancy
Features of TEN
life-threatening. Scalded appearance over extensive area.
systemically unwell, +ve Nikosky’s sign (epidermis separates with mild lateral pressure)
Causes of TEN
Abx (penicillins, sulphonamides), AEDs (carbamazepine, phenytoin), allopurinol, NSAIDs. Rx: stop precipitating factor, supportive care (ICU), IVIG, immunosuppressants, plasmapheresis
Scoring system for hirsutism
Ferriman-Gallwey scoring system (Severe >15).
What is hirsutism driven/dependent on/by
androgens
Causes of hirsutism
PCOS (most common), Cushing’s, CAH, Androgen therapy, Obesity (insulin resistance culprit), adrenal tumour, androgen secreting ovarian tumour, phenytoin, steroids.
Rx for hirutism
weight loss, COCP (co-cyprindiol - Dianette - has VTE risks; ethinylestradiol and drospirenone - Yasmin), topical eflornithine for facial hirsutism (contraix in pregnancy, breast-feeding)
Hypertrichosis - is it dependent on androgens?
no - androgen independent
Causes of hypertrichosis
minoxidil, ciclosporin, diazoxide, congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis, PCT, anorexia nervosa
What is onycholysis
separation of nail plate from nail bed.
Causes of onycholysis
DIRT PIT
dermatitis, idiopathic, Raynaud’s, Trauma (excessive manicuring), Psoriasis, Infections (fungal), Thyroid disease (hyper/hypo)
Causes of impetigo
S aureus, S pyogenes,
Primary or 2 to eczema, scabies, insect bites.
Features of impetigo
Common in children, esp in warm weather. Often on face, flexures, limbs. Incubation period 4-10 days. Golden, crusted skin lesions, very contagious (spread via direct + indirect contact).
Rx for impetigo
hydrogen peroxide 1% if not systematically unwell or high risk, or topical fusidic acid (topical mupirocin if fusidic resistance suspected or MRSA). Flucloxacillin (erythromycin if pen allergic) if extensive. School exclusion 48hrs after abx start or until lesions crusted + healed
Skin manifestations in TB
lupus vulgaris (50% of cases, occurs on face, nose, mouth, initially erythematous flat plaque, becomes elevated, may ulcerate later), erythema nodosum, scarring alopecia, scrofuloderma (breakdown of skin overlying TB focus), verrucosa cutis, gumma
Erythema nodosum causes
Strep, TB, brucellosis, sarcoidosis, IBD, behcet’s, malignancy/lymphoma, penicillins, sulphonamides, COCP, pregnancy.
Erythema nodosum features
Symmetrical, erythematous, tender nodules, heal without scarring
Types of contact dermatitis and their features
Irritant: common, non-allergic, weak acids/alkalis. Often on hands, erythematous. Rarely crusting/vesicular
Allergic: Acute weeping eczema predominantly affecting hairline margins than hairy scalp itself.Rx: topical potent steroids.
What type of contact dermatitis can cement cause
Cement can cause both irritant (alkaline nature of cement) + contact (dichromates in cement)
Pretibial myxoedema features
symmetrical, erythematous lesion seen in Grave’s, shiny, orange peel skin
Antibodies in pemphigus vulgaris
anti-desmoglein 3
Features of pemphigus vulgaris
Ashkenazi Jewish. Flaccid blisters, easily ruptured vesicles, bullae. Painful but not itchy. oral (50-70%), mucosal ulceration, nikolsky’s +ve (spread of bullae following horizontal, tangential pressure), acantholysis on biopsy,
Rx for pemphigus vulgaris
steroids
immunosuppression
Bullous pemphigoid antibodies
anti hemidesmosomal proteins BP180, BP230
Features of bullous pemphigoid
More common in elderly. Itchy, tense blisters around flexures, usually heal without scarring.
Stereotypically no mucosal involvement (actually 10-50% have some mucosal involvement).
How to investigate/diagnose bullous pemphigoid
skin biopsy - immunofluorescence showing IgG and C3 at dermoepidermal junction
Rx for bullous pemphigoid
derm referral for biopsy, oral steroids, topical steroids, immunosuppressants, abx can be used too
Pyoderma gangrenosum features
Neutrophilic dermatosis (dense neutrophil infiltration in affected tissue on biopsy).
Sx: Initially small red papule, later deep, red, necrotic ulcers with violaceous border, typically on lower limb, may be accompanied with fever, myalgia.
May be seen around stoma site
Rx for pyoderma gangrenosum
steroids (oral)
Causes of pyoderma gangrenosum
Idiopathic in 50%, IBD (10-15%), Rheumatological (RhA, SLE), Haematological (Myeloproliferative, lymphoma, myeloid leukaemia, IgA monoclonal gammopathy), GPA, PBC
Skin disorders in diabetes
LOVINNG LipOatrophy, Vitiligo, Infections (strep, staph, candida), Necrobiosis lipoidica diabeticorum, neuropathic ulcers, granuloma annulare
Features of necrobiosis lipoidica diabeticorum
shiny, painless areas of yellow/red skin typically on shins of diabetics, often associated with telangiectasia
Features of granuloma annulare
papular, slightly hyperpigmented, depressed centrally, on dorsal surfaces of hands, feet, extensor surfaces of arms, legs.
Associations for vitiligo
T1DM, Addison’s, Autoimmune thyroid, pernicious anaemia, alopecia areata.
Features of vitiligo
loss of melanocytes, depigmentation
Trauma may precipitate new lesions (Koebner’s), well-demarcated, peripheries more common
Rx for vitiligo
sunblock for affected areas, camouflage make-up, topical steroids if early
Features of retinitis pigmentosa
black bone spicule-shaped pigmentation in the peripheral retina, mottling of the retinal pigment epithelium, night, tunnel blindness,
Associations of retinitis pigmentosa
Refsum’s, Usher, abetalipoproteinaemia, Lawrence-Moon-Biedl, Kearns-Sayre, Alport’s
Erythema ab igne features
reticulated, erythematous patches with hyperpigmentation, telangiectasia
Compliations of erythema ab igne
Squamous cell ca
dermatitis herpetiformis features
Itchy vesicular lesions on extensor surfaces.
How to diagnose dermatitis herpetiformis
90% have small bowel biopsy consistent with gluten-sensitive enteropathy
direct immunofluorescence - deposition of IgA in a granular pattern in the upper dermis
Rx for dermatitis herpetiformis
gluten-free diet
dapsone
pityriasis versicolor cause
malessezia furfur infection
features of pityriasis versicolor
Trunk affected, hypopigmentd, pink or brown (versicolor), more noticeable following suntan, scaly, pruritic.
RF for pityriasis versicolor
immunosuppression, malnutrition, Cushing’s.
Rx for pityriasis versicolor
- topical ketoconazole 2. Oral itraconazole + consider alternative dx (skin scrapings)
Pityriasis rosea cause
HHV6 or 7 reactivation
Recentviral infection
Features of pityriasis rosea
Herald patch on trunk followed by erythematous, oval, scaly patches with longitudinal diameters of oval lesions running parallel to line of Langer - fir-tree appearance. Scaling confined to just inside edges.
Rx for pityriasis orsea
self-limiting within 6-12 wks
Hereditary haemorrhagic telangiectasia/Osler’Weber-Rendu syndrome inheritance pattern
Aut dom with age related penetrance
20% spontaneous
Dx for osler-weber-rendu/HHT
2/4 of criteria: epistaxis (spontaneous, recurrent nosebleeds), telangiectases (multiple at characteristic sites - lips, oral cavity, fingers, nose), visceral lesions (GI telangiectasia +/- bleeding, pulmonary, hepatic, cerebral, spinal AVMs), FHx (1st degree relative with HHT)
Acne vulgaris features and severity classification
obstruction of pilosebaceous follicles with keratin plugs resulting in comedones, inflammation, pustules.
Mild: open/closed comedones +/- sparse inflammatory lesions.
Moderate: widespread non-inflammatory lesions + numerous papules/pustules.
Severe: extensive inflammatory lesions, may include nodules, pitting, scarring
Treatment for mild-moderate acne vulgaris
12 wks topical combination (adapalene + benzoyl peroxide, tretinoin + clindamycin, benzoyl peroxide + clindamycin) or topical benzoyl peroxide as monotherapy if contraindications present
Rx for mod-severe acne vulgaris
12 wks topical combination rx +/- oral lymecycline/doxy, or topical azelaic acid + oral lymecycline/doxycycline
Doyxycyline contraindications
Pregnancy/breastfeeding, <12yrs
Alternative for doxycycline in acne vulgaris if pregnant
erythromycin
Minocycline SE
irreversible pigmentation
Max abx course in acne vulgaris
6 months
What is co-prescribed with abx to avoid abx resistance in acne vulgaris?
topical retinoid or benzoyl peroxide
Compl of treatment with abx in acne vulgaris and how to manage this?
Gram negative folliculitis - rx high dose oral trimethoprim
When to refer to dermatology in acne vulgaris?
acne conglobate (rare, severe form in men with extensive inflammatory papules, suppurative modules that may coalesce to form sinuses, and truncal cysts)
Consider if: refractory to 2 courses of Rx or with oral abx, acne with scaring, with persistent pigmentary changes, contributing to significant psych distress/MH disorder
Retinoids SE
teratogenicity, dry skin, eyes, lips/mouth (most common), low mood, raised triglycerides, hair thinning, nose bleeds, intracranial HTN (don’t combine with tetracyclines), photosensitivity
Acne roosacea sx
chronic skin condition. Nose, cheeks, forehead, flushing (1st sx often), telangiectasia. Later becomes persistent erythema with papules. Rhinophyma, blepharitis, sunlight exacerbates.
Rx for acne rosacea
simple measures (daily high-factor sunscreen, camouflage creams), topical brimonidine (alpha agonist) for predominant erythema/flushing sx (reduces redness in 30 mins, peaks at 3-6hrs)
Mild-mod papules/pustules: topical ivermectin, topical metronidazole or azelaic acid for alternative
Moderate-severe papules/pustules: topical ivermectin + oral doxy
Refer if sx not improved post primary care or rhinophyma → laser therapy for prominent telangiectasia
Acanthosis nigricans features
symmetrical, brown, velvety plaques on neck, axilla, groin.
What causes acanthosis nigricans
Due to insulin resistance → hyperinsulinaemia → keratinocyte stimulation + dermal fibroblast proliferation via IGFR1 interaction
Causes (all things to do with weight gain): T2DM, GI Ca, Obesity, PCOS, acromegaly, Cushing’s, hypothyroid, familial, Prader-Willi, drugs (COCP, nicotinic acid)
Acquired icthyosis assx
lymphoma
acquired hypertrichosis lanuginosa assx
GI + lung ca
Dermatomyositis assx
ovarian, lung ca
erythema gyratum repens assx
lung Ca (precedes by 9 months).
Features of erythema gyratum repens
Concentric, erythematous, flat to slightly raised bands with fine white scale in waves located at leading edge of erythema, in wood-grain pattern.
Erythroderma features
> 95% skin involvement with rash.
Causes of erythroderma
Cutaneous T-cell lymphoma (Sezary syndrome), leukaemias eczema, psoriasis, drugs (e.g. gold), idiopathic
What is erythrodermic psoriasis?
progression of chronic disease to exfoliative phase with plaques covering most of body + mild systemic upset. May need admission
Migratory thrombophlebitis assx:
pancreatic ca
necrolytic migratory erythema features
red, blistering lesion that migrate, heal centrally, leave behind areas of hyperpigmentation
necrolytic migratory erythema assx
glucagonoma
Sweet’s syndrome sx
tender, purple plaques - acute febrile neutrophilic dermatosis
Sweet’s syndrome assx:
AML, MDS, haem malignancy
Tylosis assx
oesophageal ca
Lichen planus sx
itchy, papular rash, on palms, soles, genitalia, flexors, polygonal, Wickham’s striae (white lines on surface), Koebner phenomenon possible, oral involvement in 50%, mucosal involvement 70%, thinning of nail plate with longitudinal ridging.
Drug Causes of lichenoid eruptions
gold, quinine, thiazides
Lichen planus rx
potent topical steroids, benzydamine mouthwash/spray for oral lichen planus, oral steroids/immunosuppression for extensive lichen planus
Lichen sclerosus sx
inflammatory condition affecting genitalia, common in elderly females, leads to atrophy of epidermis with white plaques. Sx: white patches, may scar, itchy, dyspareunia/dysuria
Dx of lichen sclerosus
clinical (biopsy if atypical)
Rx for lichen sclerosus
topical steroids, emollients, f/u due to vulval ca risk
livedo reticularis sx
purplish, non-blanching, reticulated rash (obstruction of capillaries → swollen venules).
Scabies organism
sarcoptes scabiei
Causes of livedo reticularis
HIP CASE homocystinuria, idiopathic (most common), PAN, Cryoglobulinaemia, Antiphospholipid syndr, SLE, EDS
Which layer do scabies lay eggs
stratum corneum
Sx of scabies
T4 hypersensitivity 30 days post infection. Sx: Widespread pruritis, linear burrows on sides of fingers, interdigital webs, flexor aspects of wrists. Face and scalp in infants. Excoriations, infections.
Rx for scabies
- Permethrin 5%, 2. malathione 0.5% (apply everywhere, 8-12hrs for permethrin, 24 hrs for malathion, rpt 7 days later). Pruritis persists 4-6 wks post eradication
Crusted scabies: Rx with ivermectin
Sx for molluscum contagiosum
Pinkish/pearly white papules with central umbilication, upto 5mm diameter, clusters.
Rx for molluscum contagiosum
self limiting within 18 months, don’t scratch, explain contagious, no exclusion necessary. Cryotherapy, squeezing, piercing can be tried. Treat eczema if it develops.
Refer if HIV+ve with extensive lesions, eyelid-margin/ocular lesions with red eye, anogenital lesions
Immune related adverse rash rx
topical steroids
severe -systemic steroids
Form of mild topical steroid
Hydrocortisone 0.5-2.5%
Moderate topical steroid forms
Betamethasone valerate 0.025% (Betnovate RD),
Clobetasone butyrate 0.05% (Eumovate)
Potent topical steroid forms
Fluticasone propionate 0.05% (Cutivate), Betamethasone valerate 0.1% (Betnovate)
Very potent topical steroid form
Clobetasol propionate 0.05% (Dermovate)
Finger tip units
1 finger tip unit = 0.5g
hand/fingers 1FTU, a foot 2FTU, front of chest + abdo 7FTU, back + buttocks 7FTU, face + neck 2.5FTU, entire arm + hand 4FTU, entire leg + foot 8FTU
Psoriasis sx
red, scaly patches, nail pitting, onycholysis, arthritis. Worsened by skin trauma/stress, triggered by strep infections, improved by sunlight. Auspitz sign: bleeding when scales scraped off
Genetics for psoriasis
HLA-B13, B17, Cw6. 70% concordance in identical twins
Triggers for psoriasis
NABILA NSAIDS, anti-malarials (chloroquine, hydroxychloroquine), beta blockers, infliximab, lithium, ACE inhibitors + trauma, withdrawal of steroids
Pathophysiology of psoriasis
Abnormal T cell activity → keratinocyte proliferation. Th17, IL17 influence.
Types of psoriasis
plaque
flexural
guttate
pustular
Plaque psoriasis sx:
well demarcated red, scaly patches on extensor surfaces, sacrum, scalp
Scalp psoriasis rx
topical steroids OD 4wks. If no improvement after 4wks, ue different steroid and/or topical agent
Flexural psoriasis rx
mild/moderate topical steroids OD/BD max 2 weeks
Guttate psoriasis sx
transient, children and adolescents, triggered by strep infections (2-4wks before), multiple red/pink, teardrop patches/plaques on trunk + limbs. Onset over days.
Guttate psoriasis rx
Most resolve within 2-3 months, topical agents like in psoriasis, UVB phototherapy also possible. Consider tonsillectomy if recurrent
Pustular psoriasis sx
on palms and soles (e.g. palmoplantar pustulosis - fluid-filled pustules/blisters on hands and feet)
Chronic psoriasis rx
regular emollients. 1. Potent topical steroid OM + vit D analogue OE for 4 wks. 2. After 8 wks, vit D analogue BD. 3. After 8-12 wks, steroids BD for 4 wks or coal tar preparation OD/BD
Phototherapy: narrowband ultraviolet B light 3x/wk, photochemotherapy PUVA (psoralen + ultraviolet A light). SE: skin ageing, squamous cell ca
Systemic: methotrexate, ciclosporin, systemic retinoids, infliximab, etanercept, adalimumab, ustekinumab (IL12, IL23, early trials)
Complications of psoriasis
psoriatic arthropathy (10%), metabolic syndrome, CVS disease, VTE, psychological distress
How do vit d analogues act in chronic psoriasis
by reducing cell division, differentiation. Can be used long-term, does not reduce erythema but reduces scale, thickness of plaques.
Contraindication for vit d analogues
pregnancy
Cause of seborrhoeic dermatitis
malassezia furfur
Sx for seborrhoeic dermatitis
eczematous lesions on scalp, periorbitally, auricular, nasolabial folds. Otitis externa, blepharitis.
Assx for seborrhoeic dermatitis
HIV
PD
Rx for seborrhoeic dermatitis
scalp - ketoconazole, zinc pyrithione, neutrogena, selenium sulphide, topical steroids.
face/body - topical ketoconazole, steroids for short periods
Keratoacanthoma sx
rapidly growing, benign epithelial tumour, initially appear as red dome-shaped papule, develops into a volcano-like crater filled with keratinatous material. Reach max size in wks-months then regress within 3 months.
Rx for keratoacanthoma
excise and exclude SCC, prevent scarring
Actinic keratoses sx
premalignant lesions on sun-exposed areas (face, scalp, arms). Red/pink/brown/neutral colour, small, crusty/scaly lesions.
Actinic keratoses rx
avoid risk, fluorouracil cream (2-3 wk course, skin will become red, inflamed so can give topical hydrocortisone with it), topical diclofenac (for mild), topical imiquimod, cryotherapy, curettage/cautery
Forms of malignant melanomas
Superficial spreading
Nodular
Lentigo maligna
acral lentiginous
Dx for malignant melanoma
Major criteria: change in size, shape, colour
Minor criteria: diameter>7mm, inflammation, oozing/bleeding, altered sensation.
Commonest malignant melanoma
superficial spreading
Superficial spreading melanoma sx
70% (commonest). Arms, legs, back, chest, young people
Nodular melanoma sx
2nd commonest. On sun-exposed skin, middle-aged people, red/black lump which may bleed/ooze. Most aggressive (tends to grow rapidly, downwards into deeper layers of skin, increasing thickness faster than in diameter)
Lentigo maligna sx
chronically sun-exposed skin, older people
acral lentiginous melanoma sx
rare. Nails, palms, soles, in darker skin. Subungual pigmentation (hutchinson’s sign)
Rx for melanoma (guided by what)
excision biopsy by Breslow thickness: 0-1mm: 1cm, 1-2mm: 1-2cm, 2-4mm: 2-3cm, >4mm: 3cm. Any melanoma thicker than 1mm requires sentinel node biopsy
Squamous cell carcinoma RFs
sunlight, psoralen UVA therapy, actinic keratoses, Bowen’s disease, immunosuppression (post-renal tp, HIV), smoking, long-standing ulcers (Marjolin), xeroderma pigmentosum, oculocutaneous albinism.
Sx for Squamous cell ca
rapidly expanding painless, ulcerated nodules on sun-exposed sites such as head, neck, dorsum of hands and arms, cauliflower-like appearance, bleeding areas.
Rx for squamous cell ca
surgical excision with 4mm margins if diameter<20mm. 6mm if >20mm. Mohs micrographic surgery for high risk/cosmetically important sites.
Good prognosis factors for Squamous cell ca
well differentiated, <20mm diameter, <2mm depth, no assx diseases
poor prognosis factors for squamous cell ca
poorly differentiated, >20mm diameter, >4mm depth, immunosuppression
Basal cell ca sx
Rodent ulcers, slow growing, local invasion, rare mets. Nodular most common. Sun-exposed sites, pearly flesh-coloured papule + telangiectasia, may ulcerate leaving central crater.
Rx for BCC
routine referral, surgical removal/curettage/cryotherapy/topical cream (imiquimod, fluorouracil)/radiotherapy
Systemic mastocytosis sx
neoplastic mast cell proliferation. Sx: urticaria pigmentosa, Darier’s sign (wheal on rubbing), flushing, abdo pain, monocytosis on blood film
Dx for systemic astocytosis
high serum tryptase, urinary histamine
Systemic mastocytosis forms
Indolent
Smouldering
Aggressive
Features of smouldering systemic mastocytosis
2 or more B findings: bone marrow>30% mast cells +/- tryptase >200ng/ml +/- KITD816V mutation with variant allele frequency (VAF) of >10%, signs of dysplasia/myeloproliferation without frank haem malign + normal FBC, hepatomegaly without liver dysfunction +/- splenomegaly without hypersplenism
Features of aggressive systemic mastocytosis
1 or more C findings (cytoreduction-requiring/organ dysfunction): one or more cytopenias (Hb<100, pltl<100, neutrophils<1.0, hepatomegaly + liver dysfunction, osteolytic lesions/#, splenomegaly with hypersplenism, malabsorption with weight loss due to GI infiltration
Zinc deficiency sx
acrodermatitis (red, crusted lesions acrally, peri-orificial, perianal), alopecia, short stature, hypogonadism, hepatosplenomegaly, geophagia (ingesting clay/soil), cognitive impairment.
Acrodermatitis enteropathica
aut recessive partial defect in intestinal zinc absorption
Alopecia forms
scarring, non-scarring
Scarring alopecia forms
(destruction of hair follicle): trauma, burns, radiotherapy, lichen planus, discoid lupus, tinea capitis.
Non-scarring alopecia forms
(preservation of hair follicle): male-pattern baldness, drugs (cytotoxics, carbimazole, heparin, contraceptives, colchicine), iron, zinc deficiency, alopecia areata, telogen effluvium (post-stressful period), trichotillomania
Alopecia areata sx
autoimmune, localised, well demarcated patches of hair loss, with small, broken ‘exclamation mark’ hairs.
Rx for alopecia areata
Will regrow in 50% in 1yr, 80-90% eventually. Otherwise, topical/intralesional steroids, topical minoxidil, phototherapy, dithranol, contact immunotherapy, wigs
Pompholyx sx:
eczema type (dishidrotic), affecting hands (cheiropompholyx), feet (pedopompholyx).
Sx: small blisters on palms, soles, intensely itchy, burning, dry, cracking skin.
Triggers of pompholyx
humidity, high temperatures
Rx for pompholyx
cool compress, emollients, topical steroids
Keloid scar rfs
dark skin, young adults, sternum, shoulder, neck, face, extensor surfaces, trunk. (less likely if incisions made along relaxed skin tension lines)
Sx for keloid scars
from connective tissue of scar, extends beyond dimensions of original wound
Keloid scars rx
intra-lesional steroids (eg triamcinolone)
Eczema herpeticum causes
HSV1/2
coxsackievirus A16
Vaccinia
eczema herpeticum sx
Commonly seen in children with atopic eczema. Sx: rapidly progressing painful rash, monomorphic, punched-out erosions (circular, depressed, ulcerated lesions), 1-3mm diameter.
Rx for eczema herpeticum
Admission + IV aciclovir
Dermatitis artefacta RF
self-induced,
adolescent females
personality disorder, dissociative disorders, eating disorders (33% increased in bulimia, anorexia).
Dermatitis artefacta sx
linear/geometric lesions, well-demarcated, appear suddenly, face, dorsum of hands, la belle indifference.
Antihistamine forms
sedating (also have antimuscarinic properties): chlorpheniramine.
Non-sedating: loratidine, cetirizine
Pellagra dermatitis sx
brown scaly rash on sun-exposed sites - Casal’s necklace if on neck
Venous ulcers location
typically above medial malleolus
Venous ulcers ix:
ABPI in non-healing ulcers (assess for poor arterial flow which impairs healing) (normal 0.9-1.2, arterial disease<0.9. ?calcification (eg in diabetics) >1.3).
Rx for venous ulcers
compression bandaging (4 layers), oral pentoxifylline (peripheral vasodilator), flavinoids
Atopic eruption of pregnancy
commonest prengancy skin disorder, eczematous, itchy rash, resolves
Polymorphic eruption of pregnancy
pruritic, last trimester, lesions first in abdominal striae, spares umbilicus
Rx: depends on severity - emollients, mild potency topical steroids, oral steroids
Pemphigoid gestationis
pruritic blistering lesions, develop peri-umbilically and spreads to trunk, back, buttocks, arms, 2nd/3rd trimester.
Rx: oral steroids
Melasma
common in early pregnancy, resolves, symmetrical brown-pigmented patch across cheeks, forehead, nose, upper lip
Fungal nail infections causes
dermatophytes (tricophyton rubrum) 90%, yeasts (5-10%), non-dermatophyte moulds.
RF for fungal nail infections
age, DM, psoriasis, repeated nail trauma.
Fungal nail infections sx
unsightly nails, thickened, rough, opaque nails.
Ix for fungal nail infections
nail clippings +/- scrapings.
Rx for fungal nail infections
(if dermatophyte or candida confirmed)
Limited involvement (<50% nail affected, <2 nails affected, more superficial white onychomycosis): topical amorolfine 5% lacquer (6 months fingernails, 3-6 months toenails)
Oral itraconazole for more extensive candida
What is Yellow nail syndrome and its assx
slowing of nail growth leading to thickened, discoloured nails.
Assx: congenital lympoedema, pleural effusions, bronchiectasis, chronic sinus infections
What is Koebner’s phenomenon and assx
skin lesions at site of injury.
Assx: psoriasis, vitiligo, warts, lichen planus, lichen sclerosus, molluscum contagiosum
Tinea forms
capitis
corporis
pedis
Tinea capitis sx
scalp ringworm. Scarring alopecia in children. Kerion may form if untreated - raised, pustular, spongy/boggy mass
Tinea capitis organisms
Tricophyton tonsurans commonest. Microsporum canis from cats/dogs
Dx for tinea capitis
scalp scrapings
Wood’s lamp - microsporum canis shows green fluorescence
Rx for tinea capitis
oral terbinafine for tricophyton tonsurans, griseofulvin for microsporum. Topical ketoconazole shampoo for 2wks to reduce transmission
Tinea corporis organisms
Tricophyton rubrum, verrucosum.
Sx for tinea corporis
well-defined annular, erythematous lesion with pustules, papules.
Rx for tinea corporis
oral fluconazole
Tinea pedis sx
athlete’s foot. Itchy, peeling skin between toes.
Wood’s light staining for PCT
pink
Wood’s light staining for tinea capitis microsporum canis
green
wood’s light staining for malassezia furfur
green
wood’s light staining for erythrasma
red (coral)
Hyperhidrosis rx
topical aluminium chloride (SE: skin irritation), iontophoresis (useful for palmar, plantar, axillary hyperhidrosis), botulinum toxin (for axillary sx), surgery (eg endoscopic transthoracic sympathectomy - compensatory sweating risk)
