Derm Conditions and ABX Flashcards
Acne, Cellulitis, Erysipelas, Rosacea, Folliculitis
Comedomes tx
Topical Retinoids
Papules, pustules, nodules, and cysts indicate what bacteria?
Gram (+) anaerobes Cutibacterium acnes (P acnes)
Mild acne (papules and pustules) tx
Topical Retinoids + Benzoyl peroxide
Moderate acne (papules and pustules) Tx
Topical Abx— Erythromycin or clindamycin
Severe acne (papules and pustules) Tx
PO Abx— Tetracycline class Doxycycline
Acne Nodules or cysts treatment
Mild/Moderate:
—Topical retinoid + Benzoyl peroxide + topical abx (clindamycin/erythromycin)
Severe:
—PO abx Doxycycline
Treatment for acne that is unresponsive to therapy or is scarring
PO Isotretinoin
Tetracyclines MOA, SOA, and ADRs
MOA: Inhibits bacterial protein synthesis via 30S ribosomal subunit
SOA: broad Gram (+ & -) including MRSA and atypicals (chlamydia, mycoplasma, vibrio cholera)
ADRs: Photosensitivity and esophagitis. Renal except for doxycycline
Contraindicated in kids <8 and in pregnancy/breast feeding
What is rosacea and how does it present?
A chronic Acneiform cutaneous inflammatory rxn.
Face is most commonly involved.
Most common in women ages 30-50yo.
Etiology is unclear:
—Persistent vasomotor instability, capillary vasodilation, and abnormal pilosebaceous activity
Presentation: —Facial flushing of the nose/cheeks/lip margins —+/- telangiectasias —papules and pustules. —Rhinophyma=red enlarged nose
absence of comedomes (blackheads) distinguishes it from acne
Triggers are sun, alcohol, spicy foods, stress, exercise, cold/hot.
Isotretinoin MOA, and ADRs
MOA: affects all 4 of the pathophysiologic mechanisms of acne and is the most effective med for acne vulgaris.
ADRs:
—Dry skin and lips (most common)
—Dry eyes
—Highly teratogenic MUST obtain at least 2 neg pregnancy tests prior to initiation and monthly while on treatment
—Increased triglycerides and cholesterol
—worsening of DM, arthralgias, leukopenia, immature long bone closure
Metronindazole MOA, clinical use, and ADRs
MOA: creates free radicals in bacterial cells that break DNA
Clinical use: Protozoa (amoeba, giardia, trichomonas) and Anaerobes (C diff, Gardnerella, bacterial vaginosis, H pylori)
ADRs: HA, metallic taste, disulfiram like rxn if taken w alcohol use
Clinical Pearl: Clindamycin treats anaerobes _________ and metronindazole treats anaerobes _________
Clindamycin treats anaerobes above the diaphragm and metronindazole treats anaerobes below the diaphragm
What is erysipelas
Variant of cellulitis involving upper dermis: Inflammation of the superficial dermis +/- lymphatic involvement , fever and chills.
Caused by STREP PYOGENES.
A RAISED rash with SHARPLY DEMARCATED BORDERS. Tenderness and warmth
Most commonly involves lower extremities, face, or skin with impaired lymphatic drainage. Can involve ear (Milan sign)
**Unlike cellulitis> this is often associated with systemic manifestations— fever/chills/leukocytosis
Erysipelas Treatment
Outpatient:
— PO Amoxicillin, Penicillin, or Cephalexin. If PCN allergy; Clindamycin, SMX, or linezolid can be used.
If severe w systemic sx:
—IV cefazolin, Ceftriaxone
If MRSA suspected:
—Vancomycin
**if severe/systemic sx get blood culture or US w gram stain of expressed fluid if underlying abscess
Penicillin clinical use and ADRs
Penicillin V= PO
Penicillin G= IV & IM
Clinical use:
—Spirochetes (syphilis)
—Gram + aerobes (Strep Pyogenes)
ADRs: Rash, GI
Aminopenicillins (extended spectrum) Use and ADRs
Amoxicillin/Augmentin= PO or IV Ampicillin= IV
HHEELPSSS broadens PCN SOA:
H pylori/H flu, E. Coli/Enterococci, Listeria, Proteus, Strep Pneumo/Salmonella/Shigella
Use: PUD, bacteria, URIs
ADRs: Rash, diarrhea, C diff super infection
What is Cellulitis and how does it present?
An acute spreading infection of the deeper dermis and subcutaneous tissues. Bacterial entry usually after a break in the skin d/t underlying skin problems/trauma/surgical wounds.
Most commonly GROUP A STREP. Staph Aureus is an important but less common cause
Presentation:
—localized macular erythema with FLAT margins that are NOT sharply demarcated
—Swelling, warmth, and tenderness
—Systemic sx are not common but may develop lymphangitis streaking
Cellulitis Treatment:
Mild/Moderate/Outpt:
—Cephalexin or Dicolxacillin. Clindamycin or erythromycin if PCN allx
—if MRSA concern: Clindamycin, Doxycycline. TMP SMX is good for staph but doesnt cover strep.
Severe/inpt empiric:
—IV Abx: Cefazolin, Ampicillin-sulbactam, Ceftriaxone, & Clindamycin
—IV MRSA: Vancomycin or Linezolid
Cat or dog bite: Cover Pasturella gram (-)
—Augmentin
— Clindamycin + either ciprofloxacin or TMP SMX if PCN allx
What is Folliculitis
Superficial hair follicle infection or inflammation. RF: more common in men, with prolonged abx use or topical corticosteroid use.
STAPH AUREUS most common
PSEUDOMONAS AERUGINOSA for hot tube related folliculitis.
Presents:
— singular or cluster of perifollicular papules and or pustules with surrounding erythema on hair bearing skin.
—often pruritic
Folliculitis Tx
Mild:
— Topical mupirocin, Clindamycin, Erythromycin, or BPO
Severe or Refractory:
— PO Abx: Cephalexin or Dicloxacillin
Gram (-):
—Daily Acetic acid or topical BPO (usually resolves without treatment)
How is Rosacea treated?
—Avoid triggers and wear sunscreen (toners, astringents, menthols, and camphor are irritants)
Mild/Moderate:
— TOPICAL METRONINDAZOLE is first line for papulopustules.
—Azelaic acid, ivermectin cream
— Sulfacetamide, anti acne topical abx
Moderate/Severe:
— Oral abx: Tetracyclines
—Laser therapy
Refractory:
—Oral Isotretinoin may be used
Facial erythema:
—Topical Brimonidine
—Laser or intense pulsed light therapy