dermatology 2 Flashcards
what is Porphyria cutenea trade?
Porphyria cutanea tarda is the most common hepatic porphyria. It is due to an inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, hepatitis C, oestrogen.
what are the features of Porphyria cutinea tarda?
classically presents with photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
hypertrichosis
hyperpigmentation
photosensitivity
What are the investigations for porphyria cutanea tarda?
urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
serum iron ferritin level is used to guide therapy
How is Porphyria cutaneea tarda managed?
chloroquine
venesection
preferred if iron ferritin is above 600 ng/ml
what is epidermolysis bullosa?
a group of inherited disorders characterized by skin fragility and blistering following minor trauma.
what is Necrobiosis diabeticorum?
shiny, painless areas of yellow/red skin typically on the shin of diabetics
often associated with telangiectasia
What is Erythema ab igne?
Erythema ab igne is a skin disorder caused by over exposure to infrared radiation.
what are the characteristics of erythema ab igne?
reticulated, erythematous patches with hyperpigmentation and telangiectasia.
A typical history would be an elderly women who always sits next to an open fire.
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
What is Hereditary hemorrhagic telangiectasia?
Also known as Osler-Weber-Rendu syndrome, hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes. Twenty percent of cases occur spontaneously without prior family history.
What are the 4 main diagnostic criteria for hereditary haemorrhage telangiectasia?
If the patient has 2 then they are said to have a possible diagnosis of HHT. If they meet 3 or more of the criteria they are said to have a definite diagnosis of HHT:
epistaxis : spontaneous, recurrent nosebleeds
telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
family history: a first-degree relative with HHT
what is Pityriasis rosea?
a self-limiting, exanthematous skin disorder of unknown aetiology, commonly affecting young adults and adolescents
what is pityriasis rosea characterised by?
The condition is characterized by the acute onset of a solitary, oval-shaped herald patch, followed by the development of smaller erythematous papulosquamous lesions in a characteristic ‘Christmas tree’ distribution along the Langer’s lines. Pruritus may be present and can range from mild to severe in intensity. Pityriasis rosea typically exhibits a benign clinical course, with spontaneous resolution occurring within 6-8 weeks.
what is pityriasis rosea thought to be associated with?
current evidence suggests an association with human herpesvirus (HHV) 6 and HHV-7 reactivation.
What is the management for Pityriasis Rosea?
Management consists of symptomatic relief through antihistamines for pruritus control and topical corticosteroids or calcineurin inhibitors for inflammation reduction
UV therapy can be used in severe or persistent cases
