What is the appropriate work‑up for a patient presenting with burning skin on the side?

Work-up for Burning Skin on the Side

Begin with a focused history to determine the distribution, duration, and associated symptoms of the burning sensation, followed by a complete skin examination to identify any visible lesions, erythema, or vesicles that would guide further diagnostic testing.

Initial Clinical Assessment

History Taking

The history should focus on specific elements that differentiate between dermatologic, neurologic, and systemic causes 1, 2:

• Onset and duration: Sudden onset suggests acute dermatitis, drug reaction, or herpes zoster; gradual onset may indicate neuropathic pain or chronic skin conditions 3
• Distribution pattern: Unilateral dermatomal distribution strongly suggests herpes zoster; bilateral suggests systemic causes 1
• Character of burning: Constant burning with visible skin changes suggests dermatologic pathology; burning without visible changes suggests neuropathic pain 4
• Associated symptoms: Fever, malaise, or systemic symptoms raise concern for drug reactions or infections 4
• Medication history: Document all medications started within the past 2 months, including over-the-counter and herbal products, as drug reactions can present with burning dysesthesia 5
• Trauma or thermal exposure: Recent burns require specific cooling and wound care protocols 4, 6

Physical Examination

Perform a systematic skin examination focusing on 4:

• Inspection of the affected area: Look for erythema, vesicles, bullae, erosions, scaling, or atypical targets that would indicate specific diagnoses 4
• Palpation: Assess for warmth, tenderness, and texture changes 2
• Distribution mapping: Document the exact body surface area involved and whether it follows a dermatomal pattern 5
• Mucous membrane examination: Check eyes, oral cavity, and genitalia for erosions or inflammation, which would suggest Stevens-Johnson syndrome or other severe cutaneous reactions 4, 5
• Lymph node examination: Palpate regional lymph nodes for enlargement 4

Diagnostic Algorithm Based on Clinical Findings

If Vesicular Rash in Dermatomal Distribution

• Clinical diagnosis: Herpes zoster is likely 4
• Confirmatory testing: HSV/VZV PCR from vesicle fluid if diagnosis uncertain 5
• No further workup needed if classic presentation 4

If Burning Without Visible Lesions

This suggests neuropathic pain (dysesthesia) 4:

• No laboratory testing required for isolated dysesthesia 4
• Consider: Postherpetic neuralgia if history of prior zoster, or vulvodynia/penile dysesthesia if genital location 4
• Management: Trial of topical lidocaine 5% ointment; if ineffective, consider amitriptyline 4

If Erythema with Blisters or Erosions

This requires urgent evaluation for severe cutaneous adverse reactions 4, 5:

• Immediate actions: Calculate percentage of body surface area involved; examine all mucous membranes 5
• Laboratory workup: Complete blood count, C-reactive protein, comprehensive metabolic panel, coagulation studies 5
• Skin biopsy: Obtain punch biopsy with direct immunofluorescence to differentiate bullous disorders from Stevens-Johnson syndrome 4, 5
• Dermatology consultation: Urgent if >10% body surface area or mucous membrane involvement 4, 5

If Erythematous Patches or Plaques Without Blisters

• Skin biopsy: Perform punch biopsy including deep reticular dermis to evaluate for inflammatory dermatoses or malignancy 4
• Consider: Contact dermatitis, eczema, psoriasis, or early cutaneous lymphoma depending on morphology 4
• Patch testing: If contact dermatitis suspected 4

If Suspected Thermal Burn

• No laboratory testing needed for superficial burns 4, 6
• Immediate cooling: Apply clean running water for 5-20 minutes 4, 6
• Wound care: Apply petrolatum-based ointment and nonadherent dressing 4, 6
• Seek medical evaluation: All facial burns and burns >10% body surface area require hospital assessment 6

Red Flags Requiring Immediate Escalation

Transfer to emergency department or burn center if 4, 5:

• Epidermal detachment >10% body surface area with systemic symptoms 5
• Mucous membrane involvement with skin blistering (concern for Stevens-Johnson syndrome) 4, 5
• Fever, hypotension, or altered mental status with skin findings 5
• Rapidly progressive skin changes over hours 5

Common Pitfalls to Avoid

• Do not dismiss burning without visible lesions as purely psychological; neuropathic dysesthesia is a real entity requiring specific treatment 4
• Do not delay dermatology consultation when blistering or erosions are present, as early intervention in severe cutaneous reactions reduces mortality 5
• Do not perform extensive laboratory testing for isolated burning sensation without skin findings; history and examination are sufficient 4, 1
• Do not apply ice directly to burns; use clean running water or ice wrapped in cloth only 4, 6
• Do not biopsy superficially if infiltrative process suspected; include deep reticular dermis 4