Onychomycosis is caused most commonly by Trichophyton rubrum or T. mentagrophytes. About 10% of all persons worldwide and 40% of those ≥60 years old are believed to have the disease. Risk factors include older age, diabetes, poor peripheral circulation, smoking, HIV infection, psoriasis, and immunosuppression. Left untreated, onychomycosis can cause nail plate destruction, ingrown nails, and (particularly in patients with diabetes) secondary infections. Guidelines on treatment of onychomycosis have been published.

The goal of asthma treatment is to control symptoms, prevent exacerbations, and maintain normal lung function. Management of acute exacerbations in the emergency department is not discussed here.

Consumption of alcohol has increased during the COVID-19 pandemic. The Diagnostic and Statistical Manual for Mental Disorders, 5th edition (DSM-5) defines alcohol use disorder (AUD; previously called alcohol dependence) as meeting ≥2 of the 11 criteria listed in Table 1 in the past year. The lifetime prevalence of AUD in the US population has been estimated to be about 30%. Despite this high prevalence and the associated morbidity, mortality, and costs, only 3 drugs are FDA-approved for treatment of the disorder.

Bipolar disorder is characterized by episodes of mania, hypomania, and depression. Recurrences of manic or (more frequently) depressive symptoms are common. About 15-20% of patients with bipolar disorder die by suicide.

Annual vaccination against influenza A and B viruses is recommended in the US for everyone ≥6 months old without a contraindication. Influenza vaccines available in the US for the 2025-2026 season are listed in Table 2.

Influenza is generally a self-limited illness, but complications including pneumonia, respiratory failure, and death can occur, especially in persons at increased risk (see Table 1).

The main goals of treatment of chronic obstructive pulmonary disease (COPD) are to relieve symptoms, reduce the frequency and severity of exacerbations, prevent disease progression, and reduce mortality. GOLD (Global Initiative for Chronic Obstructive Lung Disease) guidelines for treatment of COPD were updated recently. Treatment of acute exacerbations is not discussed here. Drugs available for treatment of COPD are listed in Tables 1 and 3.

An oral nonopioid analgesic is often sufficient for acute treatment of mild to moderate migraine pain without severe nausea or vomiting. A triptan is the drug of choice for treatment of moderate to severe migraine in most patients without vascular disease. Treatment of pain when it is still mild to moderate in intensity improves headache response and reduces the risk of recurrence.