A true dermatologic emergency is a skin disorder that threatens life or functional outcomes and requires immediate treatment. These emergencies include allergic reactions and severe skin infections, which require rapid management to prevent serious or fatal complications.

At the 2025 Dermatology Days of Paris conference, Camille Hua, MD, a dermatologist in the Department of Dermatology at Henri Mondor University Hospital in Créteil, France, discussed various skin conditions that require urgent recognition and treatment.

Drug Reactions

Drug-induced skin reactions should be suspected when an acute rash develops after exposure to a new medication within the previous 8 weeks. The cornerstone of management is the identification and immediate discontinuation of the suspected causative drug.

Any medication can cause a drug-induced skin reaction, although certain agents are more frequently implicated than others, particularly in severe cases. These include antibiotics, especially antibacterial sulfonamides such as cotrimoxazole; several antiepileptics, notably carbamazepine and lamotrigine; allopurinol; nevirapine; and certain nonsteroidal anti-inflammatory drugs.

More than 90% of drug-induced skin reactions are benign, with severe forms being rare. Severe drug reactions include epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis.

Epidermal necrolysis, which includes Stevens-Johnson syndrome (< 10% body surface area) and Lyell syndrome (> 30%), is the most severe drug-induced reaction. It is characterized by epidermal necrosis, leading to detachment of the skin and mucous membranes, including ocular, oral, and genital involvement.

This condition is life-threatening, with an estimated acute phase mortality rate of 15%-20%, primarily because of infectious and respiratory complications. Although rare, occurring in approximately 2-6 cases per million people per year, epidermal necrolysis is drug-induced in approximately 70% of cases and typically develops 4-28 days after exposure. Supportive management is provided in an ICU, as no specific treatment has demonstrated efficacy based on high-quality evidence. 

DRESS Syndrome

DRESS is a rare but potentially severe drug reaction that affects approximately 10 individuals per million in the general population. It combines cutaneous manifestations with visceral involvement, including hepatic, renal, and cardiac complications that may be life-threatening.

DRESS typically develops 2-8 weeks after the initiation of the causative medication. Clinical features include facial edema; a widespread rash, often involving more than 50% of the body surface area or progressing to erythroderma; high fever; diffuse lymphadenopathy; and laboratory abnormalities, most notably eosinophilia.

Topical corticosteroids may be sufficient for mild cases. Systemic corticosteroid therapy is required for severe or life-threatening visceral involvement.

Anaphylactic Shock

Anaphylactic shock is a severe, immediate hypersensitivity reaction involving at least two organ systems that poses an immediate threat to the life of the patient. It occurs rapidly after exposure to an allergen, most commonly food, medications, or Hymenoptera venom.

Diagnosis is based on acute onset, within minutes to a few hours (< 2 hours), of generalized urticaria with pruritus of the palms and soles, associated with respiratory signs such as laryngeal edema, voice changes, and cardiovascular symptoms. Management is emergent and includes calling emergency medical services, placing the patient in the Trendelenburg position, and administering intramuscular epinephrine at a dose of 0.01 mg/kg, up to a maximum of 0.5 mg.

Necrotizing Skin Infections

Necrotizing bacterial dermohypodermitis, including necrotizing fasciitis, is a severe bacterial infection of the deep cutaneous tissues, involving the dermis and hypodermis, which may extend to the muscle and progress rapidly. These conditions are sometimes referred to as gangrene or “flesh-eating bacterial” infections.

Although rare, with an estimated incidence of 3-4 cases per 100,000 people per year, mortality remains high, at approximately 20%-40%.

These infections are most often polymicrobial, with group A beta-hemolytic streptococcus being the most common monomicrobial pathogen.

These conditions represent both medical and surgical emergencies. Early diagnosis and prompt surgical intervention are the major prognostic factors.

Warning signs include cyanotic areas, cutaneous necrosis, severe pain disproportionate to the physical findings, and signs of severe sepsis, such as hypotension, tachycardia, and confusion. Management requires broad-spectrum antibiotics, aggressive treatment of sepsis, and urgent, extensive surgical debridement, which may necessitate amputation in some cases.

Toxic Shock Syndrome

Staphylococcal and streptococcal toxic shock syndromes are rare but severe systemic infections caused by the production of toxins, including toxic shock syndrome toxins.

Streptococcal toxic shock syndrome is often associated with severe skin infections such as necrotizing fasciitis. Staphylococcal toxic shock syndrome, typically associated with tampon or menstrual cup use, affects young women.

The clinical features include hypotension, multiorgan failure, fever, and diffuse erythema without spared skin, accompanied by mucous membrane involvement. After 1-2 weeks, characteristic palmar and plantar desquamation may occur.

Treatment includes management of shock, targeted antibiotic therapy against Staphylococcus or Streptococcus (combined with clindamycin for its antitoxin effect), and eradication of the infectious focus, which may involve surgical debridement or removal of intravaginal devices.

Staphylococcal Scalded Skin Syndrome

Staphylococcal scalded skin syndrome is a rare but severe complication of staphylococcal infection, characterized by erythema and superficial epidermal detachment.

This condition is caused by exfoliative toxins A and B produced by Staphylococcus aureus. It is rare in adults, with an incidence of approximately 0.98 cases per million, but it is more common in children, with an estimated 7.6 cases per million in the US.

Skin involvement ranges from localized to diffuse epidermal detachment and is accompanied by systemic symptoms such as fatigue, fever, and pain. Management requires hospitalization, antistaphylococcal antibiotics, and drainage of any underlying infection.

Purpura and Fulminant Presentations

Purpura is a hemorrhagic lesion of the skin or mucous membrane that does not blanch under pressure. Key considerations include association with fever; signs of severe sepsis, such as hypotension, oliguria, or mottling; and the presence of necrotic or ecchymotic lesions larger than 3 mm that spread rapidly over hours.

In such cases, purpura fulminans should be considered. This diagnosis requires immediate prehospital administration of 1 g of ceftriaxone intramuscularly or intravenously, regardless of the hemodynamic status, followed by urgent intensive care management.

No diagnostic tests are required to establish the diagnosis. The two main causative bacteria were meningococcus and pneumococcus. Skin biopsy may provide bacteriologic information within 3-4 hours.

Once purpura fulminans has been ruled out, purpura may arise from either a thrombocytopenic cause, due to reduced platelet counts, or a vascular cause, reflecting inflammation of the cutaneous vessel wall.

This story was translated from Medscape’s French edition.