Cutaneous Infection - Bacterial Derm Infections Flashcards
Bacterial Skin Infections
Key Points
Skin has balance of normal flora vs pathogenic flora
Impetigo
Furuncles
Carbuncles
we all have some in the skin , only a problem when pathogenic
Impetigo Contagiosa
(Non-Bullous
Impetigo)
Contagious!
Dermatological trauma or previous lesions predispose patient
Causative organism:
Staphylococcus aureus (most of the time) - a lot of us are carriers, more common
Individual may be carriers (nares andperineum)
Streptococcus pyogenes
The first sign of impetigo is a patch of red, itchy skin. Pustules develop on this
area, soon forming crusty, yellow-brown sores that can spread to cover entire areas of the face, arms, and other body parts. Most patients are children.
Honey crusted lesions develop where vesicles have popped
Treatment is by antibiotics
Bullous
Impetigo
The more serious form of impetigo Affects the dermal layer of the skin Blisters are painful and may turn into ulcers “large flaccid bullae” Bullae burst sand leaves a varnish like crust Swollen lymph nodes may be present
once they breakdown, skin under breaks down too and you can get ulcers that are harder to heal
Treatment for Impetigo
Impetigo is considered self-limiting (~2-3 weeks to heal) but antibiotics
provide quicker resolution and prevents the spread
Bullous form I always refer!!
Topical antibiotics work well if lesions are limited to 2-3 spots
Refer for systemic antimicrobial treatment if:
Patient has systemic symptoms
Widespread disease
Immunocompromised
Renal disease
Valvular heart disease
No improvement with topical treatment
Topical Antibiotics
for impetigo
Nonprescription polymixin B +/- bacitracin +/- gramicidin (Polysporin® products)
Prescription Fusidic acid 2% (ointment or cream) Mupirocin 2% (ointment)
Applied 2-3 times a day for 7-10 days or
until all lesions healed . Lesions start to
heal within 3 days of therapy
Nonpharmacological
Therapy for impetigo
In conjunction with topical antibiotic!
Remove crust with warm compress
Do not manipulate/pick at lesions!
Folliculitis, Furuncles &
Carbuncles
Folliculitis
Due to S. aureus most often
Inflammation of the hair follicles
Caused by bacteria, yeast or fungus
Furuncles - folliculitis that got more deeper and inflamed
“Boil”
Deeper infection (dermis) of the hair follicle often due to S. aureus
Painful, erythematous swelling, central pustule
Pus drains spontaneously
Carbuncle
Red, swollen, and painful ‘cluster of boils’ that are
connected to each other under the skin (adjacent
follicles)
Penetrate deeper than furuncle
Due to S. aureus most often
Patient may present with systemic symptoms (fever,
malaise)
Treatment
66
Folliculitis and furuncle:
Will spontaneously rupture - get the infection out
Warm water or saline compresses to promote drainage
Wash area with soap and water to decrease bacterial
colony
Cover with sterile dressing (furuncle)
Wash items touching lesion daily
Treatment
67
Carbuncle
Needs to be incised (refer!!!)
May require systemic antimicrobial treatment by
physician (do not have to memorize oral antibiotic
names for this course and topic)
Cellulitis (when a furuncle or
carbuncle is out of control!)
Cellulitis is a spreading bacterial infection of the skin and tissues beneath the skin
Staphylococcus and Streptococcus are usually responsible for cellulitis, although many types of bacteria can cause the condition
Sometimes cellulitis appears in areas where the skin has broken open, such as
the skin near ulcers or surgical wounds.
Symptoms and signs include redness, tenderness, swelling, and warmth of the
affected area
Cellulitis is not contagious
Cellulitis is treated with oral or intravenous antibiotics
erisypelas if on face
Onychomycosis is an
Infection
Progressive
Recurring
Transmittable
Can have serious local and systemic sequelae
As with any infection, it needs to be treated!
Half of nail disorders are probably fungal
Primarily affects toenails
May coexist with other nail disorders (psoriasis)
Prevalence increases with age
More common in diabetics
Diagnosis of Onychomycosis:
Patient History
Duration of nail changes
Any previous treatment and effect thereof
Personal and family histories of skin,
hair or nail disease
Psoriasis, lichen planus, other rashes, Down’s
syndrome
Personal history of other relevant conditions
Trauma, lifestyle, advanced age, medication,
circulatory dysfunction, neuropathy, immune
compromise,
recurrent cellulitis, diabetes
Degree of impact of infection
Diagnosis: Clinical Symptoms
Thickening of nail bed and nail plate Subungual debris Onycholysis Nail Discoloration Nail pitting (consider psoriasis, alopecia areata, etc.)
Differential Diagnosis
Nail alterations similar to onychomycosis can
develop due to a number of other causes
Differential diagnosis: ̶ Psoriasis ̶ Reiter’s syndrome ̶ Norwegian scabies ̶ Lichen planus ̶ Pachyonychia congenita ̶ Bowen’s disease ̶ Chronic dermatitis ̶ Pityriasis rubra pilaris ̶ Darier’s disease ̶ Erythroderma ̶ Acrokeratosis paraneoplastica ̶ Squamous cell carcinoma
Onychomycosis: Diagnosis
see sldie 78
take a nail clipping and send for testing
1. lab looks under microscope Direct Microscopy
• Screening test for presence
of fungi
• 5-15% false negatives due to sparsely present hyphae (fungal filaments)
- culture (Can often have false negatives)
(Only method to identify causative fungi)
Selctive media toidentify dermatophytes
