Acute and Emergency Dermatology Flashcards

Question

What is Erythema Multiforme?

Answer 1

-Usually a mild illness affecting the distal skin surfaces of young people, possibly with mild mucosal involvement. -The classical clinical appearance is the ‘target’ lesion. -Virtually all cases of erythema multiforme are an immunological response to an earlier infection (such as herpes simplex).

Answer 2

-Target lesion: annular lesion with a red or dusky cyanotic centre, and a bright erythematous outer ring, separated by a slightly paler zone. There are therefore 3 colours to the target. -Haemorrhage or blistering may occur in the central lesion. -The lesion is initially macular, but then may become raised. -The rash is most common on the extremities: acral (hand and soles), face, elbows, knees. -Erythema multiforme is most common in young people (under the age of 40) with males suffering more commonly than females.

Answer 3

-Infections, commonly herpes simplex or mycoplasma. -Other infections may cause it too -Very rarely drugs might precipitate EM (emphasis on the word ‘rare’) -In HSV caused EM you find expression of HSV DNA within the skin lesions (although you cannot cultivate the virus from the skin lesions)

Answer 4

-18 year-old male who develops herpes simplex (often recurrent) and then a week to two weeks later, develops the characteristic target lesions of EM on his palms which then spread to other body sites and the mucosae. The initially macular lesions appear over the course of a day, and are fully developed at three days with bullae and haemorrhage in some cases. They subside over a few weeks, without any scarring of the skin

Answer 5

-EM minor and EM major -In the former, mucosal disease is mild or absent, whereas in EM major it is more severe. -Fever and joint pains are a feature of EM major but are absent in EM minor

Answer 6

-Diagnosis is usually suspected clinically but biopsy confirmation is sometimes warranted. -The classic features are of widespread epidermal cell death (keratinocyte death) with some dermal inflammation. -You need to interpret the pathology with the clinical appearance, as the histology is not pathognomonic

Answer 7

-If patients develop repeated episodes, it is almost certainly due to recurrent herpes simplex (even if herpes simplex is not clinically obvious) =chronic antiviral treatment with aciclovir or a similar antiviral agent should be considered. -In the acute phase, no treatment beyond basic skin care with antiseptics is usually necessary. -If EM is markedly symptomatic some people use topical steroids. -Some clinical experts in this group of disorders have used systemic steroids for severe EM although good evidence for efficacy is lacking. -If mucosal involvement is severe, IV fluids might be needed (uncommon). -Eye involvement with or without symptoms warrants an ophthalmology consult, because of the potential for late scarring

Answer 8

-Catastrophic response to a drug, that picks out some people and not others on the basis of variation in drug metabolism and immunological reaction (peak risk from a drug is between 7 and 28 days after commencement, risk greater in immunosuppressed) -It results in large sheets of epidermal / keratinocyte cell death, resembling a widespread burn, with mucosal involvement. It has a mortality of up to 50% in some contexts -Most common in the elderly, but can occur (very rarely) in children, and is a potentially fatal skin and mucosal adverse drug reaction -The main cause of death is infection and the hypercatabolic state

Answer 9

-Sudden onset of diffuse erythema with sheets of skin undergoing necrosis (extreme pain) -Wrinkling or blisters within those sheets may be seen. -The epidermis lifts off the basement membrane due to widespread keratinocyte cell death. Rubbing normal apparent skin will cause the epidermis to come away — TEN is Nikolsky positive. -Pyrexia, malaise, dysuria and sore eyes, may precede the onset of the rash. -Macular deep red/blue areas with some similarities to target lesions may be seen, but classical target lesions are not seen. -Whereas EM is acral and peripheral, TEN is often worst on the trunk, although any area can be affected.

Answer 10

Full thickness epidermal death due to Fas mediated cell apoptosis

Answer 11

-Stop relevant drugs ASAP! =All drugs except absolutely essential drugs should be stopped (drugs have a slow half life or the immunological reaction that underpins this disorder may be to drug metabolites that may have a prolonged half-life) =allopurinol, carbamazepine, sulphonamides are high risk/ AAA (antibiotics such as beta lactams, anti-epileptics, allopurinol) -General: = HDU / ITU =monitor fluid balance, ensure adequate analgesia and to advise. =A controlled pressure thermoregulated bed and aluminium survival sheet =Skilled dermatological nursing =Ophthalmological input is required to assess ocular involvement -Specific =IV immunoglobulin (IVIG) =anti-TNF drugs (infliximab or thalidomide), as has ciclosporin in the past

Answer 12

Clinical scoring system called the SCORTEN, which provides some prognostic information, and is based on age, extent of rash, heart rate, glucose, bicarbonate level etc. TEN has an overall mortality of ~40%, with a SCORTEN score of over 5 predicting death in 90% of cases

Answer 13

-Milder variant of TEN with a body area involvement of <10%, but with mucosal involvement. -The pathophysiology and cause of SJS is similar to that of TEN, but morbidity and mortality is lower, with a mortality rate for SJS of <5%

Answer 14

-Result of a circulating toxin produced by particular subtypes of staphylococci. -The toxin is a serum protease that cleaves desmoglein 1 (Dsg1) (a key component of the desmosome high up in the epidermis and this target antigen is the same as in pemphigus foliaceous). - In SSSS the toxin is circulating, whereas in bullous (staphylococcal) impetigo the toxin is localised to (a) particular area(s) of the skin

Answer 15

-Dsg1 is not a component of the mucosal desmosomes so mucosae are not affected (contrast with pemphigus vulgaris, and TEN) -Children under 5/ immunosuppressed or have renal failure (the toxin is cleared by the kidney) -The site of the staph infection is not usually the skin, and skin swabs will usually be negative (contrast with impetigo) -In children, common sites of infection are the nasopharynx or the conjunctivae -Onset is with a scarlet fever like rash, often around the mouth and nappy area, with perioral crusting and furrowing. -The erythema first appears on the face, with or without oedema, and then generalises particularly to intertriginous sites -The child is pyrexial but often looks reasonably well (at least initially) -There is intense pain, with separation of the skin in sheets on a red base -Over 48 hours widespread flaccid blisters develop. The Nikolsky sign may be positive. The child looks as though it has been scalded (hence the clinical epithet, ‘scalded skin’).

Answer 16

-Clinical suspicion. The child may not be very ill (initially). -A superficial biopsy will support the diagnosis, and differentiate SSSS from TEN -Culture swabs from the throat, and eyes. =negative

Answer 17

-IV anti-staphylococcal drugs (flucloxacillin, vancomycin, or as advised by microbiology). -Supportive care is important as is barrier nursing. -Mortality with treatment is very low. -SSSS rarely occurs in adults, but can occur in the chronically immunosuppressed adults and in sick patients on ITU

Answer 18

-Urticarial rash with or without angioedema (IgE mediated reaction causing degranulation of mast cells) =allergies to penicillins =Anaphylaxis is rare but possible - especially after iv injections

Answer 19

-Classic and most common cutaneous reaction to a drug. -Exanthematous reaction that mimics the rash seen in a variety of infections such as measles, rubella, roseola, erythema infectiosum, glandular fever etc.) -Erythematous, in places macular and in others papular, usually with minimal scale, and is sometimes itchy. -The rash typically starts somewhere between 4 days and 21 days after taking the medication, but sooner if the medication has been taken previously. T -he rash seen with penicillin and glandular fever normally occurs quicker (within days). -The frequent clinical problem is distinguishing between drugs as the cause of the rash, and a rash directly caused by an infectious agent (e.g. virus). -no severe systemic involvement (as in, not DRESS) - no blisters - no mucosal involvement - no target lesions of erythema multiforme - no necrolysis / widespread epidermal necrosis (TEN) -If there is a candidate drug, and it is safe to do so, stop the drug. If the drug cannot be safely stopped (usually based on discussion with other medical staff), wait and see, as the cutaneous disease alone will not kill the patient. (This assumes all the ‘negatives’ listed above apply).

Answer 20

-Drug Reaction with Eosinophilia and Systemic Symptoms. -Widespread rash (possibly erythrodermic), that may be eczematous with or without facial oedema. -There may be purpura especially on the lower legs. -The rash normally occurs over 2 weeks after the drug was started, and therefore the rash may appear after the drug has been stopped. -Other clinical features include:- lymphadenopathy- pyrexia- hepatitis- nephritis. -Well known precipitants include carbamazepine, phenytoin, dapsone and allopurinol. -Much of there action seems to be an immunological response to reactivation of latent viral infections, such as herpesvirus 6 and cytomegalovirus virus infection. -The reaction may persist for several weeks or more, and there is an overall mortality rate of 10%, usually from hepatitis. -Supportive care is important, as is stopping any causative drugs as early as possible. -Systemic steroids are frequently used

Answer 21

-Red, round, plaques with erythema and even blistering, that resolve leaving marked hyperpigmentation. -Frequently the original inflammation has not been noticed, it’s only the resulting pigmentation that causes the patient to consult. -They are associated with a variety of drugs, including NSAIDs and penicillins and occur on a particular single body site, or multiple body sites, and reoccur at the same site if the drug is used on a further occasion (hence, the ‘fixed’ epithet). -They are most common on the genitalia, lips, or acral skin. -Each time the drug is taken, the physical signs return — in the same site (although further new sites may develop)

Answer 22

-Characterised by fever, and a widespread pustular rash that resembles pustular psoriasis. -Systemic steroids are said to help. -Biopsy, skin folds

Answer 23

-Widespread erythema, or papulo squamous rash. -Particular diagnostic break off points such as 90% involvement are rather unrealistic, as by and large, people are not very good at estimating body surface area accurately. -Essentially we mean most / virtually all of the skin

Answer 24

1. Psoriasis 2. Atopic dermatitis or other forms of eczema 3. Drug reactions 4. Cutaneous T-cell lymphoma

Answer 25

-Patients require supportive care, as their skin will feel uncomfortable and itchy. -They can become seriously ill, particularly if there are co-morbidities. -The main issues to consider: =Fluid loss from the skin is greatly increased, and thermoregulation is markedly impaired. Sweat gland duct occlusion (blockage) may occur, leading to an inability to lose heat from sweating, leading to hyperthermia. Conversely, the large volume of blood circulating through the skin may result in hypothermia. These patients are therefore at risk of both hypothermia and hyperthermia. The former is more likely. =The hypothermia is said to be concealed because the patients look as though they are hot (high skin blood flow, with warm peripheries), but in reality the core temperature is reduced. =Thermoregulatory abnormalities may precipitate rigours, shivers and significant malaise. -Admission and skilled nursing support. -Emollients, topical corticosteroids, systemic corticosteroids, ciclosporin, retinoids or watchful waiting. -Such patients feel sick, and their skin is ‘uncomfortable’

Answer 26

-Characterised by recurrent flares of widespread sterile pustules with erythematous, painful skin. -GPP can be associated with systemic inflammation including fevers and/or hepatic, gastrointestinal, musculoskeletal, renal, or pulmonary involvement. Management: =Emollients, IV fluids and electrolytes, analgesia =Topical: calcipotriol/ tacrolimus/ steroids =Ciclosporin/ methotrexate/ retinoids/ mycophenolate =Biologics

Acute and Emergency Dermatology Flashcards

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