Dermatology - spot diagnosis + treatments Flashcards
Spot diagnosis: Bilateral blotchy brownish facial pigmentation, associated w sun exposure and hormones
?Treatment
Melasma
Pharm
- Kligman’s formula (combination of hydroquinone, tretinoin and dexamethasone in a cream base)
- Topical depigmenting agents (eg hydrocortisone 1%)
- oral tranexamic acid 500-750mg daily
Non-pharm
- Year round strict sun protection
- Cosmetic camouflage
- Discontinue hormonal contraception if possible
Spot diagnosis: Symmetrical itchy erythematous papules +/- generalised eczematous features +/- nodules, crusting and vesicles, in digit webs and flexures
?Treatment
Scabies
Pharm
- permethrin 5% cream applied to body from neck down, leave on overnight and repeat in 7 days
- benzyl benzoate 25% topically left on for 24 hours
- ivermectin - orally and repeat in 7-14 days
Non-pharm
- hot wash clothing and blankets or put in a sealed bag for 8 days
- contact tracing / treatment
Spot diagnosis: yeast infection (malassezia overgrowth) -> flaky discoloured patches on the trunk, neck +/- arms, usually ASx but may be itchy
?Treatment
Pityriasis Versicolor
Topical (or oral) ketoconazole, or selenium sulfide shampoo
Spot diagnosis: depigmentation of skin due to (?autoimmune) destruction of melanocytes
?Treatment
Vitiligo
Pharm:
- Topical steroids or calcineurin inhibitors
- Topical Vit D
- Oral steroids
Non-pharm
- Phototherapy
- Minimise skin injury
- Cosmetic camouflage
- Sun protection
Spot diagnosis: lace-like (reticular) mottled discolouration, mostly on the legs, often more pronounced in cold weather
?Treatment
Livedo reticularis
May be a temporary physiological response or associated w systemic disease
Cold avoidance
Rewarming
Spot diagnosis: erythematous 2-4mm non-follicular papules and papulovesicles, very itchy, often with surrounding inflammation, often in hot/humid climates
?Treatment
Miliaria (heat rash) rubra
Due to sweat duct obstruction
Non-pharm
- Minimise heat and humidity
- Reduce sweating + irritation
- Calamine lotion + emollient
Pharm
- Mild topical steroids
- Abx if secondary infection
Spot diagnosis: goosebump/chicken skin appearance, small skin-coloured/red/brown bumps which feel rough/dry and may be itchy w surrounding erythema, most commonly on extensor surfaces
?Treatment
Keratosis pilaris
Due to keratin accumulation in hair follicles
Pharm
- Salicylic acid
- Topical retinoids
- Moderate topical steroid for itch
Non-pharm
- Exfoliation
Spot diagnosis: target lesions which develop symmetrically in an acral/extensor distribution +/- mucosal involvement, may be painful/itchy/swollen, commonly precipitated by infection
?Treatment
Erythema multiforme
Precipitating infection usually HSV
May be self-limiting
Oral anti-histamines +/- topical steroids for itch
Refer hospital if severe mucosal disease
Spot diagnosis: tender bilateral erythematous subcutaneous nodules 3-20cm in diameter erupting on the legs +/- arms over weeks w associated fever + joint pain
?Treatment
Erythema nodosum
Hypersensitivity reaction -> inflammation of subcut fat
Treat underlying disease / infection
Rest, NSAIDs, compression +/- systemic steroids if infection/sepsis/malignancy ruled out
Spot diagnosis: intensely itchy symmetrical blistering rash, commonly on the scalp, shoulders, buttocks, elbows and knees
?Treatment
Dermatitis herpetiformis
>90% association w Coeliac disease
Dx: Bx of lesions + Coeliac Ix
Non-pharm
- Life-long GF diet
Pharm:
- Dapsone
Spot diagnosis: annular, smooth, discoloured papules and plaques in the absence of scale
?Treatment
Granuloma annulare
Self-limiting over months +/- potent topical corticosteroids or oral dapsone
Spot diagnosis: inflammatory pustular rash in early life (weeks old) in an otherwise well infant
?Treatment
Neonatal pustulosis
Occurs at time of colonisation by melassazeia yeast (~W3-8 of life)
Self-limiting
Spot diagnosis: pale pink or red indistinct irregular patches present from birth, blanch on compression, typically at the midline
?Treatment
Naevus simplex
Resulting from superficial capillary vascular malformation
Self-limiting +/- consider pulsed dye laser therapy
Spot diagnosis: small inflammatory clusters of skin-coloured to red papules, vesicles, and pustules around the mouth, nose or eyes resembling an acneiform rosacea-like eruption +/- associated features of mild eczematous dermatitis
?Treatment
Perioral dermatitis
Non-pharm
- Avoid trigger (commonly steroids) inc. all facial cosmetic products
- Wash face w warm water alone before introducing a non-soap cleanser
- Moisturise w hypoallergenic non-occlusive emollient
Pharm
- Oral Abx: doxycyline 50-100mg daily or erythromycin (pregnancy) 250-500mg BD for 4-8 weeks; if no response from these trial minocycline 50-100mg daily
- Topical metronidazole 0.75% or clindamycin 1% BD for 4-6 weeks
Spot diagnosis: dry and itchy erythematous patches +/- oozing, crusting and lichenification with a chronic relapsing course, flexural or dorsal distribution
?Treatment
Atopic dermatitis
Non-pharm
- Identify and avoid triggers
- Frequent emollient to improve and maintain skin condition
Pharm:
- Liberal topical corticorsteroids (mild ie. hydrocortisone 1% on face, potent ie. mometasone 0.1% elsewhere)
- Treat secondary infection
