Scabies, Lice, Boils, Impetigo, Burns, Photosensitivity, Wound Healing Flashcards
What is scabies
Infestation of the skin with the mite that can be transferred person to person through physical contact or animals
What are the symptoms of scabies
Pruritic lesions that are worse at night with erythematous papules and burrows in web areas of hands, wrists, waistline and genitals
Lasts up to 3 weeks even after treatment despite killing of mites (droppings)
What are the different form of scabies
- Classic scabies: erythematous papules that appear in finger web spaces, wrists, elbows and axillary folds
- Crusted scabies: due to impaired immune system
- Nodular scabies: more common in infants and young children- due to hypersensitivity
- Bullous scabies: occurs in children and elderly
- Scalp scabies: occurs in infants
- Scabies incognito: wide atypical form
How do you treat scabies
Permethrin (1st line)
Apply to entire body from neck down and wash off after 8-14 hours
Repeat treatment after 7 days
Lindane not recommended in children (<2 years)
Ivermectin
What population do lice commonly affect and what area of the body
Girls between 5-11
Affect SCALP , PUBIC HAIR (crabs) and eyelashes
What are the symptoms of lice
Intense pruritus caused by bites on shoulder, abdomen and buttocks
How do you remove head lice
- mechanical removal: use of nit comb to comb back wet hair (scalp) at 4 day intervals
- Dimeticone (4%) for dry hair and scalp, allow to dry naturally, wash off after 8 hours. Repeat after 7 days.
- Malathion (0.5%): apply to dry hair and scalp, allow to dry naturally, wash off after 12 hours. Repeat after 7 days.
How do you remove pubic (crabs) lice
- Malathion (0.5%): apply over body and wash over naturally after 12 hours
- Permethrin: apply 5% cream all over body, dry naturally, leave for 12 hours or overnight then wash off
What are furuncles and carbuncles, and causes
Furuncles: infected spot found on face or nose mainly
Carbuncles (multiple furuncles): commonly found on buttocks, breasts, face and neck
Causes: Staphyloccocus infection
How do you treat boils like furuncles
Topical antibiotics for small area
Larger regions use of systemic antibiotics for patients with expanding cellulitis or immunocompromised
Application of soap containing containing CHLORHEXIDINE GLUCONATE with ISOPROPYL ALCOHOL or 2-3% CHLOROXYLENOL
What is impetigo and ecthyma
- A superficial skin infection that causes crusting caused by streptococci and staphylococci
- Ecthyma: ulcerative form of impetigo, punched out like ulcers with thick, brown and black crusts
What are the symptoms of impetigo
- Clusters of vesicles, pustules that rupture or development of honey coloured crust
- Mild discomfort or pain
How do you treat impetigo and ecthyma
- Fusidic acid (2%)
- Mupirocin (2%)
- Oral antibiotics: Flucloxacillin and clarithromycin
What can photosensitivity lead to symptom wise and how do you treat it
Symptoms: Redness, urticaria, rash: all occurs within minutes of sunlight exposure
Treatment: Sunlight induced following cosmetic use (topical corticosteroids and avoiding causative agents)
How do drugs induce photosensitivity/toxicity
Light absorbing compounds directly generate free radicals and inflammatory mediators
What drugs typically cause phototoxic reactions
- Acne drugs: Isotretinoin
- Antibiotics: Tetracyclines, trimethoprim, quinolone, sulphonamides
- Tricyclics
- Griseofulvin
- Sulphonylureas
- Antipsychotics
- Diuretics: Furosemide, thiazides
- Cardiovascular drugs; Amiodarone
- Topical preparations: antibacterial (chlorhexidine), antifungals, coal tar, fragrances
What is a burn
Injuries to skin or tissue caused by thermal, radiation, chemical or electrical contact
What causes chemical burns
Strong acids or alkalis
Phenols or cresols
Skin and deeper tissue necrosis
What causes thermal burns
Liquids, flames, solids, gases and object
What is the end result of a burn
Protein denaturation and coagulation necrosis
Platelet aggregation
Vessel constricting around coagulated tissue
Skin necrosis
Inflammation in inflamed region and infection due to epidermal layer - leads to oedema and external fluid leakage
Thermoregulation of damaged dermis leads to impaired heat loss and fluid leakage and increased evaporative heat loss
What is a first degree burn
- Red rash, blanching marked with light pressure, painful and tender
- LIMITED TO EPIDERMIS
What is a second degree burn
Involves part of dermis: Superficial and deep
- Superficial: upper half of dermis that heals within 2-3 weeks
Skin is: red and white, blanches with pressure
Vesicles develop - Deep: bottom half of dermis
3 weeks to heal: common scarring
What is a third degree burn
Full thickness
Extends over all layers and into underlying fat
How do you treat burns
- Examination of Airway, breathing and circulation
- Removal of any clothing that covers burns
- Flush chemicals with water for at least 20 minutes (if involves acid and alkalis)
- Small burns: immersed with cold water until pain subsides
- After cleansing wound: application of topical antibacterial salve (silver sulphadiazine 1%) and sterile dressing
- Dressings are changed daily and cleaned with water
- Surgery grafting is for all third degree burn and ones that do not heal within 3 weeks
What is a skin mesh
Skin taken from area like thigh and meshed to cover a large wound
Example: 5cm2 area of thigh, meshed to cover 10-20cm2 wound
What is abrasion
graze, superficial epidermis layer removed off
What is laceration
Irregular tear
What is avvulsion
Removal of all skin layers by abrasion
What are the four types of wounds and explain them
- Necrotic
Dead (ischemic) tissue: black and covered with epidermis - Sloughy
Yellow due to accumulation of cellular debris, fibrin, serum exudate, bacteria - Granulating
Typically deep pink or red with a highly vascularised irregular granular appearance - Epithelising
Cells migrating from wound edges to start process of re-epithelisation
Describe haemostasis
- Injury
- Vasoconstriction
- Platelet aggregation
- Coagulation Cascade PF3 (platelet factor 3)
- Haemostats plug/clot seal damaged vessel
Describe Inflammation
- Redness, swelling, heat and pain: caused by capillary blood system, blood system increasing circulation and underlaying epithelial growth
- Initiate wound healing through wound stabilisation via platelet activity (stops bleeding and triggers immune response)
- Within 24 hours of initial injury: neutrophils, monocytes, macrophages: controls bacterial growth and removes dead tissue
Describe proliferation
Begins 24 hours after injury and can last up to 21 days
Characterised by epithelialisation, granulation, collagen synthesis
What is granulation
- Formation of new capillaries that generate and feed new tissue (angiogenesis)
- Creation of beefy looking tissues that bleed easily
- Fibrous connective tissue (replace fibrin clot)
- Grows from base of wound
What is epithelialisation
Formation of epithelial layer that seals and protects the wound
Needs a moist environment
What is collagen synthesis
Creates a new support matrix that provides tissue its strength
Essential: oxygen, iron, vitamin C, zinc, magnesium and protein
Actual rebuilding of barrier
What is wound contraction
Occurs one week after post injury when skin starts to align itself along collagen to grow out
Larger wounds can be 40-80% smaller after contractions
Describe maturation
Final wound healing stage: collagen synthesise and degradation
Replaces collagen type 3 made at proliferation with a stronger type 1 version
Disorganised collagen fibres are rearranged, cross linked and aligned across tension lines
What is primary wound healing
Wounds are bought together so they are adjacent to each other
performed with sutures, staples or adhesive tape
Minimises scarring and infection risk
What is secondary wound healing and the advantages/disadvantages
Wounds can granulate
Granulation results in broader scar than primary intent
Advantages: removal of foreign bodies, prevents haemotoma development
Disadvantages:
Healing can be slow due to drainage from infection
What is tertiary healing
Healing by purposely leaving the wound open
Initially cleaned, debrided (removal of dead, damaged, infected tissue)
Phagocytosis occurs, epithelialisation, collagen deposition, maturation occurs
Wound is normally closed after 4-5 days
What is a scar
Part of natural healing process
Formed due to collagen, sweat glands, hair follicles do not grow back
Wound does not clear normally
What is a hypertrophic scar
Overproduction of collagen: causes scar to be raised above skin
Typical red raised lump on skin
What is a keloid
Overgrowth of collagen forming shiny nodules that can be pink, red or brown
Caused by surgery, accident, acne or body piercings
Harmless can be itchy or painful though
What is a atrophic scar
Sunken recess in the skin with a pitted appearance
Cause: underlying structure supporting the skin (fat and muscle) are lost
Associated with: acne, chicken pox
