03/08/2026
Case 7: The Rapidly Detaching Skin
Scenario:
You are asked to review a 28-year-old woman, Mrs. Eleanor Vance (a consistent volunteer!), in the emergency department. She has been admitted with an acute, worsening, painful, widespread red rash and multiple raw, weeping sores on her body. Crucially, she tells you her skin "just slides off" when she touches it. She has a high fever and is extremely distressed. She mentioned that she started a new antibiotic, co-trimoxazole, for a urine infection about 10 days ago.
History (HPC)
This is an acute medical emergency. Your history must be fast but meticulous, prioritizing identifying the potential trigger drug and distinguishing between SJS and TEN.
Onset & Progression: When did the first lesions appear? (Typically, this starts 7-21 days after drug exposure). Crucially: How fast is the skin changing? (TEN progresses in hours/days).
A "Dermatological Stroke": Advise the patient that this is considered an emergency.
Prodrome: Did she have a "flu-like" illness beforehand? (Often present: fever, sore throat, cough, malaise for 1-3 days before the rash).
Drug History (DH) (THE MOST CRITICAL POINT):
New Medications: Meticulously review ALL medications started in the last 2-4 weeks. (e.g., Co-trimoxazole, other antibiotics, Anticonvulsants like carbamazepine or lamotrigine, Allopurinol, NSAIDs).
Traditional or Herbal Remedies: Don't forget to ask!
Confirm: She confirmed starting co-trimoxazole 10 days ago.
Dermatological Symptoms:
Rash Character: Describe the initial rash. Was it painful or itchy? (Pain is often dominant).
Skin Detachment: Does the skin tear easily? (Nikolsky Sign is likely positive).
Mucosal Involvement: Ask about:
Mouth/Throat: Painful swallowing, ulcers, or sores.
Eyes: Painful, red, grittiness, or blurred vision. (Ocular involvement must be assessed early).
Genitals/Anal Area: Painful ulcers or sores.
Systemic Review: Check for severe complications:
Sepsis: High fever, rigors.
Respiratory: Shortness of breath, dry cough (potential tracheal involvement/pulmonary edema).
Gastrointestinal: Abdominal pain, bloody diarrhea (intestinal involvement).
Past Medical History (PMH):
Any history of other severe drug reactions (e.g., DRESS).
History of conditions that increase risk, such as HIV, active malignancy, or recent viral infections.
Examination
Your examination must be rapid and comprehensive, focusing on assessing the Body Surface Area (BSA) of detachment, mucosal involvement, and identifying signs of life-threatening complications.
1. General Inspection:
Does the patient look acutely unwell, toxic, or in severe distress? (Yes, often very toxic).
Vital Signs: Tachycardia, tachypnea, hypotension, hyper/hypothermia are indicators of severe systemic disease (Sepsis or fluid loss). Check and list the vital signs (e.g., "The patient is febrile (38.8°C), tachycardic (110 bpm), and tachypneic (24 rpm).")
2. Detailed Skin Examination (Assessing SJS vs. TEN):
Nikolsky Sign (CRUCIAL): Gently apply lateral pressure to an area of apparently normal skin. Does the top layer (epidermis) slide off easily, leaving a raw, moist dermis? (A positive Nikolsky sign indicates an intra-epidermal split and is diagnostic of SJS/TEN).
Body Surface Area (BSA) calculation (The Differentiator): You must estimate the percentage of total body surface area (TBSA) of detached and detachable (Nikolsky+) skin. (Use L&B chart, or remember the rule of nines/patient’s palm as 1%). This is fundamental for SJS vs. TEN.
SJS vs. TEN Classification: List the final calculation as well:
SJS (Stevens-Johnson Syndrome): 30% TBSA. (Mention the patient's estimated TBSA, e.g., "The estimated TBSA is 35%.").
Skin Morphology: Look for characteristic flat atypical target lesions (two zones: dark, purpuric center and outer red ring) or dusky/erythematous macular rash, followed by blistering and sheet-like detachment of the epidermis.
3. Inspection of Specific Areas:
Mucosal Membranes (Very important - almost universally present): Look for painful erosions, ulcers, and hemorrhagic crusting. You must look in:
Oral Mucosa: carefully check hard palate, gums, and tongue (Often severe involvement).
Conjunctiva (Eyes): Look for redness, discharge, ulcers, and signs of symblepharon (adhesion). Ocular assessment by an ophthalmologist is urgent.
Genitals/Anal Area: Look for painful ulcers and erosions.
4. Systemic Review:
Check for signs of sepsis, respiratory distress, and generalized edema. Assess the hydration status (SJS/TEN acts like a major burn with significant fluid loss).
What to Tell the Patient
Explain the Diagnosis: "Based on your rapidly detaching skin, positive Nikolsky sign, and history of starting co-trimoxazole, we are confident you have a condition called Toxic Epidermal Necrolysis (or TEN)." (Explain clearly, but don't cause unnecessary panic).
Explain the Condition: "This is a rare and very serious type of severe allergic reaction, usually triggered by a medication. That is why standard antibiotics won’t help. The reaction has caused extensive damage to the top layers of your skin, making them detach and slough off, much like a severe burn. We act as quickly as we can to stop the spread."
Explain the Multi-System Nature: "Crucially, because this condition also potentially affects other organs, such as your food pipe (esophagus), eyes, and lungs, we must do thorough testing, including checks on your breathing and blood pressure."
Confirming the Diagnosis: "To be absolutely sure and help us choose the best treatment, we will perform a skin biopsy (taking a small piece of skin). One is for a standard pathology to see the characteristic pattern, and the other is for standard tissue cultures to rule out other severe reactions like Necrotizing Fasciitis (which is a surgical emergency)."
Discuss Management:
"Crucially, the most important rule is that we must stop the trigger medication, co-trimoxazole, immediately and permanently." (This is a must-mention pearl).
"Management focuses on suppressing the immune system and supportive care. We start with potent immune-suppressing treatments like Corticosteroids (creams or tablets). Sometimes we use other powerful immunosuppressing drugs, depending on the severity and any underlying disease."
"Our primary goal is to stabilize you, prevent further spread, and maintain your function." (Explain the "dermatological burn" concept clearly).
Offer Support and Address Concerns: "I know this is terrifying, and the pain is excruciating. We prioritized your pain relief and we prioritized stabilize you first." (Acknowledge that this is a distressing condition for the patient).
Discussion
1. Diagnostic Features (Sub-epidermal split, etc.):
Clinical Diagnosis of Exclusion. This is vital. There is no one test.
Pathognomonic features: Positive Nikolsky sign, TBSA of detachment (SJS 30%), excruciating pain out of proportion to appearance.
Associations: Strong genetic predisposition with certain medications (e.g., HLA-B15:02 with carbamazepine; HLA-B58:01 with allopurinol), other factors like HIV.
2. Differential Diagnosis:
SSS/TEN vs. SJS: (Mention the key differentiator, e.g., "The key differentiator is the percentage of body surface area involved, with SJS being 30%.").
Necrotizing Fasciitis: This is a surgical emergency. TEN involves the dermis and epidermis, not the underlying fascia.
AGEP: Characterized by many smaller pustules.
SSS (Staphylococcal Scalded Skin Syndrome): Usually in children, Nikolsky positive, but a more superficial split with different histological pattern, associated with a preceding focal staph infection. Cultures are vital.
3. Investigations:
Diagnosis is Clinical.
Skin Biopsy: Routine H&E from an active border to differentiate between intra-epidermal (e.g., pemphigus) and sub-epidermal split.
Cultures: Critical to exclude unusual infections and other severe reactions.
Blood Test: SCORTEN for predicting prognosis. (Mention the patient's SCORTEN calculation if specified).
4. Management Principles:
Golden Rule: STOP THE TRIGGER MEDICATION. (Trauma triggers rapid expansion – pathergy).
Patient Education & Support: Explain it is autoimmune, not an infection. Prioritize pain relief.
Initial Therapy: Powerful Corticosteroids (creams, logic local injection, or systemic prednisolone). Sometimes immunosuppressants like Cyclosporine are used first-line for faster action.
Refractory/Systemic: Use disease-modifying agents (Methotrexate, Azathioprine, Mycophenolate Mofetil).
Biologics: Anti-TNF agents (e.g., adalimumab, infliximab) can be effective, particularly if associated with IBD.
End of Case with Pearls
PACES Pearls for Case 7:
Dermatological Burn: Manage SJS/TEN like a major burn: ICU/burn unit admission, careful fluid management, and prevention of infection.
STOP THE DRUG NOW: Immediately and permanently identify and stop the potential trigger drug.
BSA Differentiates SJS vs. TEN: Meticulously calculate TBSA to determine classification (SJS 30%).
Nikolsky Sign is positive: This indicates an intra-epidermal split and is diagnostic.
Look BEYOND THE FACE: Check the mouth, eyes, and ge****ls for mucosal involvement.
COMPLETE MULTI-SYSTEM EXAM: TEN is not just a skin/joint disease. Mention checking the blood pressure (renal/HTN), auscultating (serositis), and doing a CNS overview if directed or time permits.
Diagnostic Pathway: Biopsy essential but requires expert selection of site. Biopsy risk is vital to check first.
Management Ladder: Primary therapy is powerful corticosteroids (topical or systemic) or cyclosporine. Antibiotics don't help.
Prognostic Tools (SCORTEN): Be prepared to mention this validated scoring system for predicting mortality.
Auspitz vs. Koebner: Don't confuse the two! Auspitz is pinpoint bleeding from picking at a plaque; Koebner is new lesions in new areas of trauma.
Pathergy vs. Nikolsky: Know the difference! Pathergy = rapid spread of wound following trauma/debridement. Nikolsky = skin slides off with lateral pressure.