A rash may appear simple but can signal life-threatening illness—from meningococcemia to toxic shock syndrome or Stevens–Johnson syndrome (SJS). The key clinical skill is distinguishing dangerous rashes from common benign conditions.
Your uploaded chart highlights:
- High-risk features
- Dangerous/emergent rashes
- Common rashes
- Diagnostics
- Treatment pathways
- Documentation essentials
This article organizes that information in a clear, academic structure.
Red Flags in Rash
A rash becomes concerning when ANY of the following are present:
Major Red Flags
- Fever
- Toxic appearance
- Extremes of age
- Immunocompromised state
- Rapidly spreading rash
- Petechiae or purpura
- Mucosal involvement (mouth, eyes, genitals)
- Palms/soles involved
- Medication exposures
- Travel history
- Systemic symptoms (AMS, hypotension, joint pain)
A rash with fever + petechiae/purpura is sepsis until proven otherwise.
Dangerous / Emergent Rashes (Must NOT Miss)
These rashes can progress rapidly and require immediate intervention.
1. DRESS / Drug Reaction (Erythroderma)
Clues:
- New medication
- Diffuse rash
- Systemic involvement
- Liver involvement
Workup:
- Sepsis workup
- LFTs
Treatment:
- Stop offending drug
- Supportive care
2. Endocarditis
Clues:
- Fever
- IV drug use
- Murmur
- Janeway lesions
- Osler nodes
- Nail splinter hemorrhages
Workup:
- Duke’s criteria
- TEE
- Sepsis labs
Treatment:
- IV antibiotics
- Surgery if heart failure or shock
3. MAHA / TTP / DIC
Clues:
- Petechiae or purpura
- Toxic appearance
- AMS
Workup:
- CBC, smear
- Hemolysis labs
- DIC panel
Treatment:
- Hematology consult
- TTP → plasmapheresis
Avoid platelet transfusion in TTP unless life-threatening bleed.
4. Meningococcemia
Clues:
- Meningitic signs
- Petechiae/purpura
- Toxic appearance
Workup:
- Sepsis workup
- Lumbar puncture
Treatment:
- IV antibiotics
- Steroids
This is a true emergency.
5. Necrotizing Fasciitis
Clues:
- Severe pain out of proportion
- Bullae / crepitus
- Rapid progression
Workup:
- Sepsis labs
- CT
- CRP / LRINEC
Treatment:
- Immediate surgery
- IV antibiotics
6. Pemphigus Vulgaris
Clues:
- Elderly
- Bullae
- Mucosal involvement
- Nikolsky sign
Workup:
Sepsis screenTreatment:
- Steroids
- Treat secondary infections
7. Rocky Mountain Spotted Fever (RMSF)
Clues:
- Fever
- Petechiae from wrists/ankles → central
- Travel/tick exposure
Workup:
Clinical diagnosis (don’t delay treatment)Treatment:
- Doxycycline
8. Staphylococcal Scalded Skin Syndrome (SSSS)
Clues:
- Fever
- Exfoliation
- Nikolsky positive
- Toxic appearance
Workup:
- Sepsis workup
Treatment:
- IV fluids
- Antibiotics
- ICU
9. Steven-Johnson Syndrome / Toxic Epidermal Necrolysis
Clues:
- Drug reaction
- Mucosal lesions
- Widespread skin sloughing
- Toxic appearance
Workup:
Sepsis labsTreatment:
- Burn unit or ICU
- IV fluids, airway management
10. Toxic Shock Syndrome
Clues:
- Sunburn-like rash
- Fever
- Desquamation
- Tampon use or surgical site infection
Workup:
Sepsis evaluationTreatment:
- IV fluids
- Pressors
- ICU
- Antibiotics
11. Urticaria / Anaphylaxis
Clues:
- Medication or food exposure
- Hives
- SOB, wheezing, throat tightness
Workup:
ClinicalTreatment:
- Airway management
- Epinephrine
- Antihistamines (H1/H2)
Common Rashes (Less Dangerous, More Frequent)
1. Secondary Syphilis
Clues:
- Papular rash
- Palms and soles affected
- STD risk
Workup:
- RPR
- VDRL
- HIV testing
Treatment:
- Penicillin IM
2. Contact Dermatitis
Clues:
- Localized rash
- Exposure to irritant/allergen
Treatment:
- Remove exposure
- Topical steroids
3. Erythema Multiforme
Clues:
- Target lesions
- Drug or infection trigger
Treatment:
- Remove agent
- Supportive
4. Lyme Disease
Clues:
- Tick bite
- Erythema migrans (bull’s-eye rash)
- Bell’s palsy or heart block possible
Workup:
- Lyme titer
- EKG if cardiac symptoms
Treatment:
Doxycycline5. Pityriasis Rosea
Clues:
- Herald patch
- Christmas-tree pattern
Treatment:
- Supportive
- +/- antihistamines
6. Scabies
Clues:
- Intense itching
- Wrist, finger, beltline burrows
Workup:
- Clinical exam
- Skin scrapings
Treatment:
- Permethrin
- Treat contacts
7. Tinea (Dermatophyte infection)
Clues:
- Scaly, raised edges
- Itching
Workup:
KOH examTreatment:
Antifungal cream8. Viral Exanthems
Clues:
- Fever
- Aches
- Mild rash
- Non-toxic patient
Treatment:
Supportive9. Herpes Zoster (Shingles)
Clues:
- Vesicular rash
- Dermatomal distribution
Treatment:
- Acyclovir
- Consider steroids
- Eye involvement → urgent referral
Pearls & Pitfalls (from chart)
These are essential exam points:
✔ Toxic + petechiae/purpura = sepsis until proven otherwise
Think: meningococcemia, DIC, TTP, endocarditis.
✔ Many medications cause rashes
Especially:
- Sulfa
- Penicillin
- NSAIDs
- Antiepileptics
- Chemo agents
✔ Truly emergent rashes
- TTP
- Meningococcemia
- Toxic Shock Syndrome
- DIC
- SJS/TEN
- SSSS
✔ Avoid platelet transfusion in TTP
Unless life-threatening bleeding.
✔ Inspect ALL skin surfaces
Look at palms, soles, scalp, mucosa, nails.
Documentation Essentials
Good documentation includes:
General
- Fever, vital signs, toxic appearance
- Exposures, medications, travel
- PMH (atopy, anaphylaxis, immunosuppression)
Physical Exam
- Distribution
- Palms/soles involved?
- Petechiae/purpura?
- Mucosal lesions
- Lymphadenopathy
Skin Description (Very Important)
- Morphology (macule, papule, vesicle, bullae)
- Color
- Borders
- Presence of sloughing
- Symmetry
Other Exams
- Heart (murmurs → endocarditis)
- Neuro (AMS → TTP, meningitis, sepsis)
Quick Summary Table
| Type | Condition | Key Clues | Treatment |
|---|---|---|---|
| Dangerous | Meningococcemia | Fever, petechiae | IV ABx + steroids |
| TTP/DIC | Petechiae, toxic | Heme consult, no platelets | |
| SJS/TEN | Mucosa, sloughing | ICU/burn unit | |
| Toxic Shock | Desquamation | ICU + pressors | |
| Necrotizing fasciitis | Pain out of proportion | Surgery ASAP | |
| RMSF | Travel + petechiae | Doxycycline | |
| DRESS | New drug + systemic | Stop drug | |
| Common | Contact dermatitis | Exposure | Remove agent |
| Syphilis | Palms/soles | Penicillin | |
| Viral exanthem | Mild fever | Supportive | |
| Lyme | EM rash | Doxycycline | |
| Scabies | Burrows | Permethrin | |
| Pityriasis | Herald patch | Supportive |
FAQs About Rashes
1. When is a rash an emergency?
If the patient has fever, petechiae, shock, mucosal involvement, bullae, or is immunocompromised.
2. Does a petechial rash always mean meningococcemia?
Not always—but it must be ruled out urgently.
3. When do you consult dermatology emergently?
For blistering disorders (SJS/TEN, pemphigus), erythroderma, or rapidly spreading bullous lesions.
4. Does RMSF require confirmatory testing?
No. Treat immediately with doxycycline.
5. Can medications cause life-threatening rashes?
Yes—SJS, TEN, DRESS are classic medication-associated emergencies.
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