I have a cutaneous eruption that started on my legs and has now spread to my chest; what is the appropriate management?

Management of Spreading Cutaneous Eruption from Legs to Chest

The appropriate management depends critically on establishing whether this is a drug-induced eruption (particularly if you're on anticancer therapy), an infectious process, or another etiology—but in the absence of specific context, initiate gentle skin care measures immediately while pursuing urgent diagnostic evaluation.

Immediate Diagnostic Considerations

The pattern of a rash starting on the legs and spreading to the chest requires systematic evaluation based on morphology and associated symptoms 1:

• If you are taking anticancer medications (EGFR inhibitors, MEK inhibitors, or mTOR inhibitors), this distribution pattern is consistent with papulopustular exanthema, which characteristically begins in sebaceous-rich areas and can progress to the chest 2
• If pustules are present, consider drug-induced eruptions, bacterial superinfection, or generalized pustular conditions 3
• If the rash respects the face (sparing facial involvement), this pattern suggests specific etiologies requiring targeted management 4

Initial Management Strategy

For Drug-Induced Papulopustular Eruptions (Grade 1-2)

If you are on anticancer therapy and the rash covers 10-30% of body surface area:

• Continue your current medication dose and initiate oral tetracycline antibiotics for at least 6 weeks: doxycycline 100 mg twice daily OR minocycline 50-100 mg daily 2
• Apply topical low-to-moderate potency corticosteroids (hydrocortisone 2.5% or alclometasone 0.05%) twice daily to affected areas 2
• Reassess after 2 weeks—if the rash worsens or fails to improve, escalate to grade 3 management 2

For Severe Eruptions (Grade 3 or >30% Body Surface Area)

• Interrupt the causative medication until the rash improves to grade 1 or less 2
• Obtain bacterial, viral, and fungal cultures if infection is suspected (painful lesions, yellow crusts, purulent discharge, or failure to respond to antibiotics) 2
• Initiate systemic corticosteroids: prednisone 0.5-1 mg/kg body weight for 7 days with tapering over 4-6 weeks 2
• Continue oral tetracyclines for at least 6 weeks 2

Essential Skin Care Measures (For All Patients)

Regardless of etiology, implement these protective measures immediately 2, 5:

• Avoid frequent washing with hot water (showers, baths, hand washing) 2
• Discontinue all skin irritants: over-the-counter anti-acne medications, harsh soaps, solvents, and disinfectants 2, 5
• Apply alcohol-free moisturizers containing 5-10% urea at least twice daily to maintain skin barrier function 2, 5
• Use broad-spectrum sunscreen (SPF 15 minimum) on all exposed areas, reapplying every 2 hours when outdoors 2
• Avoid excessive sun exposure 2

When Bacterial Superinfection is Suspected

Obtain bacterial cultures BEFORE starting antibiotics if you observe 2, 5:

• Failure to respond to oral antibiotics covering gram-positive organisms
• Presence of painful skin lesions
• Pustules extending to arms, legs, and trunk
• Yellow crusts or purulent discharge
• Systemic signs (fever, malaise)

Administer culture-directed antibiotics for at least 14 days based on sensitivities 2

Critical Pitfalls to Avoid

• Never use topical corticosteroids as monotherapy if fungal infection (tinea corporis) is suspected, as this facilitates fungal spread and creates "tinea incognito" 6
• Do not apply topical anti-acne medications to pustular rashes, as these are irritants that worsen inflammation 5, 4
• Avoid tight-fitting or occlusive clothing over affected areas, as this augments systemic absorption of topical steroids and may worsen the eruption 7

Urgent Referral Criteria

Seek immediate dermatology consultation if 5, 4:

• Grade 3-4 severity rash (>30% body surface area involvement)
• Systemic symptoms present (fever, malaise, hypotension)
• Suspected autoimmune skin disease
• No response to first-line treatment after 2 weeks
• Need for skin biopsy for definitive diagnosis
• Uncertain diagnosis despite initial evaluation

Special Considerations

If you develop signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (widespread purpuric macules, flat atypical targets, skin shearing, or mucosal involvement), this represents a medical emergency requiring immediate hospitalization 2. These conditions can progress rapidly and carry significant mortality risk.

For patients with HIV or immunocompromise, consider eosinophilic folliculitis if severely pruritic sterile pustules develop on the chest and proximal extremities 3.