Term
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Definition
| A general term for any purulent infection of the skin |
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Term
| What are some risk factors for pyodermal infections? |
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Definition
| Pre-existing trauma to the skin: mechanical (abrasion, puncture), thermal or chemical – usual route of infection, eczematous lesions, impaired host immunity |
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Term
| What types of bacteria cause pyodermal infections? |
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Definition
| Can be caused by resident flora but is usually not. Primarily caused by Staphylococcus aureus and Streptococcus pyogenes |
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Term
| Where does S. aureus tend to colonize? |
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Definition
| Considered a "transient" flora found in the nasopharynx, axillae, inguinal creases, perineum, toe web spaces |
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Term
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Definition
| Superficial bacterial infection of the epidermis, the most common bacterial infection in children, highly contagious |
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Term
| What are the types of impetigo? |
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Definition
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Term
| What causes non-bullous impetigo? |
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Definition
| More often cause by S. aureus than S. pyogenes, occurs at minor sites of trauma |
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Term
| What are the clinical features of non-bullous impetigo? |
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Definition
| Starts as thin-walled vesicles and pustules on erythematous base which readily rupture,forming a yellow "honey colored" crust, most frequently found on the face, benign, self limiting, tends to resolve in 2 weeks |
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Term
| What is a rare complication of non-bullous impetigo? |
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Definition
| Acute poststreptococcal glomerulonephritis |
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Term
| What causes bullous impetigo? |
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Definition
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Term
| What are the clinical features of bullous impetigo? |
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Definition
| Most common in neonates, small vesicles enlarge to flaccid transparent bullae which rupture and form a shiny varnish of dry erosions, no thick crust |
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Term
| What causes blisters in bullous impetigo? |
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Definition
Exfoliative toxins (A-D) of S. aureus bind to desmoglein 1 (a component of
adhesion protein) in granular layer of epidermis, causes "ungluing" |
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Term
| How is bullous impetigo treated? |
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Definition
| If superficial lesion, Mupirocin 2% ointment, complicated or widespread cases require oral β-lactamase-resistant antibiotic such as Cephalexin or Amoxicillin |
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Term
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Definition
| An ulcerated form of non-bullous impetigo, is a deeper infection, most often seen on lower extremities, heals with scarring |
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Term
| What are the clinical traits of Ecthyma? |
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Definition
| Begins as vescile that ruptures to form thick circular crust, infection underneath the crust penetrates dermis and ulcerates, has "punched out" appearance under crust |
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Term
| What are the characteristics of Staphylococcal Scalded Skin Syndrome? |
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Definition
| Primarily seen in children under 6, caused by S. aureus, high mortality rate if contracted in adults |
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Term
| How does Staphylococcal Scalded Skin Syndrome present clinically? |
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Definition
| Prodrome of malaise, fever, irritability and severe tenderness of skin |
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Term
| Describe the course of progression of Staphylococcal Scalded Skin Syndrome |
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Definition
| Erythema on head -> extends to body -> superficial flaccid bullae -> ruptures giving rise to erythematous base and scalded look -> scaling and desquamation -> skin heals without scarring |
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Term
| What causes blisters in Staphylococcal Scalded Skin Syndrome |
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Definition
Exfoliative toxins A and B of
S. aureus, binds to desmoglein 1 in granular layer of epidermis |
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Term
| How is Staphylococcal Scalded Skin Syndrome treated? |
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Definition
| Extensive form requires hospitalization and parenteral antibiotics, in localized disease treat with β-lactamase-resistant antibiotic |
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Term
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Definition
| Skin infection of the dermis, spreads to dermal lymphatics for regional lymphadenopathy, most common on face/lower extremities, most often caused by Streptococcus pyogenes, complications are rare |
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Term
| What are the clinical features of Erysipelas? |
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Definition
| Abrupt onset of fevers, chills, malaise, nausea, followed by small plaque of erythema, hot/tense indurated skin w/non-pitting edema that is painful to palpation |
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Term
| What is Cellulitis and what is its cause? |
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Definition
| Skin infection involving deep dermis and subcutaneous tissue (like deeper erysipelas), caused by S. aureus and S. pyogenes, commonly infected via break in skin |
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Term
| What are the clinical features of Cellulitis? |
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Definition
| Preceded by fevers, chills, malaise, followed by rapidly spreading erythema, has ill-defined nonpalpable border w/ warmth, pain to palpation, edema, and possible regional lymphadenopathy |
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Term
| How is cellulitis treated? |
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Definition
| Oral antibotic in mild cases, hospitalization and parenteral abxs reserved for serious patients or patients with facial cellulitis |
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Term
| What is folliculitis and what is its cause? |
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Definition
| An infection of the hair follicle, can be either superficial or deep, caused most commonly by S. aureus or Pseudomonas folliculitis, usually benign |
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Term
| What are the clinical features of Folliculitis? |
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Definition
| Superficial folliculitis: small pustules or crusted papules on erythematous base from infection of upper hair follicle, Deep Folliculitis - aka sycosis, large tender erythematous papules with a central pustule due to infection of entire depth of hair follicle |
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Term
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Definition
| Beard area folliculitis with follicular pustules surrounding halo of erythema, caused by trauma from shaving |
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Term
| What is hot tub folliculitis? |
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Definition
| Caused by Pseudomonas aeruginosa, presents as asymptomatic perifollicular papules/pustules seen 1-3 days after exposure to contaminated ater |
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Term
| How is hot tub Folliculitis treated? |
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Definition
| Systemic anti-Pseudomonas antibiotics not recommended, use oral quinolones |
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Term
| What is Pseudofolliculitis Barbae and what is its cause? |
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Definition
| "Ingrown hairs" on cheeks/neck, curved hairs or cut hairs re-enter skin and become ingrown, causing a FB reaction (not an infection), resulting in papules or pustules. Treated with Benzoyl peroxide and clindamycin |
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Term
| What are abscesses and furuncles? |
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Definition
| Nodular "walled-off" collection of pus, furuncle is formed by an abscess that involved hair follicle most commonly caused by S. aureuswhereas an abscess can occur anywhere |
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Term
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Definition
| Contiguous collection of infected follicles (furuncles), extends deeper into subcutaneous tissue, surface has multiple draining sinus tracts, causes malaise, chills fever, is slow to heal and scars |
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Term
| How are furuncles treated? |
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Definition
| Most are self-limited, treating not necessary, responds well to warm compresses, fluctuant lesions can be incised and drained |
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Term
| What is the most common cause of skin and soft-tissue infections in the US? |
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Definition
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Term
| What might make a S. aureus skin infection worse? |
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Definition
| Introducing methicillin resistant S. aureus (MRSA), arose after penicillin was introduced, hospital acquired MRSA is major problem |
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Term
| What gives MRSA its resistance? |
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Definition
| mecA gene which encodes a protein called Peniccillin-binding protein 2A that has a low affinity for beta-lactams, giving it resistance. Hospital acquired MRSA has types I, II, III genotypes, community acquired has type IV genotype |
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Term
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Definition
| Culture, though recurrent MRSA infections can occur in the anterior nares, axillae, perineum, and feet |
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Term
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Definition
| Incision and drainage, oral antibiotics, topical mupirocin |
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Term
| What is Verrucae vulgaris? |
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Definition
| Viral infection which causes common warts caused by HPV type 2 and 4 |
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Term
| What is Verrucae palmares et plantares? |
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Definition
| Viral infection causing warts on hands and feet caused by HPV type 1 |
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Term
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Definition
| Flat warts and plane warts caused by HPV types 3 and 10 |
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Term
| What is Condylomata acuminata? |
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Definition
| Anogenital warts caused by HPV types 6 and 11 |
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Term
| How are cutaneous warts contracted? |
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Definition
| Direct skin contact from contaminated surfaces, tends to appear at sites prone to trauma, periungual regions (nail biting), and can be spread by scratching |
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Term
| How do palmar and plantar warts present clinically? |
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Definition
| Endophytic papules seen on palms, soles, and lateral aspects of hands/feet, gently sloping sides and central depression resembles an anthill, characteristic black spots on surface is a way to distinguish from a corn, may grow inward on soles |
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Term
| What are the clinical features of flat warts (Verrucae Planae)? |
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Definition
| Skin colored or pink to light brown with smooth surface, flat topped papules, tend to be numerous, common around areas of scratching or shaving |
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Term
| What are the clinical features of Conyloma acuminata (anogenital warts)? |
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Definition
| Acquired by sexual contact, caused by HPV 6 & 11, presents as few to numerous small pale pink verrucous or smooth papules or broad based confluent verrucous plaques |
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Term
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Definition
| No treatment is 100%, stimulates immune system to eliminate warts, LN2 and Cantharidin known as "beetle juice" causes blistering, Mediplast (salicylic acid) and topical retinoids |
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