Stevens-Johnson syndrome and toxic epidermal necrolysis: Clinical sciences

Stevens-Johnson syndrome, or SJS, and toxic epidermal necrolysis, or TEN for short, are rare immune-mediated mucocutaneous conditions characterized by widespread blistering and sloughing. The exact cause of these conditions is still not fully understood, but it is thought to involve type 4 hypersensitivity against certain antigens, including different medications and pathogens. Now, Stevens-Johnson syndrome is associated with less than 10% of epidermal detachment, while in TEN, there's more than 30% of the skin affected. Finally, the Stevens-Johnson syndrome-TEN overlap describes epidermal detachment of more than 10% but less than 30%.

Now, if your patient presents with a chief concern suggesting Stevens-Johnson syndrome or TEN, first, perform an ABCDE assessment to determine if they are unstable or stable. If unstable, stabilize the airway, breathing, and circulation; obtain IV access, and start IV fluids. Next, put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry. Finally, provide supplemental oxygen to maintain oxygen saturation greater than 90%, and don’t forget to discontinue suspected triggering medications.

Here’s a clinical pearl! In severe cases, Stevens-Johnson syndrome and TEN can cause extensive skin damage, which can leave your patient vulnerable to severe dehydration, electrolyte imbalances, severe pain, infections, and hypothermia. Because of that, these severe cases are often managed in a burn intensive care unit. It’s important to make sure that your patient is properly hydrated and provide them with pain relief medications, like acetaminophen and opioids. Additionally, encourage sterile handling of the patient to prevent secondary infection and ensure that they’re in a warm area to prevent hypothermia.

Now, let’s return to the ABCDE assessment and take a look at stable patients. In this case, obtain a focused history and physical exam. Your patient will typically report flu-like symptoms, such as fever, usually above 39 degrees Celsius, as well as cough and sore throat. Additionally, they will report a rapid onset of pain and rashes affecting the skin and the mucosa. Other findings might include chest pain, a recent history of medication changes, infection, or prior drug reaction.

Here’s a high-yield fact! Medications commonly known to trigger Stevens-Johnson syndrome and TEN include anticonvulsants like phenytoin and carbamazepine, antibiotics like sulfonamides, anti-inflammatories like sulfasalazine, and certain NSAIDs. Additionally, infections associated with Stevens-Johnson syndrome and TEN include Mycoplasma pneumoniae, HIV, Cytomegalovirus, and Herpes infections.

Alright, moving on to the physical exam, which typically reveals an ill-appearing patient with conjunctivitis! In early stages, you will find atypical, flat or slightly raised, painful, dusky target-like lesions. On the flip side, in advanced stages, you will find widespread erythema, ulcers, and blisters affecting the skin and mucosa of the mouth, eyes, and genitalia. Next, if lateral pressure to the lesion causes the upper and lower layers of the epidermis to split, your patient has a positive Nikolsky sign, which is suggestive of these conditions. Finally, if there’s respiratory involvement, you could also hear lung crackles!

With these findings, you should suspect Stevens-Johnson syndrome or TEN. Your next step is to order labs, including a CBC, CMP, CRP, and ESR. Additionally, you should obtain blood cultures and a skin biopsy. Finally, if your patient has pulmonary symptoms, you might need to order chest imaging, such as an X-ray or CT scan.