Drug Eruptions Flashcards
What is Stevens-Johnson syndrome?
severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction.
Features of SJS?
rash is typically maculopapular with target lesions being characteristic. May develop into vesicles or bullae
mucosal involvement
systemic symptoms: fever, arthralgia
Causes of SJS?
penicillin sulphonamides lamotrigine, carbamazepine, phenytoin allopurinol NSAIDs oral contraceptive pill
Mx SJS?
hospital admission is required for supportive treatment
What is Toxic epidermal necrolysis?
Toxic epidermal necrolysis (TEN) is a potentially life-threatening skin disorder that is most commonly seen secondary to a drug reaction. In this condition, the skin develops a scalded appearance over an extensive area.
What is a +ve Niklosky’s sign?
epidermis separates with mild lateral pressure
Features of TEN
systemically unwell e.g. pyrexia, tachycardic
positive Nikolsky’s sign
Drugs known to induce TEN
phenytoin sulphonamides allopurinol penicillins carbamazepine NSAIDs
Mx TEN?
stop precipitating factor
supportive care
often in an intensive care unit
volume loss and electrolyte derangement are potential complications
intravenous immunoglobulin has been shown to be effective and is now commonly used first-line
other treatment options include: immunosuppressive agents (ciclosporin and cyclophosphamide), plasmapheresis
What is acanthosis nigricans?
Describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.
Drugs causes of acanthosis nigricans?
combined oral contraceptive pill
nicotinic acid
causes of acanthosis nigricans?
type 2 diabetes mellitus gastrointestinal cancer obesity polycystic ovarian syndrome acromegaly Cushing's disease hypothyroidism familial Prader-Willi syndrome
pathophysiology of acanthosis nigricans?
insulin resistance → hyperinsulinemia → stimulation of keratinocytes and dermal fibroblast proliferation via interaction with insulin-like growth factor receptor-1 (IGFR1)
Erythema ab igne is a skin disorder caused by
over exposure to infrared radiation.
Erythema ab igne, Characteristic features include
reticulated, erythematous patches with hyperpigmentation and telangiectasia.
Erythema ab igne, typical history
an elderly women who always sits next to an open fire.
Erythema ab igne is self limiting
false
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
What is erythema multiforme?
Erythema multiforme is a hypersensitivity reaction which is most commonly triggered by infections
It may be divided into minor and major forms.
Features of erythema multiforme
target lesions
initially seen on the back of the hands / feet before spreading to the torso
upper limbs are more commonly affected than the lower limbs
pruritus is occasionally seen and is usually mild
Causes of erythema multiforme
viruses idiopathic bacteria drugs connective tissue disease e.g. Systemic lupus erythematosus sarcoidosis malignancy
Viruses & bacteria that cause erythema multiforme
viruses: herpes simplex virus (the most common cause), Orf is a skin disease of sheep and goats caused by a parapox virus
bacteria: Mycoplasma, Streptococcus
Drugs that cause erythema multiforme?
penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
The more severe form, erythema multiforme major is associated with
mucosal involvement.
Describe Erythema nodosum
inflammation of subcutaneous fat
typically causes tender, erythematous, nodular lesions
usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs)
lesions heal without scarring
Erythema nodosum resolves within
usually resolves within 6 weeks
Causes Erythema nodosum
infection systemic disease:sarcoidosis, inflammatory bowel disease, Behcet's malignancy/lymphoma drugs pregnancy
Erythema nodosum drugs?
penicillins
sulphonamides
combined oral contraceptive pill
Erythema nodosum infection?
streptococci
tuberculosis
brucellosis
Causes of erythroderma
eczema psoriasis drugs e.g. gold lymphomas, leukaemias idiopathic
What is erythrodermia?
Erythroderma is a term used when more than 95% of the skin is involved in a rash of any kind.
What is Erythrodermic psoriasis?
may result from progression of chronic disease to an exfoliative phase with plaques covering most of the body. Associated with mild systemic upset
more serious form is an acute deterioration.
Erythrodermic psoriasis triggered by?
may be triggered by a variety of factors such as withdrawal of systemic steroids.
mx Erythrodermic psoriasis
Patients need to be admitted to hospital for management
What is Hirsuitism and hypertrichosis?
Hirsutism is often used to describe androgen-dependent hair growth in women, with hypertrichosis being used for androgen-independent hair growth
most common causes of hirsutism
Polycystic ovarian syndrome
Causes of PCOS?
Cushing's syndrome congenital adrenal hyperplasia androgen therapy obesity: thought to be due to insulin resistance adrenal tumour androgen secreting ovarian tumour drugs
Drugs that cause PCOS
phenytoin, corticosteroids
Assessment of hirsutism
Ferriman-Gallwey scoring system: 9 body areas are assigned a score of 0 - 4, a score > 15 is considered to indicate moderate or severe hirsutism
Management of hirsutism
advise weight loss if overweight
cosmetic techniques such as waxing/bleaching - not available on the NHS
consider using combined oral contraceptive pills such as co-cyprindiol (Dianette) or ethinylestradiol and drospirenone (Yasmin). Co-cyprindiol should not be used long-term due to the increased risk of venous thromboembolism
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
Causes of hypertrichosis
drugs: minoxidil, ciclosporin, diazoxide
congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
porphyria cutanea tarda
anorexia nervosa
What is Pellagra?
Pellagra is a caused by nicotinic acid (niacin) deficiency. The classical features are the 3 D’s - dermatitis, diarrhoea and dementia.
Pellagra may occur as a consequence of isoniazid therapy (isoniazid inhibits the conversion of tryptophan to niacin) and it is more common in alcoholic
Features of Pellagra?
dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck)
diarrhoea
dementia, depression
death if not treated
What are Spider naevi
Spider naevi (also called spider angiomas) describe a central red papule with surrounding capillaries. The lesions blanch upon pressure. Spider naevi are almost always found on the upper part of the body.
Spider naevi can be differentiated from telangiectasia by pressing on them and watching them fill. Spider naevi fill from the centre, telangiectasia from the edge .
Around 10-15% of people will have one or more spider naevi
true
Spider naevi more common in childhood
false
Causes of spider naevi
liver disease
pregnancy
combined oral contraceptive pill
most important causes of pruritus?
Liver disease Iron deficiency anaemia Polycythaemia Chronic kidney disease Lymphoma
Other causes: hyper- and hypothyroidism diabetes pregnancy 'senile' pruritus urticaria skin disorders: eczema, scabies, psoriasis, pityriasis rosea
Describe pruritus in Liver disease?
History of alcohol excess
Stigmata of chronic liver disease: spider naevi, bruising, palmar erythema, gynaecomastia etc
Evidence of decompensation: ascites, jaundice, encephalopathy
Describe pruritus in Iron deficiency anaemia?
Pallor
Other signs: koilonychia, atrophic glossitis, post-cricoid webs, angular stomatitis
Describe pruritus in Polycythaemia?
‘Ruddy complexion’
Gout
Peptic ulcer disease
Describe pruritus in Lymphoma?
Night sweats
Lymphadenopathy
Splenomegaly, hepatomegaly
Fatigue
Describe Porphyria cutanea tarda
Porphyria cutanea tarda is the most common hepatic porphyria.
Causes Porphyria cutanea tarda?
It is due to an inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, hepatitis C, oestrogen.
Features of Porphyria cutanea tarda?
classically presents with photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
hypertrichosis
hyperpigmentation
Investigations of Porphyria cutanea tarda?
urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
serum iron ferritin level is used to guide therapy
mx Porphyria cutanea tarda?
chloroquine
venesection
preferred if iron ferritin is above 600 ng/ml
What is lichen planus?
Lichen planus is a skin disorder of unknown aetiology, most probably being immune-mediated.
Features of lichen planus?
itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
What eponymous features will you see in Lichen Planus?
‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
Lichenoid drug eruptions - causes:
gold
quinine
thiazides
Mx lichen planus?
potent topical steroids are the mainstay of treatment
benzydamine mouthwash or spray is recommended for oral lichen planus
extensive lichen planus may require oral steroids or immunosuppression
