10 Dermatologic Emergencies You Should Know About

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  Erythema Multiforme Major

  Erythema multiforme major (EMM) is a hypersensitivity reaction that was previously thought to be part of a clinical spectrum including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis, but it is now considered a distinct clinical entity.^1,2 EMM is usually caused by an allergic reaction to pathogens, particularly herpes simplex virus (HSV; 50% of cases) and Mycoplasma pneumoniae, or to medications.^2,3 EMM is a targetoid rash involving <10% of body surface area and has some mucous membrane involvement.^2,3 Patients have a polymorphous eruption of macules, papules, and target lesions that are distributed symmetrically, typically originating in the distal extremities before spreading toward the trunk.^2,3

  Treatment may include systemic corticosteroids, intravenous immunoglobulin, plasmapheresis, and cyclosporine.³ Oral acyclovir and antibiotics may be used in cases of HSV and M pneumoniae infections, respectively.² Any triggering medications must be stopped.³

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  Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

  SJS and toxic epidermal necrolysis (TEN) are hypersensitivity reactions that present similarly to EMM, but with increased involvement of body surface area (BSA) and/or mucosal membranes. SJS is characterized by flat atypical target lesions and confluent purpuric macules on the face and trunk that involve <10% of BSA, but with ≥1 severe mucosal erosion, typically of oral or ocular mucous membranes.² TEN is more severe, with >30% BSA and ≥1 severe mucosal erosion that progresses to diffuse, generalized detachment of the epidermis. Patients with 10% to 30% BSA involvement are considered to have overlapping SJS and TEN.²

  Treatment is similar to that for EMM. Any triggering medications should be promptly withdrawn.^2-4 Systemic corticosteroids, intravenous immunoglobulin, plasmapheresis, cyclosporine, oral acyclovir, and antibiotics may be considered, depending on severity and the underlying cause. Fluid resuscitation and wound care are also essential.^2-4

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  DRESS Syndrome

  Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe idiosyncratic drug reaction that has a long latency period, with clinical symptoms often manifesting 2 to 8 weeks after initiating the triggering medication.⁵ Cutaneous manifestations vary, but most patients have a morbilliform skin rash.^3,5,6 Less commonly, there may be urticarial type eruptions, vesicles, bullae, pustules, purpura, target lesions, facial edema, cheilitis, and erythroderma.^5,6Other common features include fever, lymphadenopathy, eosinophilia, atypical lymphocytosis, and visceral involvement, which can result in hepatitis, pneumonitis, myocarditis, pericarditis, nephritis, and colitis.^5,6

  Prompt diagnosis is essential to ensure the triggering drug is discontinued immediately to improve prognosis.⁵ Supportive and symptomatic treatments may also be used, including corticosteroids and other immunosuppressants and liberal use of a greasy emollient.⁵

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  Cutaneous Anthrax

  Cutaneous anthrax is the most common form of anthrax infection, occurring when anthrax spores breach the skin through a cut or scrape.⁷Individuals who work with animals or animal products like wool or hides are at increased risk. Infection usually starts within 7 days of exposure.⁷ Key findings include regional lymphadenopathy and a painless skin ulcer with eschar surrounded by nonpitting edema.⁴ Skin ulcers most commonly appear on the arms, hands, face, or neck.⁷ Although cutaneous anthrax is the least dangerous form of anthrax, up to 20% of patients may die without treatment.⁷

  Cutaneous anthrax is initially treated with intravenous antimicrobial therapy and then switched to oral therapy.^4,8Adults may be given oral ciprofloxacin 500 mg twice daily or doxycycline 100 mg twice daily for 60 days.^4,8 Children are treated with the same agents, using pediatric dosing.^4,8 An intravenous multidrug regimen may be needed if there is systemic involvement, extensive edema, or if there are head and neck lesions.⁸

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  Necrotizing Fasciitis

  Necrotizing fasciitis is a rapidly progressive infection that can be caused by gram-positive, gram-negative, or polymicrobial organisms.⁹ In a matter of hours, these organisms can destroy subcutaneous tissue, nerves, blood vessels, and muscles; thus, prompt treatment is essential to save life and limb. Patients may have a red or swollen area of skin that expands rapidly, along with severe pain, fever, and other flulike symptoms.¹⁰ As the infection progresses, the skin becomes indurated, woody, and turns dusky blue.^9,10 Blisters filled with foul-smelling liquid may develop, and as gangrene sets in, there may be additional skin discoloration, peeling, and flaking.^9,10 Treatment requires rapid and extensive debridement until healthy tissue that is not purulent, necrotic, or woody to the touch is reached.^9,11Broad-spectrum antibiotics should also be administered, and intravenous immunoglobulin may be a useful adjunct in the setting of severe streptococcal infections.¹¹

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  Eczema Herpeticum

  Eczema herpeticum is an HSV infection superimposed on a preexisting skin condition, typically atopic dermatitis.³ Patients have monomorphic lesions that resemble the crusted stage of disseminated varicella. Lesions can appear anywhere on the body, including sites that have not been previously affected by the underlying skin condition, but the face and neck are common sites of infection.¹² Most patients also have secondary staphylococcal infections, which can lead to viremia and septicemia if not promptly recognized and treated.^3,12,13

  Eczema herpeticum is treated with acyclovir. Patients with more severe disease may require 24 to 48 hours of intravenous acyclovir before switching to oral therapy.^3,13 Those with concomitant staphylococcal infection require intravenous antibiotics. Choice of antibiotic depends on the level of methicillin-resistant Staphylococcus aureus in the community.³ Topical steroids may be needed in patients with active atopic dermatitis.¹²

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  Rocky Mountain Spotted Fever

  Rocky Mountain spotted fever results when Rickettsia rickettsii, a small gram-negative bacterium, is transmitted following a tick bite from the Rocky Mountain wood tick, the American dog tick, or as recently observed, the brown dog tick.^4,14 As R rickettsia spreads through the lymphatic system, it can affect all organs. Symptoms include fever, headache, and a rash that develops 2 to 5 days after the start of the fever, often delaying diagnosis.⁴ Initially, the rash consists of small, blanching, nonpruritic macules that evolve into a maculopapular rash and then into petechial lesions, with the characteristic spotted appearance resulting when the petechial lesions coalesce to form ecchymosis.⁴ The rash typically starts around the wrists and ankles, spreads to the palms and soles, and then spreads to the extremities and trunk.⁴

  Treatment within 5 days of symptom onset reduces the risk for death.⁴ Doxycycline is used as first-line therapy, but chloramphenicol is recommended for pregnant women.⁴

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  Toxic Shock Syndrome

  Toxic shock syndrome (TSS) is a toxin-mediated illness preceded by a bacterial infection, most commonly with Staphylococcus aureus or Streptococcus pyogenes.¹⁵ Although TSS is known to be associated with tampon use, it can occur after surgery, medical procedures, or childbirth; as a result of burns and soft tissue injuries; and from focal infections.¹⁵ Symptoms include sudden onset of high fever, rash, hypotension, renal or respiratory failure, confusion, hyperemia of mucous membranes, and/or strawberry tongue.^4,15,16 TSS rash resembles a sunburn and covers most of the body, with desquamation occurring over 1 to 2 weeks.⁴

  Treatment includes intravenous fluids, source control with early debridement of necrotic wounds, and use of penicillinase-resistant antibiotics.^4,15 Vasopressors may be used if blood pressure does not improve with intravenous fluids. ¹⁶ Some evidence suggests that intravenous immunoglobulin may improve mortality and reduce the need for wide debridement or amputation in people with unstable disease.¹⁶

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  Meningococcemia

  Meningococcemia occurs when there is dissemination of Neisseria meningitides into the bloodstream.¹⁷ Key findings include upper respiratory tract infection, malaise, weakness, confusion, irritability, headache, neck stiffness, arthralgias, and a characteristic skin rash that can help establish the diagnosis.^4,17 The rash usually starts as a few ill-defined lesions that progress quickly to a petechial rash, most commonly on the trunk and legs, and then to stellate purpura with a central gunmetal-gray hue.^4,17 Prompt diagnosis is essential to prevent significant morbidity and mortality, as N meningitides has been reported to be 100 times more virulent than other gram-negative organisms.¹⁸

  Patients with meningococcemia require intensive supportive care and rapid administration of intravenous or intramuscular antibiotics, with penicillin G preferred for susceptible isolates.⁴ Any complications resulting from the disease, such as neurologic issues or joint effusions, must also be addressed.¹⁷

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  Paraneoplastic Pemphigus

  Pemphigus is a group of autoimmune diseases that result in mucosal and skin blistering. There are 6 general types: pemphigus vulgaris, pemphigus foliaceus, pemphigus vegetans, pemphigus erythematosus, paraneoplastic pemphigus, and immunoglobulin A pemphigus.¹⁹ The most common is pemphigus vulgaris, which has mucosal involvement with or without skin involvement. The most serious is paraneoplastic pemphigus, which typically affects people with cancer.²⁰ This variant may include extensive intractable stomatitis and variable skin findings.⁶ Because presentations vary significantly among subtypes, pemphigus can easily be confused with other autoimmune blistering skin diseases such as bullous lupus, making bloodwork and biopsy essential for diagnosis.^20,21

  Treatment includes oral steroids, immunosuppressive agents, and antibiotics if there is infection.²¹ Good oral and wound care are essential.⁶ Tense blisters can be popped with a sterile needle to prevent traumatic deroofing.⁶