Blisters/bullae
no mucosal involvement (in exams at least*): bullous pemphigoid
mucosal involvement: pemphigus vulgaris
Eczema herpeticum describes a severe primary infection of the skin by herpes simplex virus 1 or 2.
It is more commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
Acanthosis nigricans Gastric cancer
Acquired ichthyosis Lymphoma
Acquired hypertrichosis lanuginosa Gastrointestinal and lung cancer
Dermatomyositis Ovarian and lung cancer
Erythema gyratum repens Lung cancer
Erythroderma Lymphoma
Migratory thrombophlebitis Pancreatic cancer
Necrolytic migratory erythema Glucagonoma
Pyoderma gangrenosum (bullous and non-bullous forms) Myeloproliferative disorders
Sweet’s syndrome Haematological malignancy e.g. Myelodysplasia - tender, purple plaques
Tylosis Oesophageal cancer
Otitis externa and blepharitis are common complications of seborrhoeic dermatitis
Pityriasis rosea often follows a viral infection. Streptococcal throat infection tends to trigger guttate psoriasis, dermatophyte fungal skin infection tends to result in pityriasis versicolor.
The treatment of flexural psoriasis differs from extensor psoriasis. The skin of flexure areas of the body is much thinner and more sensitive to steroids compared to the extensor surfaces.
Polymorphic eruption of pregnancy is not associated with blistering
Pemphigoid gestationis, also known as herpes gestationis (despite having no relation to herpes virus infection). This is an autoimmune blistering disorder specific to pregnancy, typically presenting in the second or third trimester. The condition is characterised by intensely pruritic urticarial plaques that progress to tense vesicles and bullae.
Erythema multiforme
Causes
viruses: herpes simplex virus (the most common cause), Orf*
idiopathic
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus
sarcoidosis
malignancy
Children with a new purpuric rash should be admitted immediately for investigations as it may be a sign of meningococcal septicaemia or acute lymphoblastic leukaemia.
