Dermatological emergencies

Meet the patient

A 34-year-old woman is two weeks into a course of carbamazepine when she arrives febrile, with painful skin, a crusted bloody mouth, and sheets of epidermis sliding off her back at the lightest touch. The Nikolsky sign is positive and the conjunctivae are weeping.^[10]

Two questions now decide whether she lives without blindness: what is this? and what do I do in the next fifteen minutes? Everything below exists to answer those two questions before the biopsy comes back. This is TEN until proven otherwise — STOP the drug, call ICU and ophthalmology, and calculate SCORTEN.^[1][9]

The unifying concept — acute skin failure

Think of the skin as an organ that can fail, exactly like the kidney or the lung. When it fails across a large surface area the consequences are identical to a burn: fluid and electrolyte loss, protein loss, hypothermia, sepsis, and high-output cardiac failure.^[1][2]

The examiner's distinction that earns marks is between a bad rash (uncomfortable but self-limiting) and a skin emergency (death or permanent disability within hours). The whole topic is the bedside skill of telling them apart on inspection.^[1]

Four mechanisms, one first response

The conditions group into four mechanisms — but the first response is always the same. ^[1]

^[1]

The first response never waits for a biopsy: ABCDE, stop every drug started in the last eight weeks, fluid resuscitate, give IV antibiotics for purpura with fever, call surgery for necrosis, protect the airway for angioedema. The dermatologist is called early but does not own the first hour.^[1]

The two governing principles

First: a febrile patient with a rash and systemic upset is assumed to have a dermatological emergency until proven otherwise. The cost of missing meningococcaemia or TEN is death; the cost of over-calling a viral exanthem is a brief admission.^[1]

Second: recognition and resuscitation precede diagnosis. The immediate actions are taken on the clinical pattern alone, before biopsy, cultures, or specialist review confirm the specific entity. Diagnose on the move; the patient is dying while you deliberate.^[1][2]

Epidemiology & Risk Factors

The high-risk drugs, host factors, and mortality figures are exactly what examiners probe. SJS, TEN, and SJS/TEN overlap are rare, severe cutaneous adverse reactions usually triggered by medications. Hospital mortality of toxic epidermal necrolysis is about 30 percent.^[10][9]

DRESS, in the prospective RegiSCAR series, yielded 117 probable or definite cases from 201 potential enrolments; two patients died in the acute phase, and mortality was lower than prior publications suggested. Awad's systematic review of 151 probable or definite cases reported 13 deaths (9 percent), with a median rash onset of 24 days and facial oedema in 44 percent.^[6][7]

^{[9] [6] [7] [13] [26] [27]}

Staphylococcal scalded skin syndrome is a paediatric emergency caused by staphylococcal exfoliative toxin cleaving desmoglein-1; mucosa is spared. Sourced child and adult percentage mortalities are not in the fetched abstracts used on this page — teach the mechanism and the antibiotic, not a memorised fatality band.^[5]

Necrotising fasciitis is life-threatening; delay to diagnosis and surgical management is associated with increased mortality. Do not quote an unsourced 20 to 40 percent band from this page.^[11]

Erythrodermic psoriasis presents with scaling and erythema affecting more than 75 percent of body surface area plus systemic features (lymphadenopathy, fever, dehydration, electrolyte disturbance, tachycardia), making it potentially life-threatening.^[8]

The risk factors for a severe drug reaction that this page can source are the culprit classes themselves. In RegiSCAR DRESS, antiepileptic drugs were involved in 35 percent, allopurinol in 18 percent, antimicrobial sulphonamides and dapsone in 12 percent, and other antibiotics in 11 percent. Named HLA–drug pairs are not recited from the abstracts fetched for this page.^[6]

Pathophysiology — name the molecule, not "allergy"

The examiner rewards the candidate who names the molecular target rather than says "it is an allergic reaction." Each emergency has a distinct, examinable mechanism.^[1]

Stevens-Johnson syndrome and TEN are drug-induced, full-thickness keratinocyte apoptosis. The dominant effector is granulysin, a cytotoxic molecule released by drug-specific CD8-positive T cells and natural killer cells; Fas-Fas ligand, perforin/granzyme, and tumour necrosis factor contribute. The result is confluent epidermal necrosis with a subepidermal split, leaving a denuded, bleeding dermis analogous to a thermal burn.^[10]

SSSS is toxin-mediated, not T-cell-mediated. Phage group II Staphylococcus aureus at a distant focus (conjunctivitis, otitis, a wound) produces exfoliative toxin A or B, which circulates haematogenously and cleaves the extracellular domain of desmoglein-1 in the stratum granulosum. The split is high and superficial — only the uppermost epidermis separates.^[4]

Mucosae are spared (Leung: absence of mucosal involvement is part of the clinical diagnosis) — and that is the cardinal distinction from SJS/TEN.^[5]

DRESS/DIHS is a systemic drug hypersensitivity. Sourced latency is a median 22 days (IQR 17 to 31) in RegiSCAR and a median cutaneous onset of 24 days in Awad. Recite those denominators, not an unsourced 2-to-8-week band or an HHV-6 mechanism from this page.^[6][7]

AGEP is the fastest-onset severe cutaneous drug reaction. Drug-specific CD4-positive T cells home to the epidermis and release IL-8 (CXCL8), a potent neutrophil chemoattractant. Neutrophils fill the subcorneal space as sterile, culture-negative pustules. The lack of deep necrosis explains the low mortality and rapid resolution once the drug is withdrawn.^[2]

Erythroderma is a failure of epidermal turnover and barrier function. Massive cutaneous vasodilation over a large surface area produces continuous insensible loss of water, electrolytes, and protein; heat loss causes shivering and hypothermia; and the persistent vasodilation generates a hyperdynamic circulation that can precipitate high-output cardiac failure in the elderly.^[8]

Necrotising fasciitis is a spreading infection of subcutaneous tissue and deep fascia that initially spares muscle and overlying skin. Three microbiological types: Type I polymicrobial (anaerobes plus Gram-negatives, after surgery or in diabetics); Type II monomicrobial Group A streptococcal after minor trauma; and Type III marine (Vibrio vulnificus, Aeromonas) after seawater exposure. Tissue destruction is driven by direct invasion plus exotoxins that produce a toxic-shock phenotype.^[11]

Purpura fulminans is DIC localised to the dermal microvasculature. Microthrombi occlude dermal capillaries and venules, producing haemorrhagic infarction in a characteristic retiform (net-like, stellate) pattern that progresses to full-thickness necrosis. The three settings are neonatal homozygous protein C deficiency, acute infectious (overwhelming meningococcaemia), and idiopathic post-infectious with acquired protein S deficiency.^[13]

Hereditary angioedema is an autosomal dominant C1-inhibitor disorder affecting 1 in 50,000 people worldwide. Three main types exist; most cases are type I (C1-INH deficiency). Type I and type II result from SERPING1 mutation. Betschel frames contemporary care as newer targeted therapies for acute attacks and long-term prophylaxis, developed from HAE pathophysiology — not as generic anaphylaxis drugs.^[16][15]

Clinical Presentation — recognise on inspection

Erythroderma (exfoliative dermatitis)

The sourced definition for erythrodermic psoriasis is scaling and erythema affecting more than 75 percent of body surface area, associated with systemic symptoms such as lymphadenopathy, arthralgia, fever, fatigue, dehydration, electrolyte disturbance, and tachycardia.^[8]

Lymphadenopathy (dermopathic) is common, and ectropion and alopecia may accompany chronic disease. The acute danger signs are tachycardia, hypotension, oliguria (hypovolaemia), confusion (hypothermia or sepsis), and respiratory distress from high-output cardiac failure.^[8]

Stevens-Johnson syndrome / toxic epidermal necrolysis

A flu-like prodrome is followed by a macular, targetoid, or purpuric rash that coalesces and then detaches. Classification is by percentage of detached epidermis.^[10]

^{[23] [10]}

Bastuji-Garin 1993 also lists TEN without spots: detachment above 10 percent BSA without the spotted macule pattern. Mucosal involvement is part of the SJS/TEN clinical picture and is the practical bedside fork from SSSS (Leung: mucosa spared). Positive Nikolsky sign is described in SSSS.^[23][5][10]

DRESS / DIHS

The presentation is fever, rash, and internal organ involvement after a delayed drug latency. RegiSCAR: median interval after drug intake 22 days (IQR 17 to 31). Awad: median cutaneous onset 24 days; facial oedema in 67 of 151 cases (44 percent). The rash is typically maculopapular.^[6][7]

In RegiSCAR probable or definite DRESS the main features besides exanthem were eosinophilia (95 percent), visceral involvement (91 percent), high fever (90 percent), atypical lymphocytes (67 percent), mild mucosal involvement (56 percent) and lymphadenopathy (54 percent). Two patients died in the acute phase.^[6]

AGEP (Acute Generalised Exanthematous Pustulosis)

AGEP typically presents with at least dozens of non-follicular sterile pustules on a diffuse, oedematous erythema, predominantly in the folds and/or on the face. Fever and elevated blood neutrophils are common. Onset is acute, most often following drug intake; viral infections can also trigger the disease. Pustules resolve spontaneously in less than 15 days.^[25]

EuroSCAR (97 validated community cases) found strongly associated drugs including pristinamycin, ampicillin/amoxicillin, quinolones, (hydroxy)chloroquine, anti-infective sulphonamides, terbinafine and diltiazem. Infections played no prominent role, and there was no evidence that AGEP is a variant of pustular psoriasis. Do not quote an unsourced under-4-day or under-5-percent-mortality band from this page.^[28]

Staphylococcal scalded skin syndrome

In an infant or child under 5, a focal staphylococcal infection is followed by systemic spread of exfoliative toxin. The sequence: diffuse tender erythema, then large flaccid bullae that rupture easily, then sheet-like peeling leaving a moist, glistening, scalded surface.^[4]

The Nikolsky sign is positive. The mucosae are spared — oral, conjunctival, and genital — because desmoglein-3 maintains mucosal integrity. That single feature is the bedside fork from SJS/TEN.^[5]

Necrotising fasciitis

The red flag is pain grossly disproportionate to the visible skin signs. Fernando's meta-analysis: pooled sensitivity/specificity for fever 46.0/77.0 percent, haemorrhagic bullae 25.2/95.8 percent, and hypotension 21.0/97.7 percent — absence of any one sign does not rule NSTI out. CT sensitivity 88.5 percent and specificity 93.3 percent (plain radiography 48.9/94.0 percent); CT is superior to plain films but still does not replace theatre in a toxic patient.^[11][2]

Crepitus may be present in gas-forming infection. Systemically the patient develops high fever, tachycardia, hypotension, altered mental state, and multi-organ failure — a toxic-shock picture out of proportion to the visible lesion.^[11]

Purpura fulminans / meningococcaemia

The rash begins as small petechiae and rapidly coalesces into retiform (net-like, geographic) purpura with sharply demarcated, dusky edges that progress to frank cutaneous necrosis, especially on the extremities.^[13]

This is accompanied by fever, shock, and signs of DIC. In a patient-level synthesis of 190 adults, Neisseria meningitidis and Streptococcus pneumoniae each caused 32 percent of cases; surgical debridement was reported in 71 of 190 (38 percent) and amputations in 154 of 190 (81 percent). The rash with fever is the trigger to treat now, not to investigate.^[13]

Generalised pustular psoriasis (von Zumbusch)

An explosive eruption of widespread, sterile, pinpoint pustules on intensely erythematous skin, with high fever, rigors, malaise, and marked leukocytosis. The patient is erythrodermic and unwell; pustules coalesce into lakes of pus and then desquamate.^[14]

There may be a history of chronic plaque psoriasis. Precipitants include systemic corticosteroid withdrawal, infections, pregnancy (impetigo herpetiformis), hypocalcaemia, and irritating topical therapy.^[14]

Angioedema / anaphylaxis

Rapidly progressive, non-pitting swelling of the deep dermis and subcutis, most dangerous at the lips, tongue, floor of mouth, and larynx — stridor, drooling, respiratory distress. Histamine-mediated angioedema (allergic/anaphylaxis) comes with urticaria, itch, bronchospasm, hypotension.^[15]

Bradykinin-mediated angioedema (hereditary, acquired, ACE-inhibitor) causes episodic swelling without urticaria, pruritus, or hypotension, and tends to be slower but more refractory. Recurrent, unexplained, non-urticarial swellings are the clue to HAE.^[16]

Toxic shock syndrome

TSS is a toxin-mediated superantigen emergency, not a direct skin infection. Menstrual TSS (tampon-associated, TSST-1) and non-menstrual TSS (post-surgical, post-burn) present with abrupt high fever, hypotension, a diffuse sunburn-like macular erythroderma, conjunctival and mucosal hyperaemia, strawberry tongue, and multi-organ failure. Desquamation of palms and soles follows in 1 to 2 weeks.^[1]

Streptococcal toxic shock (Group A strep, often with necrotising fasciitis) is clinically similar but bacteraemic and rapidly progressive. Management is aggressive fluid resuscitation, source control, IV antibiotics (clindamycin to suppress toxin), and IVIG for severe cases.^[1]

Differential Diagnosis — four discriminating questions

The differentials cluster around four high-yield questions: is the mucosa involved? What is the cleavage plane? What is the latency from drug to rash? Is there systemic toxicity?^[1]

The single most tested distinction is SSSS versus SJS/TEN — and the discriminator line is the mucosa:^[4]

^{[4] [10]}

For the drug-reaction latency question, the discriminator is time:^[7]

^[2]

For a rapidly spreading painful red leg, the discriminator for necrotising fasciitis is the combination of severe pain out of proportion, rapid progression, and systemic toxicity — against cellulitis (slow, well-demarcated), erysipelas (sharply raised), gas gangrene (clostridial, crepitus, bronze), and calciphylaxis (renal failure, painful necrotic ulcers with livedoid edges).^[11]

For erythroderma, the cause categories fall in roughly equal thirds: pre-existing dermatosis (psoriasis, eczema, pityriasis rubra pilaris), drug reaction, and underlying disease (CTCL/Sézary, pemphigus foliaceus, ichthyosiform), with idiopathic the remainder.^[1]

Clinical & Bedside Assessment

Every suspected dermatological emergency is assessed first by ABCDE, then by a focused skin examination. The airway is the immediate threat in angioedema with laryngeal involvement and in SJS/TEN with tracheobronchial sloughing.^[1]

Breathing may be compromised by bronchospasm (anaphylaxis) or the hyperdynamic pulmonary oedema of erythroderma. Circulation is threatened by hypovolaemia (erythroderma, SSSS, SJS/TEN all lose fluid through denuded skin) and by distributive shock (necrotising fasciitis, purpura fulminans). Disability reflects hypothermia or septic encephalopathy. Exposure is the dermatological examination itself.^[1]

^[1]

In necrotising fasciitis, feel for the "hardwood" induration — loss of normal subcutaneous softness, a woody-hard tissue that distinguishes it from cellulitis. Look for a portal of entry (trauma, surgical wound, IV cannula, fissure) and palpate for crepitus.^[11] Bedside ultrasound can add confidence here — a thickened, fuzzy deep fascia with fluid and subcutaneous gas supports necrotising fasciitis, and high-frequency sonography helps gauge bulla depth in the blistering eruptions — but it never replaces the theatre decision in a toxic patient.^[3]

In suspected DRESS, examine the face for oedema, palpate all lymph node groups, and feel for hepatomegaly. In suspected HAE, ask about family history, recurrent unexplained abdominal pain (bowel-wall oedema), and episodes triggered by dental work or trauma; measure the swelling velocity.^[1]

Investigations — support, never delay

Investigations support but never delay treatment in the time-critical conditions. The named scores are reproduced verbatim because they are the examinable material.^[1]

SCORTEN (severity of illness for TEN)

Seven independent risk factors constitute SCORTEN. Each scores one point; the odds ratio per point is 3.45 (CI 2.26 to 5.25). The score was developed on 165 patients and validated on 75. The abstract does not prescribe a 24-hour / 72-hour calculation schedule, and it does not publish the textbook 3 / 12 / 35 / 58 / 90 percent bands — do not recite those from this page.^[9]

^{[9] [9]}

RegiSCAR criteria (DRESS/DIHS diagnosis)

RegiSCAR used a standardized scoring system and validated 117 of 201 enrolled cases as probable or definite DRESS. Recite the observed feature frequencies from that prospective series, not an unsourced point table: eosinophilia 95 percent, visceral involvement 91 percent, high fever 90 percent, atypical lymphocytes 67 percent, mild mucosal involvement 56 percent, lymphadenopathy 54 percent.^[6]

LRINEC score (laboratory risk indicator for necrotising fasciitis)

Wong constructed LRINEC from six admission laboratories: total white cell count, haemoglobin, sodium, glucose, serum creatinine, and C-reactive protein. A score of 6 or more should prompt careful evaluation (Wong cutoff PPV 92.0 percent, NPV 96.0 percent in the derivation/validation cohorts). Fernando: LRINEC of 6 or more has sensitivity 68.2 percent and specificity 84.8 percent; of 8 or more, 40.8 / 94.9 percent — poor sensitivity, and it must not be used to rule NSTI out. Tarricone (extremity disease): sensitivity 49.39 percent, specificity 83.17 percent at the same threshold. Point-value tables for each laboratory band are not in the fetched abstracts and are not reproduced here.^[24][11][12]

Biopsy and laboratory

In SSSS, a skin biopsy with frozen section shows a superficial intraepidermal split at the stratum granulosum — no necrosis, no inflammation, no organisms. That distinguishes it from SJS/TEN (full-thickness necrosis) and bullous impetigo (subcorneal pustules with organisms).^[4]

In SJS/TEN, biopsy shows full-thickness epidermal necrosis with a sparse infiltrate. A shave or punch biopsy is performed but must not delay treatment.^[1]

In DRESS, the laboratory phenotype that this page can source is the RegiSCAR pattern: eosinophilia, atypical lymphocytes, visceral involvement (especially hepatitis), and lymphadenopathy. Awad: systemic corticosteroids were the mainstay of DRESS-specific treatment. Do not recite unsourced ULN cut-offs or serial HHV-6 PCR schedules from this page.^[6][7]

In necrotising fasciitis, the operative finding is the investigation: foul-smelling "dishwater" fluid, grey necrotic fascia that separates easily (positive "finger test"), thrombosis of perforating vessels, and lack of bleeding from the fascia. Tissue and deep wound cultures (not superficial swabs) guide therapy. Imaging is reserved for the haemodynamically stable patient with an ambiguous presentation — in a classic toxic patient, theatre is the investigation. Fernando: high clinical suspicion warrants early surgical consultation without waiting for test results.^[11]

In purpura fulminans, send coagulation (PT, APTT, fibrinogen, D-dimer), full blood count with blood film (schistocytes suggest microangiopathy), blood cultures (meningococcus, pneumococcus), and protein C, protein S, and antithrombin drawn before transfusion. Biopsy shows dermal microvascular thrombosis with full-thickness infarction and scant inflammation — the paucity of inflammation distinguishes it from leukocytoclastic vasculitis.^[13]

Rapid Assessment Algorithm

ABCDE and vitals come first; the skin examination then drives the immediate action set.^[1]

^[1]

Management — the resuscitation phase

The resuscitation phase is identical in principle across all dermatological emergencies — it is what the patient is dying of while you make the diagnosis.^[1]

A — Airway. Angioedema with stridor, drooling, or tongue swelling needs early anaesthetic and ENT involvement; prepare for awake fibre-optic intubation or surgical airway. In SJS/TEN with tracheobronchial involvement, anticipate a difficult, bleeding airway.^[1]

B — Breathing. High-flow oxygen; bronchodilators for bronchospasm (anaphylaxis); monitor for pulmonary oedema in erythroderma.^[1]

C — Circulation. Two large-bore IV cannulae. In erythroderma, SSSS, and SJS/TEN, fluid and electrolyte losses through failed skin are substantial — resuscitate with IV crystalloid; children with SSSS who cannot maintain oral intake need fluid resuscitation. In necrotising fasciitis, initiate immediate surgical debridement and antibiotic therapy, with aggressive supportive care for septic shock. In anaphylaxis, give IM epinephrine 0.01 mg/kg (1:1000; maximum single dose 0.5 mg), repeated after 5 to 10 minutes if needed; there are no absolute contraindications.^[18][17]

D — Disability. Correct hypothermia (warmed fluids, forced-air warming, ambient temperature up); glucose; treat seizures.^[1]

E — Exposure and Environment. Fully expose the skin (then cover to preserve heat), examine, and document BSA and detachment. Stop all new drugs started within 8 weeks. Decubitus care, eye care (ophthalmology within hours for SJS/TEN), and catheterisation (SJS/TEN with urethral involvement) are part of resuscitation, not an afterthought.^[1]

Management — Definitive and Stepwise

SJS / TEN

The bundle is supportive first, immunomodulation second — and STOP the drug is the one intervention everyone agrees on.^[1]

^[10]

The classic trap: do not delay tertiary-level supportive care (stop the culprit, fluids, wound and eye care) while debating immunomodulation. Cochrane: etanercept may reduce mortality versus corticosteroids; other comparisons are very-low-certainty.^[10]

DRESS / DIHS

Stop the drug and start systemic corticosteroids — Awad: systemic corticosteroids were the mainstay after culprit cessation; Ak: some cases progress despite 1 mg/kg/day of prednisolone or intravenous methylprednisolone equivalent, and pulse methylprednisolone 250 mg/day for 3 days (or plasmapheresis) was used in refractory organ-threatening disease.^[7][20]

Staphylococcal scalded skin syndrome

Anti-staphylococcal antibiotic, fluids, and bland emollients — Gray supports a less-is-more work-up and skin-care approach.^[4][5]

^{[4] [5]}

Gray: clindamycin does not improve outcomes; beta-lactam antibiotics are preferred first-line. Fluid resuscitation for children unable to maintain oral intake; bland emollients for skin care.^[4]

Erythroderma

Admit and manage like a burn: fluids, temperature, emollients, sepsis watch, thromboprophylaxis, and treat the cause.^[8]

Fluid and electrolyte management is central — IV crystalloid to replace ongoing losses, with daily weighing and urine output monitoring. Replace ongoing losses with IV crystalloid and monitor electrolytes. Apply emollients frequently. Mastorino frames erythrodermic psoriasis as potentially life-threatening because of dehydration, electrolyte disturbance and tachycardia — treat those physiology problems, and do not quote an unsourced ambient-temperature target from this page.^[8]

Necrotising fasciitis

This is a surgical emergency. The definitive treatment is emergency surgical debridement of all necrotic tissue down to bleeding, healthy muscle and fascia, with a low threshold for re-look debridement at 24 to 48 hours.^[11]

Antibiotics are started immediately with emergency surgical debridement — antibiotic therapy and debridement are initiated together. Given the poor sensitivity of clinical scores and imaging in early disease, a high clinical suspicion warrants early surgical consultation without waiting for test results.^[2][11]

Purpura fulminans

Treat the underlying cause aggressively. Purpura fulminans presents as cutaneous manifestations complicating septic shock with limb ischaemia, and surgical intervention is necessary to control the pathological cascade; in a systematic review of 190 adults, Neisseria meningitidis and Streptococcus pneumoniae each caused about a third of cases.^[13]

Klifto: in a state of septic shock complicated by limb ischaemia, surgical interventions are necessary. Debridement 71/190 (38 percent); amputations 154/190 (81 percent). Specific clotting-factor replacement protocols are not recited from the fetched abstract.^[13]

Generalised pustular psoriasis (von Zumbusch)

Admit as a systemic inflammatory emergency. Hsu: use of acitretin appeared higher and more effective among East Asians compared with other populations. Do not recite unsourced US/EU-approval or ciclosporin-onset claims from this page.^[22]

Angioedema / anaphylaxis

The critical decision is whether the swelling is histamine- or bradykinin-mediated — because the treatments are entirely different.^[15]

^{[15] [16] [18]}

The classic trap: histaminergic anaphylaxis gets intramuscular epinephrine first-line. Hereditary angioedema is a C1-INH disorder treated with targeted therapies for acute attacks and long-term prophylaxis — do not treat it as generic anaphylaxis.^[18][16][15]

Calciphylaxis (calcific uraemic arteriolopathy)

Included as the vascular dermatological emergency of the dialysis patient: painful, stellate-livedoid, necrotic skin ulcers over areas of subcutaneous fat. Kodumudi: 1-year mortality of up to 50 percent; dialysis incidence 0.04 to 4 percent. Glennon (268 patients): 1-year disease-specific mortality 28.88 percent, lower than historic 45 to 80 percent.^[26][27]

Kodumudi: pain treatment should be multimodal and include wound care as well as modification of risk factors. Targeted disease-modifying regimens are the subject of ongoing trials and are not recited as proven cures from this page.^[26]

Specific Subtypes & Scenarios

Erythroderma by aetiology. The dermatosis group (psoriasis, eczema, pityriasis rubra pilaris) is treated by intensifying the underlying therapy. The drug group withdraws the culprit (sulphonamides, antiepileptics, gold, penicillin, allopurinol). The malignancy group — above all cutaneous T-cell lymphoma (Sézary syndrome) — needs systemic oncology therapy. The idiopathic group needs long-term surveillance, because a lymphoma may declare itself months to years later.^[8]

Necrotising fasciitis by type. Type I polymicrobial occurs after surgery, in diabetics, and in the perineum (Fournier gangrene). Type II monomicrobial Group A streptococcal follows minor trauma, varicella, or IV drug use, often with streptococcal toxic shock. Type III marine (Vibrio vulnificus, Aeromonas) follows seawater or raw seafood exposure, especially in liver disease, and runs a fulminant course.^[1]

Angioedema by mechanism. HAE is autosomal dominant and affects 1 in 50,000; most cases are type I (C1-INH deficiency). Type I and type II both come from SERPING1 mutation. Do not recite an 85/15 percent split from this page. Contemporary treatment is targeted therapy for acute attacks and long-term prophylaxis rather than generic anaphylaxis drugs.^[16][15]

Purpura fulminans by setting. Neonatal purpura fulminans is homozygous protein C deficiency presenting with DIC and skin necrosis in the first days of life; treat with protein C concentrate and FFP. Acute infectious purpura fulminans complicates overwhelming meningococcaemia, pneumococcaemia, or varicella. Idiopathic post-infectious purpura fulminans follows a viral illness with autoantibodies to protein S.^[13]

Pemphigus vulgaris as a dermatological emergency. A life-threatening autoimmune blistering disease producing blisters and erosions of the mucous membranes and skin — before immunosuppressive treatment it was almost always fatal. Treatment now includes rituximab, approved as first-line therapy for moderate-to-severe pemphigus vulgaris in Europe and the United States, alongside immunosuppressive therapy and supportive wound care.^[21]

Kawasaki disease (mucocutaneous lymph node syndrome). A paediatric vasculitis emergency because untreated coronary artery aneurysms develop in about 25 percent. McCrindle (AHA 2017) notes that classic clinical criteria may be incomplete and supplies a supplemental diagnostic algorithm; this page does not recopy an unsourced 5-day plus 4-of-5 table. IVIG is the mainstay of initial treatment.^[29]

Treatment is IVIG 2 g/kg infused over 10 to 12 hours together with aspirin — the standard of treatment for preventing coronary artery aneurysms in Kawasaki disease.^[19]

Complications & Pitfalls

Erythroderma causes hypothermia, hypovolaemia, hypoalbuminaemia, high-output cardiac failure, hypothermia-induced coagulopathy, sepsis from skin organisms, and venous thromboembolism (a recognised hypercoagulable state).^[8]

SJS/TEN causes corneal adhesions, symblepharon, and blindness (the leading cause of long-term disability); oesophageal, urethral, vaginal, and bronchial strictures; cutaneous scarring and dyspigmentation; nail dystrophy and loss; and death from sepsis or multi-organ failure. Early and daily ophthalmology is non-negotiable.^[1]

SSSS is managed with an intravenous anti-staphylococcal beta-lactam, fluids if oral intake fails, and bland emollients. The classic error is treating it as SJS/TEN.^[5][4]

Necrotising fasciitis causes limb loss, multi-organ failure, and death. The classic errors are sending the patient for CT/MRI and waiting for the report, attributing severe pain to a "bad cellulitis," and inadequate initial debridement.^[11]

DRESS mortality in Awad was 13 of 151 (9 percent); allopurinol was associated with 23 percent of deaths (3 cases). RegiSCAR recorded 2 acute-phase deaths in 117 probable or definite cases.^[7][6]

Prognosis & Disposition

Prognosis is captured by sourced denominators, not textbook bands. TEN hospital mortality is about 30 percent; SCORTEN odds ratio 3.45 per point (derivation 165, validation 75). DRESS: 2 acute deaths in 117 RegiSCAR probable/definite cases; Awad 13 of 151 (9 percent). Adult purpura fulminans: amputations 154/190 (81 percent); debridement 71/190 (38 percent). Calciphylaxis: Kodumudi up to 50 percent at one year; Glennon disease-specific 28.88 percent (historic 45 to 80 percent). SSSS child/adult percentage mortalities and a 20 to 40 percent necrotising-fasciitis band are not in the fetched abstracts used here.^{[9][6][7][13][26][27][11]}

Disposition. Cochrane frames SJS/TEN as needing tertiary-level supportive care. Usatine: most cases of SJS and TEN are drug induced; the causative drug should be discontinued immediately, and the patient should be hospitalized for supportive care. Necrotising fasciitis needs immediate surgical debridement. Purpura with fever needs immediate parenteral benzylpenicillin or a third-generation cephalosporin.^{[10][2][11][30]}

Special Populations

Paediatric. SSSS: intravenous anti-staphylococcal beta-lactam (nafcillin, oxacillin, or flucloxacillin), mucosa spared. Kawasaki: untreated coronary aneurysms in about 25 percent; IVIG 2 g/kg over 10 to 12 hours with aspirin. Anaphylaxis: IM epinephrine 0.01 mg/kg, maximum single dose 0.5 mg, repeat after 5 to 10 minutes. Necrotising fasciitis: immediate debridement plus antibiotics; do not wait for LRINEC.^{[5][29][19][18][11]}

Pregnancy, elderly, dialysis, anticoagulation. Load-bearing drug-safety lists for pregnancy and renal dose tables are not in the abstracts fetched for this page and are not recited here. The sourced dialysis emergency on this page is calciphylaxis (Kodumudi up to 50 percent 1-year mortality; Glennon 28.88 percent disease-specific).^[26][27]

Evidence, Guidelines & Regional Differences

Usatine: Rocky Mountain spotted fever has an overall mortality rate of 5 to 10 percent; necrotising fasciitis presents with pain out of proportion and needs immediate surgical debridement plus antibiotics.^[2]

The 2022 Cochrane review: when compared to corticosteroids, etanercept may result in mortality reduction. For corticosteroids versus no corticosteroids, IVIG versus no IVIG, and ciclosporin versus IVIG, certainty of evidence for disease-specific mortality is very low. Adequately powered multicentre trials are still needed.^[10]

^[9]

Cochrane still quotes the methylprednisolone 4 mg/kg/day comparison against no corticosteroids as uncertain for disease-specific mortality (very-low-certainty evidence).^[10]

The RegiSCAR DRESS series sourced the culprit mix used on this page: antiepileptics 35 percent, allopurinol 18 percent, antimicrobial sulphonamides and dapsone 12 percent, other antibiotics 11 percent. Named HLA–drug pairs and mandated genetic screening are not in the abstracts fetched for this page and are not recited here.^[6]

^{[10] [15] [17] [10] [15] [17] [17] [15] [30] [5] [22] [10]}

Controversies. Cochrane leaves most SJS/TEN systemic comparisons at very-low-certainty; LRINEC has poor sensitivity and must not rule NSTI out; calciphylaxis disease-modifying drugs remain trial territory on this page.^[10][11][26]

The mantra and the memory devices

The mantra for every dermatological emergency: ABCDE, STOP the drug, resuscitate, then name the score.^[1]

^{[6] [20] [13] [25] [22] [5] [1]}

Ward-round test

A 3-year-old has diffuse erythema, skin tenderness, and sheet-like peeling; the mouth is normal. Diagnosis and first treatment?ShowHide

Staphylococcal scalded skin syndrome. The spared mucosa, superficial split, and age make it toxin-mediated, not SJS/TEN. First treatment is an intravenous anti-staphylococcal beta-lactam (nafcillin, oxacillin, or flucloxacillin), fluids, bland emollients, and analgesia — Gray's review supports a less-is-more work-up and skin-care approach. ^[5][4]

A febrile patient on day 18 of nevirapine has a morbilliform rash, facial oedema, and ALT 600. Diagnosis and the trap?ShowHide

DRESS/DIHS. Facial oedema (44 percent of cases), eosinophilia, and hepatitis on a maculopapular rash with a median 24-day onset are the fingerprint. Stop the drug; Awad: systemic corticosteroids are the mainstay. Ak: some cases progress despite 1 mg/kg/day and then used pulse methylprednisolone 250 mg/day for 3 days or plasmapheresis. ^[7][20]

Recurrent lip and tongue swelling with no urticaria, not responding to adrenaline. What is it and what works?ShowHide

Hereditary angioedema — autosomal dominant, with C1-INH deficiency (type I) or dysfunction (type II); recurrent episodic swelling without urticaria is the clue, and attacks need targeted therapy (IV C1-INH concentrate or a bradykinin receptor antagonist) rather than anaphylaxis medications. ^[15][16]

A diabetic has a red, painful leg with pain out of proportion to the redness, and a LRINEC score of 4. What now?ShowHide

Necrotising fasciitis remains on the table — a low LRINEC does not exclude it. Clinical judgement overrides the score. Start antibiotic therapy and take the patient to theatre for emergency debridement; do not delay for imaging. ^[11][2]

References30ShowHide

1. [1]Gruver JR, Kirkorian AY. Pediatric dermatologic emergencies Curr Opin Pediatr, 2024.PMID 39400084
2. [2]Usatine RP, Sandy N. Dermatologic emergencies Am Fam Physician, 2010.PMID 20879700
3. [3]Wortsman X. Sonography of Dermatologic Emergencies J Ultrasound Med, 2017.PMID 28470978
4. [4]Gray L, Hansen AM, Cipriano SD Pediatric Staphylococcal Scalded Skin Syndrome: A Systematic Review of the Literature to Inform Work-Up and Management Pediatr Dermatol, 2025.PMID 40650480
5. [5]Leung AKC, Barankin B, Leong KF Staphylococcal-scalded skin syndrome: evaluation, diagnosis, and management World J Pediatr, 2018.PMID 29508362
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22. [22]Hsu FL, Tsai TF Epidemiological, Genetic, Clinical, and Treatment Differences of Generalized Pustular Psoriasis and Acrodermatitis Continua of Hallopeau Across Ethnicities: A Systematic Review Am J Clin Dermatol, 2025.PMID 40169503
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