Dermatology Flashcards
Acne Vulgaris
- Due to excess sebum production - increases in puberty
- Open (blackheads) and closed (whiteheads) comedones
- Pustules
- Nodules
- Typically found on the face
Management
- Good Hygeine and Sunscreen
- 1st line Topical Benzoyl peroxide
- 2nd line Topical Abx Clindamycin
- 3rd line topical retinoids (adapeline).
- 4th line: Oral Abx - doxycycline, lymecyline - COCP used in women
a topical azelaic acid + either oral lymecycline or oral doxycycline
- 5th line: Dermatolgy Isotretinoin
Avoid giving Topical or oral Abx due to antimicrobial resistance
- tetracyclines should be avoided in pregnant or breastfeeding women and in children younger than 12 years of age. Erythromycin may be used in pregnancy
- Isotretinoin and topic retinoid is teratogenic avoid in pregs
- A topical retinoid or benzoyl peroxide should always be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance.
Eczema
Atopic Dermatitis
Hx of Atopy
Breastfeeding decreases the risk of childhood eczema
Common triggers: soaps, extreme temperatures, stress, pregnancy
- chronic, inflammatory skin condition break down of skin barrier
- IgE response
- Symptoms often on flexor surfaces
- Pruritus
- Dry skin
Management
- Avoid Triggers
- Emollients - creams, lotions, ointments, e.g. Dermol, E45
These should be used regularly and liberally - Steroid cream, e.g. hydrocortisone, betamethasone
Not to be used on the face
To be used with caution in those under 10 - Tacrolimus (T-cell suppressants) - started by a specialist
Emergency **Eczema herpeticum **
- severe primary infection of the skin by herpes simplex virus 1 or 2.
- It is more commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
- Admit and give IV aciclovir
Basal Cell Carcinoma
Rarely metastasize
- Most common type of skin cancer in the world
- BCCs develop from mutations in the PTCH and TP53 genes
3 Types (often seen on skin exposed sites)
- Nodular BCC - most common, pearly/shiny nodule with raised edges and a depressed centre
- Superficial BCC - patch of scaly, pink skin, common on the trunk
- Morpheaform BCC - poorly defined pale scarring, subtle
Management
- Complete surgical removal - Mohs surgery
- 5-fluorouracil
- Cryotherapy
Burns
- Superficial epidermal First degree Red and painful, dry, no blisters
- Partial thickness (superficial dermal) Second degree Pale pink, painful, blistered. Slow capillary refill
- Partial thickness (deep dermal) Second degree Typically white but may have patches of non-blanching erythema. Reduced sensation, painful to deep pressure
- Full thickness Third degree White (‘waxy’)/brown (‘leathery’)/black in colour, no blisters, no pain
Cellulitis
Eron classification to guide how we manage patients with cellulitis
- Caused by a bacterial infection of the skin often from site of breakage
- Streptococcus pyogenes or Staphylococcus aureus
- Unilateral
- Sudden onset
- Rubor, dolor, tumor, and calor
- Fever & malaise
Management
- Flucloxacillin
Clarithromycin & Erythromycin (pregs) if penicillin allergic - CT if worried about osteomyelitis
- Eron class III-IV: NICE recommend: oral/IV co-amoxiclav, oral/IV clindamycin, IV cefuroxime or IV ceftriaxone
Contact dermatitis
- irritant contact dermatitis: common - non-allergic reaction due to weak acids or alkalis (e.g. detergents). Often seen on the hands. Erythema is typical, crusting and vesicles are rare
- allergic contact dermatitis: type IV hypersensitivity reaction. Uncommon - often seen on the head following hair dyes. Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Topical treatment with a potent steroid is indicated
Cement is a frequent cause of contact dermatitis. The alkaline nature of cement may cause an irritant contact dermatitis whilst the dichromates in cement also can cause an allergic contact dermatitis
Cutaneous fungal infection
Pityriasis versicolor
- caused by Malassezia furfur
- most commonly affects trunk
- patches may be hypopigmented, pink or brown (hence versicolor)
- topical antifungal
Head lice
also known as pediculosis capitis or ‘nits’
- Caused by parasitic insect Pediculus capitis
- eggs hatch in 7 to 10 days
- Spread contact to contact
- itching and scratchinf
- diagnosed using wet comb
- malathion, wet combing, dimeticone, isopropyl myristate and cyclomethicone
Impetigo
- Infection skin condition
- Most commonly caused by S. aureus
- Highly infectious
- Pustules that pop and crust over with a yellow/golden crust
- Itchy
- Not usually painful
management
- 5 day course of hydrogen peroxide 1%
- Topical antibiotics - Mupirocin cream for 7 days
- Oral antibiotics if widespread - flucloxacillin
Children need to be kept off school until the lesions have dried
Good hygiene
Malignant melanoma
Risk factors: male, multiple moles, fair complexion, smoking
- Proliferation of atypical melanocytes with potential for dermal invasion and metastasis
- Common on lower legs in women, and the back in men
- Asymmetrical, irregular, large, evolving skin lesion
- Usually dark colour
Treatment and Management:
* Excision with extended margins
* Chemotherapy if spread to lymph nodes
Breslow Thickness to predict prognosis
Prognosis is good for a Breslow depth of upto 3mm, anything thicker than 3mm has a 5-year survival of 45%
Psoriasis
Risk factors: genetics, smoking, obesity, stress
Chronic Inflammatory Skin Condition
- T-cell mediated abnormal immune response
T cells release cytokines, resulting in keratinocyte proliferation
Features
- Symmetrical, red scaly patches
- Well demarcated plaques
- Typically on extensor surfaces, e.g. elbows
- Itchy
- Nail pitting
- Psoriasis commonly exhibits the Koebner phenomenon; new skin lesions to form at sites of cutaneous injury.
Management - Lifestyle: smoking cessation, weight loss, reduction of stress
- Emollients
- Corticosteroids, e.g. daivobet (steroid and Vit D analogue)
*
Guttate psoriasis occurs in the young, usually following streptococcal infections - discoid scaley macules on the trunk, self-resolves
exacerbate psoriasis:
- trauma
- alcohol
- drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
- withdrawal of systemic steroids
Scabies
- Common parasitic skin disorder
- Caused by a mite - sarcotopes scabiei
- Papular rash - common on the abdomen,
- linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
- Itch that is worse at night
Management
* Treat all household members
* Permetherin ( treatment twice)
Squamous cell carcinoma
Very common skin cancer
Caused due to cumulative exposure to UV light
- Risk factors: smoking, sun exposure, actinic keratosis, age, asbestos, non-solar UV radiation (welders), male
Features
- Solitary nodule - which can bleed
- Firm to palpate
- Can be itchy
- Can be painful
Management
- Surgical excision with extended margins (Mohs micrographic surgery)
- 5-fluorouracil for 4 weeks
BIOPSY & CT to see lymph node involvement
Renal transplant patients - skin cancer (particularly squamous cell) is the most common malignancy secondary to immunosuppression
Urticaria
Urticaria describes a local or generalised superficial swelling of the skin. The most common cause of urticaria is allergy although non-allergic causes are seen.
- pale, pink raised skin. Variously described as ‘hives’, ‘wheals’, ‘nettle rash’
pruritic - non-sedating antihistamines (e.g. loratadine or cetirizine) are first-line
- prednislone in unresolving cases
Mongolian Blue Spot
- Congenital
- Common in those of Asian decent
- Can be mistaken for bruising
- Most common on the lower back
- No treatment needed, fades over time
