Dermatology Flashcards
What is the classical distribution of flea bite marks?
Below the knees typically, if animals sleep on the bed then can be higher up
How do bed bug bites appear?
Pruritic maculopapular lesions with haemorrhagic punctums
A patient who has just come back from a walking holiday presents with a bulls-eye rash.
What is the technical term for this, and what does it indicate?
Erythema migrans
Tick bite causing Lyme disease
What is the cause of itching with lice?
Agents in louse salivary antigens cause itching
What are the 4 main effects of local corticosteroids?
- Anti-inflammatory
- Immunosuppressive
- Anti-proliferative
- Vasoconstriction
If a flare of a skin issue is controlled by topical steroids, how should the treatment be ceased?
Taper the treatment with less potent steroid once flare-up is under control
What strength of steroid cream should be used on thin or flexural skin e.g. face/groin/scrotum?
Mild or moderately potent steroids
How long should an initial course of topical steroids be prescribed for?
Usually if symptoms do not improve after 3-7 days the condition needs reassessment
How many potencies do topical steroid preparations come in?
4 - mild, moderate, potent, and very potent
What are the mild topical steroids?
Hydrocortisone 0.1%, 0.5%, 1.0% and 2.5%
What is the issue with hydrocortisone 2.5%?
It costs waaaaaaay more than other topical steroids of any other potency
What are the brand names of mild topical corticosteroids?
Dioderm
Mildison
Synalar 1 in 10
What are the commonly used moderate potency topical steroids?
Betnovate RD, Eumovate
What are the commonly used potent steroids?
Generic belcometasone dipropionate 0.025%
Diprosone, Betnovate
What are the very potent topical steroids that are used frequently?
Dermovate
Clarelux
Nerisone forte
How should topical steroids be applied?
-Thin layer
-Once or twice per day
-1 fingertip unit for area the size of two flat hand-prints
What volume of steroid cream should be provided for a 2 week course to cover either face and neck, both hands, genital region, or the scalp?
15-30g
What volume of steroid cream should be provided for a 2 week course to cover both arms?
30-60g
What volume of steroid cream should be provided for a 2 week course to cover both legs, or trunk?
100g
When applying emollient alongside topical steroids, how long should be left between applications?
20-30 minutes
Can pregnant women use topical steroids?
Yes - safest at lowest potencies and on small areas
Can breastfeeding women use topical steroids?
Yes - remove from any breast area with warm water prior to feeding and reapply after feeding
Creams are preferred as they are easier to remove than ointments
What side effects can occur from topical application of steroids?
-Acne vulgaris
-Folliculitis
-Skin atrophy
-Telangiectasia
-Burning/stinging
-Striae
-Contact dermatitis
-Skin depigmentation
-Excessive hair growth
How common are systemic adverse effects of topical steroids?
Rare - more likely if using potent steroid over large area for prolonged period of time
