Thread by @Ashka_TxID

#IDBoardPearls #IDtwitter

Derm round ✌🏼. Let’s do this…

Bacterial Skin Diseases. Follow the 🧶

1️⃣ Impetigo: superficial epidermis
🔎- vesicles/pustular ➡️ crust “🍯 yellow”
🦠- GAS, S aureus

‼️ S aureus causes bullous impetigo similar to poison ivy

❓What other skin manifestations does GAS cause? 👇🏼

2️⃣ Erysipelas: upper dermis and superficial lymphatics
🔎- acute, well-demarcated, 😣, erythematous lesion, 🤒
🦠- GAS, B hemolytic strep

3️⃣ Cellulitis: deeper dermis, subQ tissue
🔎- erythema, warmth, edema, not well-

demarcated
🦠- strep (GAS), S aureus

4️⃣ Necrotizing Fasciitis: muscle, fascia, & fat
🔎- initially spares skin, hence, pain out of proportion to PE ➡️ skin crepitus ➡️ discoloration ➡️ bullae ➡️ tissue necrosis ➡️ sepsis, HD instability
🦠- Type I: mixed aerobic & anaerobic

(common after trauma or surgery); Type II: GAS (no air in tissue), MRSA, V vulnificus, Aeromonas

‼️ V vulnificus & Aeromonas associated with 💧exposure & 👇🏼

🚨Myonecrosis: skeletal muscle (“gas gangrene”). Spontaneous w/ C septicum (vs C perfringens) ➡️ (underlying malignancy,

neutropenia, septic abortion, PVD)

5️⃣ Erythema marginatum: 1 of the Jones Criteria for RF along w/ subQ nodules
🔎- pink serpiginous rash, painless, nonpruritic, 💍shaped

❓A pink serpiginous rash is also 👀 w/ cutaneous larva migrans which IS pruritic & caused by?

Answer: Ancylostoma braziliense

6️⃣ Ecythema gangrenosum: superficial dermis. Bacteremia + perivascular infection ➡️ ischemia
🔎- ulcerations on🦵🏼
🦠- Pseudomonas aeruginosa, MRSA

‼️Angioinvasive molds & neutrophilic dermatoses 👇🏼 can cause similar lesions

🚨Sweet Syndrome:

😣 papules/plaques, leukemic infiltrate, often 👀 after G-CSF, 🤒. Causes pathergy

🚨Pyoderma gangrenosum: pustule ➡️ 😣 ulcer with undetermined border & purulent base. Causes pathergy

❓What other syndrome causes pathergy?

Answer: Behçet’s disease

7️⃣ Folliculitis:
🔎- pustule around a hair follicle
🦠- S aureus, P aeruginosa (“hot tub folliculitis”)

8️⃣ Furuncles ➡️ Carbuncles:
🔎- purulent abscess in the subQ tissue
🦠- S aureus

‼️Don’t confuse with Mycobacterim fortuitum, sporotrichosis,

tularemia, nocardia, or cutaneous leishmaniasis

9️⃣ Organism Specific:

Cutaneous anthrax - “Woolsorter’s Disease”
🔎- painless eschar with surrounding edema
🦠- Bacillus anthracis

Erythrasma -
🔎- looks like a fungal or dermatophyte rash. On inguinal areas
🦠- Corynebacterium

minutissimum

‼️which produces coproporphyrin II that fluoresces coral red under Wood’s lamp

Erysipelothrix -
🔎- 😣, violaceous lesion on ✋🏼
🦠- Erysipelothrix rhusiopathiae

‼️Can cause AV IE. Associated w/ occupational exposure to 🦐🦀🐟🐖

Erythema migrans -
🔎- 🎯 lesion

🦠- Borrelia spp

RMSF -
🔎- wrists & ankles ➡️ generalized (including 🤲🏼 &🦶🏼), macular ➡️ petechial ➡️ hyperpigmentation
🦠- R rickettsii

Syphilis -
🔎-
Primary syphilis - painless chancre + LAD
Secondary syphilis - papulosquamous, nonpruritic rash +/- alopecia

(“moth-eaten cranium”), oral lesions (“snail track ulcers”), condyloma lata, keratoderma blenorrhagicum, lues maligna (“malignant syphilis” 👀 with HIV)

❓ Keratoderma blenorrhagicum is also 👀 with what?

Answer: reactive arthritis

Check out this 🧵by @DrStevenTChen It’s really helpfully in distinguishing some of these skin diseases #dermtwitter
👇🏼

https://twitter.com/DrStevenTChen/status/1169077384236228608

And test your knowledge with photo quiz by @TAEscmid

https://twitter.com/TAEscmid/status/1134402124354347010