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Livedo reticularis questions and answers already graded A+(with pictures).
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Livedo reticularis questions and answers already graded A+(with pictures).
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Livedo reticularis questionsand answers already graded
A+(with pictures)
Purplish, non blanching, reticulated rash.
Causes - Idiopathic, SLE, polyarterisis nodosa, EDS, anti-
phospholipid syndrome, cryoglobulinaemia, homocystinuria.
MRSA
If impetigo treated with fusidic acid but no improvement - consider
MRSA and treat with mupirocin
Erythema ab igne
Caused by over exposure to infrared radiation, risk of SCC
Keloid scar treatment
Early keloids can be treated with intra-lesional steroids like
triamcinolone
Skin conditions and cancer associations
Glucagonoma - necrolytic migratory erythema
Pyoderma gangrenosum - myeloproliferative disorder
sweets syndrome - haematological malignany
Acanthosis nigricans - gastric cancer
acquired ichthyosis - lymphoma
acquired hypertrichosis - GI and lung cancer
Dermatomyositis - ovarian and lung
Erythema gyratum - lung
Erythroderma - lymphoma
Migratory thrombophlebitis - pancreatic
Pyoderma gangrenosum - myeloproliferative disorder
SJS risk factor
HLA B1502 - carbamazepine induced SJS in Han chinese
,Koebner phenomenon
Skin lesions appear at site of injury - Warts And ALL - warts,
autoimmune, AIDS, lichen planus, lichen sclerosis. Also psoriasis,
vitiligo, warts, molluscum contagiousm.
Psoriasis - exacerbating factors
Trauma, alcohol, beta blockers, lithium, antimalarials, NSAIDs, ACE
inhibitors, withdrawal of systemic steroids, penicillin, tetracyclines
Topical steroids
Mild - hydrocortisone 0.5-2.5%
Moderate - betamethasone valerate 0.025% (betnovate RD),
clobetasone butyrate 0.05% (eumovate)
Potent - fluticasone propionate 0.05% (cutivate), betamethasone
valerate 0.1% (betnovate)
Very potent - clobetasol propionate 0.05%
Erythema Multiforme
Hypersensitivity reaction. Features are target lesions, initially on
back of hands/feet before spreading to torso. Upper limbs more
than lower limbs. Pruritis occasionally seen and usually mild.
Causes -
Viral - HSV (most common), Orf (skin disease of sheep and goats
caused by parapox virus.)
Idiopathic,
Bacteria - mycoplasma, streptococcus
Drugs - penicillin, sulphonamides, carbamazepine, allopurinol,
NSAIDs, oral contraceptive pill, nevirapine.
SLE
Sarcoidosis
Malignancy
Erythema multiforme major - most severe form, with mucosal
involvement.
Rosacea
flushing, telangiectasia, then persistent erythema and papules and
pustules, rhinophyma, blepharitis, sunlight exacerbates. Treatment
- simple measures like sunscreen.
Predominant erythema - topical brimonidine gel - alpha adrenergic
agonist, PRN basis, reduces redness within 30 mins, peaks 3-6
hours, then redness returns to baseline.
,Mild to moderate papules/pustules - topical ivermectin first line ,
alternative topical metronidazole or azelaic acid. Moderate- Severe -
oral tetracycline (doxy) and topical ivermectin.
Refer if symptoms not improved in primary care with optimal
treatment, laser may be appropriate for patients with prominent
telangiectasia, rhinophyma
Erythrasma
Flat, scaly, pink/brown rash in groin or axilla. Overgrowth of
diptheria cornebacterium. Topical miconazole or antibacterial, oral
erythromycin if more extensive.
Systemic mastocytosis
Neoplastic proliferation of mast cells , dariers sign - rubbing
produes wheal. Also flushing, abdominal pain, monocytosis on blood
film. Diagnosis urinary histamine and raised serum tryptase levels.
Pityriasis versicolor
Patches of hypopigmentation more common after sun exposure,
fungal infection called malassezia. Ketoconazole shampoo to treat,
if doesn't work send scrapings to rule out other diagnosis, + oral
itraconazole. Scale common, mild pruritis.
Can occur in healthy individuals, associated with
immunosuppression, malnutrition and cushings
Yellow-green fluorescence under woods lamp.
Bullous pemphigoid vs Pemphigus vulgaris
Pemphigoid - Ab against hemidesmosomal proteins BP180 and
BP230. Immunofluorescence shows IgG and C3 at dermoepidermal
junction
Affects elderly patients, itchy tense blisters around flexures.
Blisters usually heal without scarring.
Causes include furosemide, pencilliamine, captopril and penicillin
derivatives.
Typically spares mucosal surfaces (unlike pemphigus vulgaris)
Refer to Dermatology for skin biopsy. Oral steroids the treatment,
sometimes topical steroids, immunosuppressants and antibiotics
, used.
Pemphigus vulgaris - antibodies against desmoglein 3, more
common in Ashkenazi jews.
Mucosal ulceration common, oral involvement in 50-70% of patients.
Skin blistering, easily ruptured vesicles and bullae. Painful but not
itchy. Nikolsys describes spread of bullae following horizontal
pressure to the skin. Acantholysis on biopsy. Steroids first line,
immunosuppressants.
Erythema nodosum causes
Inflammation of subcut fat, tender nodular lesions typically on skins
but also forarms, thighs. Usueal resolve in 6 weeks without scarring.
Causes:
Infection - strep (most commonly strep pyogenes, 25-45% of all
cases of erythema nodosum due to strep throat) , TB, brucellosis
Sarcoidosis, IBD, behcets
Malignancy/lymphoma
penicillin, sulphonamides, COCP
Pregnancy
Porphyria
photosensitive rash with blistering and skin fragility on face and
dorsal aspect of hands, hypertrichosis, hyperpigmentation.
Yellow nail syndrome
Congenital lymphedema, pleural effusions, bronchiectasis, chronic
sinus infections
Eczema herpeticum
HSV 1 or 2, monomorphic punched out lesions, can be life
threatneing, IV aciclovir. Can also more rarely be caused by
coxsackie virus.
Scabies
Caused by mite sarcoptes scabiei. Intense itching due to delayed
type IV hypersensitivity reaction to mites/eggs 30 days after initial
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