What could be causing skin tenderness to touch in a patient, considering their age and medical history?

Skin Tenderness to Touch: Differential Diagnosis and Management

Immediate Diagnostic Considerations

Cutaneous pain is a prominent early feature in Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), and the presence of this symptom should alert the physician to incipient epidermal necrolysis. 1

Critical Red Flags Requiring Urgent Evaluation

• Lesional skin that is tender to touch with minimal shearing forces causing epidermis to peel back suggests SJS/TEN, which is a dermatologic emergency requiring immediate specialist referral 1
• Severe pain disproportional to clinical findings, failure to respond to initial antibiotic therapy, hard wooden feel of subcutaneous tissue, systemic toxicity with altered mental status, edema or tenderness extending beyond cutaneous erythema, crepitus, bullous lesions, or skin necrosis/ecchymoses all suggest necrotizing fasciitis, which requires emergency surgical intervention 1
• Prodromal pain preceding visible skin lesions by several days, particularly in a dermatomal distribution, strongly suggests herpes zoster 1, 2

Primary Differential Diagnosis Based on Clinical Presentation

If Widespread Tender Skin Without Visible Lesions:

• Begin with high-lipid emollients applied twice daily plus 1% hydrocortisone cream twice daily for 2 weeks to treat asteatotic eczema (xerosis-related eczema), which is the most common cause of generalized pruritus and skin tenderness in elderly patients 2, 3
• Add a non-sedating antihistamine (fexofenadine 180 mg daily or loratadine 10 mg daily) for symptomatic relief 2, 3
• Never prescribe sedating antihistamines (diphenhydramine, hydroxyzine, chlorpheniramine) due to increased risk of falls, confusion, and potential contribution to dementia, particularly in elderly patients 2, 3

If Tender Skin With Erythema and Fever:

• Immediately evaluate for SJS/TEN if atypical targets, purpuric macules, or confluent erythema are present, especially if there is recent medication exposure (typically within 1-3 weeks) 1
• The Nikolsky sign (gentle lateral pressure causing detachable epidermis to slide over dermis) is a helpful clinical indicator of epidermal necrolysis, though not specific for SJS/TEN 1
• Facial erythema, upper torso, proximal limbs involvement with progression to trunk and distal limbs, particularly with prominent palmar and solar involvement, characterizes SJS/TEN 1

If Unilateral Tender Skin:

• Look for any vesicles, even subtle ones, as herpes zoster classically presents with grouped vesicles on an erythematous base in a dermatomal distribution, though early presentations may show only erythema and pain 2
• Ocular inflammation may develop before skin signs in SJS/TEN, so examine eyes carefully 1

If Tender Skin With Deep Tissue Involvement:

• The hard, wooden feel of subcutaneous tissue extending beyond the area of apparent skin involvement is pathognomonic for necrotizing fasciitis 1
• Clinical judgment is the most important element in diagnosis; CT or MRI may delay definitive diagnosis and treatment 1
• Surgical exploration remains the gold standard, where fascia appears swollen and dull gray with stringy areas of necrosis and a thin brownish exudate 1

Drug-Induced Skin Tenderness

• NSAIDs including ibuprofen can cause serious skin reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, and exfoliative dermatitis 4
• Patients should be advised to stop the drug immediately if they develop any type of rash or fever and contact their physician as soon as possible 4
• Warning signs include nausea, fatigue, lethargy, pruritus, jaundice, right upper quadrant tenderness and flu-like symptoms, which may indicate hepatotoxicity 4

Sensitive Skin Syndrome

• Sensitive skin is defined as a syndrome characterized by tightness, abnormal stinging, burning, tingling, pain and pruritus in response to stimuli that normally should not provoke such sensations 5
• These unpleasant sensations cannot be explained by any visible skin disease, and facial erythema may occur with other body areas involved 5
• Cosmetics are the main triggering factors according to patient reports, and environmental factors (cold, hot, dryness, pollution, wind, chemicals) commonly exacerbate symptoms 5

Atopic Dermatitis-Related Pain

• Skin pain in atopic dermatitis presents as soreness, discomfort, and tenderness that may reflect peripheral and central pain sensitization 6
• Recent studies suggest that skin pain presents as a neuropathic symptom independent from itch and the "itch-scratch cycle" 6
• The high prevalence of skin pain suggests it is not adequately addressed by current therapies and may be undertreated compared with other symptoms 6

Diagnostic Workup Algorithm

Step 1: Focused History

• Onset timing (acute vs. chronic), location (focal vs. diffuse, unilateral vs. bilateral), quality of pain (burning, stinging, tenderness), and aggravating factors (touch, temperature, cosmetics) 1, 7
• Recent medication exposures within 1-3 weeks, particularly antibiotics, anticonvulsants, NSAIDs, and allopurinol 1
• Associated symptoms including fever, malaise, upper respiratory symptoms, ocular inflammation, or mucosal involvement 1

Step 2: Physical Examination

• Distinguish primary lesions from secondary changes resulting from scratching 7
• Test for Nikolsky sign if epidermal necrolysis suspected 1
• Palpate for subcutaneous involvement (wooden feel, crepitus, extent beyond visible erythema) 1
• Examine all mucous membranes (eyes, mouth, nose, genitalia) for erosive and hemorrhagic mucositis 1

Step 3: Laboratory and Imaging

• If SJS/TEN suspected, immediate dermatology consultation takes precedence over laboratory testing 1
• If necrotizing fasciitis suspected, proceed directly to surgical exploration rather than delaying for imaging 1
• For chronic tender skin without clear etiology, consider CBC, chemistry profile, liver function tests, and thyroid function 3

Management Priorities

For Suspected SJS/TEN:

• Immediate cessation of all potentially causative medications 1
• Urgent dermatology consultation and transfer to burn unit or intensive care setting 1
• Supportive care with fluid resuscitation, wound care, and monitoring for complications 1

For Suspected Necrotizing Fasciitis:

• Emergency surgical debridement is the primary therapeutic modality 1
• Most patients should return to operating room 24-36 hours after first debridement and daily thereafter until no further need for debridement 1
• Broad-spectrum antibiotics covering anaerobes and aerobes, with average of 5 pathogens cultured from each wound 1

For Asteatotic Eczema/Xerosis:

• High-lipid content emollients at least twice daily to all affected areas 2, 3
• 1% hydrocortisone cream twice daily for 2 weeks 2, 3
• Avoid hot water bathing and harsh soaps 2
• If no improvement after 2 weeks, escalate to clobetasone butyrate (more potent topical steroid) 2
• Consider gabapentin 100-300 mg at bedtime if pruritus and tenderness persist after adequate topical therapy 3

For Herpes Zoster:

• Antiviral therapy initiated within 72 hours of rash onset 2
• Pain management with gabapentin or pregabalin for neuropathic component 2

Common Pitfalls to Avoid

• Do not dismiss prodromal pain before visible lesions appear, particularly in dermatomal distribution (herpes zoster) or with recent drug exposure (SJS/TEN) 1, 2
• Do not delay surgical exploration for imaging studies when necrotizing fasciitis is clinically suspected 1
• Do not use sedating antihistamines in elderly patients or those at risk for falls 2, 3
• Do not continue potentially causative medications when drug-induced skin reactions are suspected 4
• Do not attribute all skin tenderness to sensitive skin syndrome without excluding serious underlying conditions 5, 7

Referral Criteria

• Immediate dermatology referral for any suspicion of SJS/TEN or if diagnostic uncertainty exists 1, 2
• Immediate surgical consultation for suspected necrotizing fasciitis 1
• Dermatology referral if no improvement after 2-4 weeks of first-line therapy for presumed asteatotic eczema 2, 3
• Consider skin biopsy with direct immunofluorescence if bullous pemphigoid suspected (can present with tenderness alone before visible lesions in elderly patients) 3