Dermatology Flashcards
What is the commonest infective agent of onychomycosis (fungal nail)?
Trichophyton rubrum
What differentials might you give for fungal nail?
Psoriasis
Repeated trauma
Lichen planus
Yellow nail syndrome
What is the management of acne?
- Single topical therapy (topical retinoids, benzoyl peroxide)
- Topical combo therapy (+ antibiotic)
- Oral abx e.g. tetracyclines
a) COCP can be used as an alternative in pregnant women - Oral isotretinoin under specialist supervision
When can patients with impetigo return to work?
After being on treatment for 48 hours
What is the management of venous ulceration which maximises the likelihood of healing?
Compression bandaging
What is the first line management of hyperhidrosis?
Aluminium chloride topical
What are the causes of erythema nodosum?
Infection - strep, TB, brucella Systemic - Sarcoid, IBD, Behcets Malignancy Drugs - Penicillin, sulphonamides, COCP Pregnancy
What is the main complication of actinic keratoses?
SCC
Where would you typically find a pyoderma gangrenosum?
Lower limb or peristomal
What ar the causes of pyoderma gangrenosum?
Idiopathic
IBD
RA, SLE
Myeloproliferation
What is the management of pyoderma gangrenosum?
- Oral steroids
2. Immunosuppressive therapy
What is a side effect of topical side steroids particularly seen in darker patients?
Patchy depigmentation
What are the different steriod potencies and examples of each?
Mild - Hydrocortisone
Moderate - Betamethasone/Clobetasone
Potent - Fluticasone
Very potent - Clobetasol (Dermovate)
What conditions is vitiligo associated with?
T1DM Addison's Autoimmune thyroiditis Pernicious anaemia Alopecia areata
What is the management of vitiligo?
Sun block
Topical steroids if started early
What are the common and important side effects of isoretinoin?
Important - Teratogenicity, low mood
Common - Dry eyes, skin, and lips, raised triglycerides
What are the features of acne rosacea?
Affect nose, cheeks, forehead
Begins with flushing
Telangiectasia are common
Persistent erythema with papule form later one
Rhinophyma and blepharitis are later signs
What is the management of acne rosacea?
Topical metronidazole or PO if more severe disease
High factor suncream
Which drugs might cause worsening of plaque psoriasis?
Beta blockers Lithium Antimalarials NSAIDs ACEi
What endocrine condition can cause acne vulgaris?
PCOS
What disease is dermatitis herpetiformis associated with?
Coeliac disease
How would you differentiate between pemphigus vulgaris and bullous pemphigoid?
Bullous pemphigoid is restricted to the skin, whereas phemphigus vulgaris also involves the mucosa
Where does acanthuses nigricans typically occur?
Axilla, neck, groin (folds)
What is pityriasis versicolor?
A superficial cutaneous fungal infection caused by Malassezia furfur
What are the features of pityriasis versicolor?
trunk involvement predominantly with hypo pigmentation, pink our brown patches.
Often scaly
What are the features of keratoacanthomata?
Volcano or crater like
Initially a smooth dome shaped papule which rapidly grows into a crater filled with keratin
What do ‘exclamation mark’ hairs indicate?
Alopecia areata
What is it important to screen for in patients with alopecia aerate?
Autoimmune disease - thyroiditis, diabetes, pernicious anaemia
What is the first line management of sevorrheic dermatitis?
Ketoconazole topical
When does guttate psoriasis classically present?
After a streptococcal or viral URTI
What factors might exacerbate acne rosacea?
Sunlight
Is dermatitis herpetiformis itchy?
Yis
What is a well recognised side effect of ketoconazole?
Gynaecomastia
Which malignancy is assocaited with acanthosis nigricans
GI Adenocarcinoma
What are the risk factors for SCC?
Sunlight Immunosuppression SMoking Chronic leg ulcers Actinic keratoses
What are the antibodies targeting in pemphigus vulgaris?
Desmosomes
Where are the lesions in HHT/Osler Weber Rendu?
Skin and mucosal membranes
What are the diagnostic criteria for HHT?
Epistaxes
Telangiectasiae at multiple sites
Visceral lesions e/g/ GI telangiectasia or pulmonary nodules
FHx
What topical agent is commonly prescribed on diagnosis of actinic keratoses?
5-Fluorouracil cream for 2-3 weeks
What are the features of lichen planus?
Itchy papular rash on the palms, soles, genitals and flexor surfaces
Polygonal rash
Koebner phenomenon often seen (new lesions at site of trauma)
White lace pattern on buccal mucosa
What is the most common cause of hirsutism and what drug is good in this use?
PCOS
Dianette - Co-cyprindiol (also a COCP)
Peri-orbital and nasolabial scaly rash associated with dandruff =
Seborrhoeic dermatitis
What are the causes of erythema multiforme?
HSV - commonest cause
Idiopathic
Mycoplasma, Strep
Drugs - Penicillin, sulphonamides, carbamazepine, NSAIDs, COCP
CTDs e.g. SLE
Sarcoid
Malignany
What is the management of lichen planus?
Topical steroids are mainstay
Mayrequire oral steroids/immunosuppression if severe
How many skin types are there?
6
What is pityriasis rosea?
An acute self limiting viral rash with a Herald Patch on the trunk followed by erythematous, oval scaly patches which follow the lines of Langer producing a fir tree appearance
What is the disease course of pityrisaisis rosea?
Rash disappears after 6-12 weeks
What are the causes of leukonychia?
Hypoalbuminaemia
Fungal disease
Lymphoma
What is Nikolsky’s sign?
Epidermis separates on mild lateral pressure
Which drugs are known to cause TEN?
Phenytoin Sulphonamides Allopurinol Penicillins Carbamazepine
How would you differentiate telangiectasia from spider naevi?
Telangiectasia refill from the edges, spider naevi refill from the centre
What is leukoplakia and who is it commonly seen in?
White hard spots of the mucous membranes commonly seen in smokers
Is leukoplakia serious?
Yes - premalignant
What are the systemic causes of pruritus?
Liver disease IDA Polycythaemia CKD Lymphoma Thyroid disease
What are some non liver related causes of spider naevi?
Pregnancy
COCP
What are the features of necrobiosis lipodica diabeticorum?
Shiny painless areas of yellow-red skin on the shin of diabetics.
Associated with telangiectasia
Parkinson’s is associated with which skin disease?
Seborrhoeic dermatitis
What is the management of chronic plaque psoriasis?
Regular emolients
1. Topical corticosteroids and VitD analogue for 4 weeks
- If no improvement then up the VitD dose
- Offercoal tar preparation
- Short acting dithranol
What skin disorders are associated with SLE?
Photosensitive butterfly rash
Discoid lupus
Alopecia
Livedo reticular (net-like)
What type of melanoma commonly affects the nail beds?
Acral lentiginous melanoma
What is the difference between lichen planus and lichen sclerosis?
Planus= purple pruritic papular polygonal rash on flexor surfaces
Sclerosus= itch white spots on old ladies vulvae
Where are you most likely to find a keloid scar?
Sternum
What is the mainstay of treatment for bullous pemphigoid?
Oral steroids
