Target or target-like lesions are seen in all of the following conditions EXCEPT:
Answer: D: Typical target lesions can be seen in erythema multiforme (EM). In addition, erythematous macules and papules, vesiculaobullous lesions and urticaria may occur in this condition. In SJS similar lesions are seen but the target lesions can be atypical. In TEN vesicles and bullae are the main lesions and there is associated painful and tender erythroderma and exfoliation. Furthermore, flat atypical targets may be seen in TEN. Pyoderma gangrenosum is a dermatosis with dense dermal infiltrate of neutrophils (a neutrophilic dermatosis). It is often associated with inflammatory bowel disease, rheumatoid arthritis and leukaemia. It results in severe painful ulceration frequently in the lower limbs and it is not associated with target lesions.
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Which ONE of the following statements is TRUE regarding SJS and toxic epidermal necrolysis?
Answer: A: SJS and TEN are now considered two variants of the same disease process and they are different to EM. Although very rare, these conditions are caused almost exclusively as idiosyncratic reactions to a spectrum of medications. Mycoplasma infections may induce some cases of SJS. The mortality in TEN can approach 40% and in SJS it is approximately 5%. The medications that are implicated include:
As the use of medications increases with age these conditions are more frequent in older age groups than in the young.
The onset of SJS/TEN is usually within the first week from the start of antibiotic treatment but the onset may be delayed up to 2 months from the start of anticonvulsant treatment. Usually there is a prodrome resembling an ‘upper respiratory tract infection’ prior to the abrupt onset of a rash consisting of macules, targets and blisters. Initial misdiagnoses are common; however, a few days later the patient appears very unwell and is in severe pain. The typical features of these blisters include the following:
There is extensive involvement of mucosal surfaces and at least two surfaces are involved. These include eyes, lips and oral mucosa, oesophagus, trachea and bronchi, urinary tract, genital mucosa and gastrointestinal tract. Significant ophthalmic lesions occur in both conditions.
The differentiation between SJS and TEN is dependent on the maximal extent of skin detachment and the typical appearance of the rash. In SJS, the skin detachment is <10% of the body surface area (BSA) and in TEN it is usually >30% of the BSA. In the entity called overlap SJS/TEN the skin detachment is between 10–30% of BSA.
Regarding Staphylococcal scalded skin syndrome (SSSS), which ONE of the following statements is INCORRECT?
Answer: D: SSSS is more commonly seen in infants and children younger than 5 years. In adults, the elderly with renal failure are more likely to get affected than others. SSSS is caused by an epidermolytic toxin produced by a strain of Staphylococcal aureus. It is not due to an extensive primary skin infection. Usually the focus of infection may not be significant, that is, it can be a minor skin, nasal or eye infection. Early features are fever and tender erythematous skin. The small blisters coalesce to form large flaccid blisters or bullae that usually burst giving rise to the characteristic appearance of a scalded skin. Nikolsky’s sign is positive. In infants and young children the extensive exfoliation of skin is usually confined to the upper body but in neonates the whole skin surface may be affected.
Similar-looking conditions such as SJS and TEN should be considered in the differential diagnosis; skin biopsy may be required in the differentiation. The skin biopsy will show the subcorneal split in the epidermis. This means these blisters have very thin roofs and therefore break easily. There is no mucosal involvement in SSSS as opposed to what occurs in SJS/TEN. The mainstays of management of these children are intravenous fluid resuscitation similar to a burn patient, prompt initiation of antibiotic therapy to eliminate Staphylococcal focus and supportive care in a specialised burn unit or an intensive care unit.
Which ONE of the following conditions is LEAST likely to cause erythroderma in a patient presenting to the emergency department (ED)?
Answer: A: The term erythroderma describes an inflammatory skin disorder affecting almost the entire BSA and this can be considered as a ‘skin failure’. Erythroderma may be acute or chronic and may often proceeds to exfoliation of skin, hence called exfoliative erythroderma. The patients are often >40 years of age. The causes are varied and generally it is a cutaneous reaction to a medication, underlying systemic or cutaneous illness. The causes include:
The clinical features are generalised erythema without skin tenderness, but with increased warmth, scaling or flaking, pruritus and skin tightness. Erythema starts on the face and spreads downwards to involve most or all of the body. In the assessment, a thorough search should be conducted to identify the underlying cause. As a failure of the skin, erythroderma can cause significant complications including:
Causes of pustules in the skin of a neonate include all of the following EXCEPT:
Answer: C: Neonates may present to the ED with pustular lesions on the skin. Some of these pustular lesions are the only manifestation of serious underlying disease processes in the neonate and therefore the correct identification of these lesions and further assessment of the neonate are important. Other pustular lesions are part of benign transient conditions.
The causes of common pustular lesions in the neonatal period include the following:
Milia are inclusion cysts and not true pustules. They appear commonly in the scalp and the face as white discrete small papules. They can be present at birth or can occur after birth. They usually resolve spontaneously after a few weeks.
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