What is the appropriate management and treatment for a patient presenting with purpura blisters?

Management of Purpura Blisters

Immediately discontinue any potential culprit drug and assess for Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN), as purpuric macules with blisters represent a dermatologic emergency requiring urgent hospitalization and multidisciplinary care. 1

Initial Clinical Assessment

Perform a targeted physical examination focusing on:

• Skin findings: Document purpuric macules, atypical target lesions, blisters, and areas of epidermal detachment using a body map; calculate percentage of body surface area (BSA) involved using the Lund and Browder chart 1
• Mucosal involvement: Examine mouth, eyes, nose, genitalia, and perianal skin for mucositis, blisters, and erosions 1
• Vital signs: Record baseline weight, oxygen saturation, and assess for signs of systemic toxicity or sepsis 1
• Airway patency: Immediately involve anesthesia if any concerns regarding respiratory compromise or need for intubation 1

Critical distinction: If hemorrhagic blisters are present with disproportionate pain, rapid progression, or systemic toxicity, consider necrotizing fasciitis until proven otherwise and obtain urgent surgical evaluation within 6-12 hours 2

Immediate Stabilization

• Discontinue all potential culprit medications immediately, documenting all drugs taken in the preceding 2 months including over-the-counter and complementary therapies 1
• Establish IV access through non-lesional skin when possible and commence fluid resuscitation if clinically indicated 1
• Insert nasogastric tube if patient cannot maintain adequate oral hydration and nutrition 1
• Insert urinary catheter when urogenital involvement is present 1

Essential Investigations

Order the following laboratory studies immediately:

• Complete blood count with differential, C-reactive protein, comprehensive metabolic panel (including urea, electrolytes, liver function tests), coagulation studies, glucose, magnesium, phosphate, bicarbonate 1
• Blood cultures before initiating antibiotics if patient is febrile or septic 1, 2
• Mycoplasma and chlamydia serology, HSV and varicella zoster virus swabs from skin lesions 1
• Chest X-ray 1
• Skin biopsy from lesional skin adjacent to a blister for routine histopathology; second biopsy from perilesional skin sent unfixed for direct immunofluorescence to exclude immunobullous disorders 1
• Bacterial swabs from lesional skin for culture and sensitivity 1
• Serial clinical photography to document progression 1, 3

Blister Management

Do not deroof intact blisters - the blister roof serves as a natural biological dressing that protects against secondary infection 3, 2, 4

For symptomatic blisters requiring drainage:

• Pierce the blister at its base with a sterile needle (bevel up), selecting a site that allows gravity drainage 3, 4
• Apply gentle pressure with sterile gauze to drain fluid 3, 4
• Leave the blister roof intact after drainage 3, 2, 4
• Apply bland emollient (such as 50% white petrolatum and 50% liquid paraffin) to support barrier function and encourage re-epithelialization 3, 4
• Use non-adherent dressings changed with aseptic technique 3, 4

Admission Criteria and Care Setting

Admit immediately to burn unit or ICU if any of the following are present:

• Mucosal membrane involvement or blistering noted on skin examination 1
• BSA involvement ≥10% with epidermal detachment 1
• Signs of systemic toxicity, hypotension, or organ dysfunction 2
• Hemorrhagic blisters with concern for necrotizing infection 2

Convene a multidisciplinary team including dermatology, burn/wound care specialists, ophthalmology (within 24 hours of diagnosis), infectious diseases, and intensive care as appropriate 1

Systemic Treatment for SJS/TEN

For grade 3-4 SJS/TEN (BSA ≥10% or severe mucosal involvement):

• Initiate IV methylprednisolone 0.5-1 mg/kg daily (or 1-2 mg/kg for grade 4), converting to oral corticosteroids on response and tapering over at least 4 weeks 1
• Consider IVIG or cyclosporine for severe or steroid-unresponsive cases 1
• The usual prohibition of corticosteroids for SJS does not apply when the mechanism is immune checkpoint inhibitor-related or T-cell mediated toxicity 1

Infection Prevention and Treatment

• Perform daily cleansing with antimicrobial solution to reduce bacterial colonization 3, 4
• Obtain bacterial cultures before initiating antibiotics if signs of infection are present 3
• Reserve topical antimicrobials for clinically infected areas only - do not apply prophylactically 3
• If necrotizing infection suspected, start empiric broad-spectrum antibiotics covering MRSA, streptococci, and gram-negative organisms (piperacillin-tazobactam + vancomycin + clindamycin) immediately after cultures obtained 2

Monitoring and Follow-up

• Document daily the number, size, and location of new blisters to track disease progression 3, 4
• Provide analgesia prior to dressing changes, as patients commonly report pain or burning 3
• Reassess within 24-48 hours if managed as outpatient to ensure appropriate response 3
• Calculate SCORTEN score to provide prognostic information 1

Critical Pitfalls to Avoid

• Never deroof blisters - this removes the protective biological barrier 3, 2, 4
• Do not apply topical antimicrobials prophylactically to all lesions 3
• Do not delay surgical consultation if hemorrhagic blisters with systemic signs are present 2
• Do not continue potential culprit medications while "observing" the patient 1