Psoriasis, acne, rosacea, pemphigoid and pemphigus Flashcards
Describe the lesions and likely diagnosis. Where are these lesions often found?
Sharply demarcated scaly erythematous plaques
Psoriasis
Extensors, scalp, sacrum, hands, nails
Briefly describe the pathology of psoriasis.
Epidermal hyperplasia and increased turnover
(possibly a complement-mediated attack on keratin layer)
What is the Koebner phenomenon?
Lesions that appear on “trauma lines”
What is the mainstay of psoriasis treatment?
Topical theraipies: vitamin D analogues (e.g. calcitriol), steroids, coal tar
In severe or refractory cases of psoriaris, what treatments can be tried under specialist supervision?
Phototherapy, systemic treatments (immunosuppressants, retinoids, anti-TNF and other biologics)
What is often found in the history of patients with guttate psoriasis?
Strep infection 2-3 weeks previous
Where is acne most often seen?
Across the distribution of sebaceous glands
How is acne treated?
Most resolve themselves
Topical- benzoyl peroxide, Vit A derivatives, antibiotics
Systemic- antibiotics, isoretinoin (can also cause severe flare-ups)
Which skin condition does the picture show? Describe the lesions.
Rosacea
Erythematous lesion with papules and pustules and no comedones
What can rosacea be aggravated by?
Topical steroids
UV
Spicy food
What role does the Demodex mite have in rosacea?
Rosacea may be caused by an allergic reaction to demodex
How is rosacea managed?
Trigger avoidance
Antibiotics (topical metronidazole, oral tetracycline)
Isoretinoin (refractory cases)
Telangiectasia
Surgery/laser shaving for rhinophyma
What is the primary feature of the immunobullous disorders?
Blisters caused by autoantibodies
How are bullous pemphigoid and pemphigus distinguished?
Pemphigoid- the ‘split’ is deeper, within the DEJ
Pemphigus- the ‘split’ is superficial, within the epidermis
Outline the immunopathogenesis of bullous pemphigoid.
Autoantibodies (IgG) against hemidesmosome proteins anchoring the basal cell layer to the basement membrane
