A 43-year-old man is admitted to the Emergency Department with a rash and feeling generally unwell. He is known to have epilepsy and his medication was recently changed to phenytoin three weeks ago. Around one week ago he started to develop mouth ulcers associated with malaise and a cough. Two days ago he started to develop a widespread red rash which has now coalesced to form large fluid-filled blisters, covering around 30% of his body area. The lesions separate when slight pressure is applied. On examination his temperature is 38.3ºC and pulse 126 / min. Blood results show:
What is the most likely diagnosis?
Correct Answer D:
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. Some authors consider TEN to be the severe end of a spectrum of skin disorders which includes erythema multiforme and Stevens-Johnson syndrome.
Features:
Drugs known to induce TEN:
Management:
Lesional skin in Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) typically blisters forming vesicles.
Lesional skin in Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) typically blisters forming large flaccid bullae.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Palmoplantar involvement. Multiple circular lesions are present on the palms with Blistering.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Palmoplantar involvement. Multiple circular lesions are present on the soles with prominent Blistering.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Blistering. Lesional skin in SJS/TEN typically blisters forming vesicles.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Blistering. Lesional skin in SJS/TEN typically blisters forming both vesicles and large flaccid bullae.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Individual lesions may coalesce to form large areas of redness, as seen on this patient’s back. In this case, blistering/epidermal detachment was negligible.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Detached epidermis. In SJS/TEN, lesional necrolytic epidermis readily peels back to reveal the dermis.
Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Lip involvement. Severe cheilitis has produced thick haemorrhagic crusts. This SJS/TEN patient had a coagulopathy which resulted in bleeding from the involved mucosae of the mouth and nose.
A 34-year-old man presents to dermatology clinic with an itchy rash on his palms. He has also noticed the rash around the site of a recent scar on his forearm. Examination reveals papules with a white-lace pattern on the surface. Some isolated white streaks are also noted on the mucous membranes of the mouth.
What is the diagnosis?
Correct Answer A: This is a typical history of lichen planus.
Lichen:
Lichen planus
Lichen planus is a skin disorder of unknown aetiology, most probably being immune mediated.
Lichenoid drug eruptions - causes:
Lichen planus. Classic eruption on the volar aspect of the wrist.
Lichen planus induced by mechanical irritation (Koebner phenomenon).
Lichen planus. Close up to show Wickham striae.
An 18-year-old female is reviewed in the dermatology clinic complaining of scalp hair loss.
Which one of the following conditions is least likely to be responsible?
Correct Answer A: Porphyria cutanea tarda is a recognized cause of hypertrichosis.
Alopecia: Alopecia may be divided into scarring (destruction of hair follicle) and non-scarring (preservation of hair follicle).
Scarring alopecia:
Non-scarring alopecia:
*Scarring would develop in untreated tinea capitis if a kerion develops.
A 55-year-old female is referred to dermatology due to a lesions over both shins. On examination symmetrical erythematous lesions are found with an orange peel texture.
What is the likely diagnosis?
Correct Answer A:
Shin lesions: The differential diagnosis of shin lesions includes the following conditions:
Below are the characteristic features:
Erythema nodosum:
Pretibial myxoedema:
Pyoderma gangrenosum:
Necrobiosis lipoidica diabeticorum:
Which of the following skin conditions is not associated with diabetes mellitus?
Correct Answer B: Sweet's syndrome is also known as acute febrile neutrophilic dermatosis has a strong association with acute myeloid leukaemia. It is not associated with diabetes mellitus.
Skin disorders associated with diabetes: Note whilst pyoderma gangrenosum can occur in diabetes mellitus it is rare and is often not included in a differential of potential causes.
1- Necrobiosis lipoidica:
2- Infection:
3- Neuropathic ulcers
4- Vitiligo
5- Lipoatrophy
6- Granuloma annulare*:
*it is not clear from recent studies if there is actually a significant association between diabetes mellitus and granuloma annulare, but it is often listed in major textbooks
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