Dermatology Flashcards
Psoriasis
A: Genetic predisposition, infections cause flares. Linked to smoking, drugs and alcohol. Peaks in teens and 50’s
S: Well demarcated, red scaly patches of the skin. Usually symmetrical and affects the extensor surfaces (where as eczema is itchy and affects flexor surfaces). Scale is often scaly in colour. Nail pitting and oncholysis.
D: - Usually clinical
T: Topical - sunlight, emollients, coal tar preparations, dithranol, topical steroids.
Systemic - Ultraviolet (and psoralen) therapy, methotrexate, ciclosporin.
If none of these work Ustekinumab can be used
Acne vulgaris
T: Mild- topical therapies like benzyl peroxide, topical antibiotics
Moderate - oral antibiotics (e.g 4-6months tetracycline/minocycline) + topical benzyl peroxide.
Severe - 16 weeks oral retionoids (isotretinoin)
Acne rosacea
A: Commonly affects fair skinned individuals betweeb 30-60.
S: Red pustules and papules on nose, forehead, cheeks and chin. May be similar to butterfly rash of lupus. Blushing is worsed by sunlight, spicy foods or alcohol.
D: -
T: Avoid creams and triggers. Oral antibiotics (tetracyclines). If resistant isotetrinoin, laser therapy or surgery are options.
Urticaria
A: Histamine release from mast cells causing fluid release from capillaries. Can be from animal dander, drugs, plants, mould, foods or amoebiasis.
S: Itchy, raised patches airising anywhere on skin (weal - think nettle rash) surrounded by a red flare, lesions can vary in size.
D: Eosinophilia, skin prick or RAST testing
T: Anti-histamines, oral corticosteroids. UVB/PUVA (see psoriasis). Intramuscular adrenaline if airway compromised.
Lichen planus
A: Chronic mucocutaneous disease that affects skin, tongue and oral mucosa.
S: Well define pruritic, planar, purple, polygonal papules. Commonly affects wrists and ankles.
D: Skin biopsy shows lichenoid tissue reaction (thickened epidermis, degenrated cells and lymphocytic infiltration.
T: Potent topical steroids - sometimes oral.
Pityriasis rosea
A: Often follows a viral infection
S: 6 weeks. Begins with a single, scaling patch before further patches appear, most commonly on chest or back in a ‘christmas tree’ pattern. Usually red.
D: Usually clinical but a biopsy may be needed.
T: Not usually needed. Oral anti-histamines or topical steroids may benefit itching.
Pemphigus
A: Peaks at 45-50 YO. IgG antibodies cause painful blistering and erosions.
S: Patients usually present with oral lesions, painful flaccid blisters and mucosal erosions. Nikolsky’s sign (top layers slip away from layers below when rubbed) positive.
D: Punch biopsy with immunofluorescence showing IgG and C3.
T: Systemic corticosteroids
Pemphigoid
A: Autoimmune IgG blisters that commonly affects the elderly.
S: Tense fluid-filled blisters that are very itchy and arise from normal looking skin.
D: Usually clinical, but direct immunofluorescence will reveal IgG and C3.
T: Sterile dressings, oral steroids
Cellulitis
A: Subcut infection, commonest organisms from beta-haemolytic streptococci (strep. pyogenes) and staph. aureus.
S: Erythema, warm, swelling, tender, sepsis.
D: FBC, CRP, imaging to exclude DVT.
T: Elevate affected limb. Usually amoxicillin/benzylpenicillin + flucloxacillin. Alternatives include clindamycin/ceftriaxone
Erysipelas
A: Superficial form of cellulitis, almost always from streptococcus pyogenes.
S: Well defined red area with raised border, skin is swollen and may be dimpled or blistered. Rapid onset pain.
D: FBC, CRP
T: Usually penicillins
Scabies
A: Intensely itchy rash caused by the mite sarcoptes scabiei, spreads through skin contact.
S: Itch, burrows, generalised rash, nodules and blisters on palms and soles of feet.
D: -
T: Anti-scabetic (malathion, permethrin) topical creams for 24 hours.
Tinea
A: Caused by dermatophyte (ringworm) fungus. Second word (e.g tinea manuum) depends on location.
S: Pruritic, inflamed red patches
D: Skin scrapings
T: Topical or systemic antifungals.
Pityriasia versicolor
A: Usually from the malassezia furfur yeast,
S: Flakey, discoloured patches appear mainly on chest and back. Occasionally itches.
D: Usually clinical but skin scrapings may be needed/
T: Topical or oral antifunghals. Selenium sulphide shampoo.
Necrtotising fasciitis
A: Severe cases are by strep. pyogenes, immunocomprimised are at more risk.
S: Infection begins at site of trauma with intense pain. People initially have signs of inflammation, fever and a fast heart rate. With progression of the disease, often within hours, tissue becomes progressively swollen, the skin becomes discolored and develops blisters. Crepitus may be present and there may be discharge of fluid, said to resemble “dish-water”. Diarrhea and vomiting are also common symptoms. Blisters and necrosis may occur.
D: Raised inflammatory markers, blood cultures. MRI/CT shows extent of involvement.
T: Broad spectrum antibiotics and surgical debridement.
