What are the possible medical and psychiatric causes of anxiety in a patient presenting with restlessness, insomnia, panic‑type breathing difficulty, irritability, loss of appetite, diarrhea, nasal congestion, and a sensation of insects crawling on the skin?

What Can Cause These Severe Anxiety Symptoms?

Your constellation of symptoms—restlessness, insomnia with panic awakenings, inability to breathe or relax, sensation of bugs crawling on skin, irritability, inability to eat, diarrhea, and nasal congestion—requires immediate evaluation for both medical and substance-related causes before attributing them to a primary anxiety disorder. 1

Immediate Differential Diagnosis Priority

Medical Causes Must Be Ruled Out First

First treat medical causes of anxiety (such as unrelieved symptoms like pain and fatigue) and delirium (such as infection or electrolyte imbalance). 1 Your symptoms could indicate:

Cardiovascular emergencies:

• Acute coronary syndrome (chest discomfort, breathing difficulty, sweating)
• Cardiac arrhythmias (palpitations, panic-like episodes)
• Heart failure (dyspnea, inability to lie flat, restlessness)

Respiratory crises:

• Pulmonary embolism (sudden breathing difficulty, panic, restlessness)
• Severe asthma exacerbation (dyspnea, nasal congestion, inability to relax)
• Chronic obstructive pulmonary disease decompensation

Neurological conditions:

• Seizure disorder (panic-like episodes, altered consciousness)
• Delirium from infection, metabolic disturbance, or hypoxia (confusion, restlessness, inability to focus)

Endocrine disorders:

• Hyperthyroidism (restlessness, inability to sit still, diarrhea, irritability, insomnia)
• Pheochromocytoma (episodic panic, sweating, palpitations)
• Hypoglycemia (panic-like symptoms, sweating, inability to focus)

Substance-Induced Causes Are Critical

Medical and substance-induced causes of anxiety should be diagnosed and treated. 1 The sensation of bugs crawling on your skin (formication) is particularly concerning for:

Substance intoxication:

• Stimulant use (cocaine, methamphetamine, excessive caffeine)
• Anticholinergic toxicity

Substance withdrawal:

• Alcohol withdrawal (restlessness, insomnia, autonomic hyperactivity, GI symptoms)
• Benzodiazepine withdrawal (severe anxiety, insomnia, panic, GI disturbance)
• Opioid withdrawal (restlessness, diarrhea, insomnia, irritability)

Medication side effects:

• Corticosteroids (anxiety, insomnia, irritability)
• Bronchodilators (tremor, restlessness, palpitations)
• Decongestants (anxiety, insomnia, restlessness)
• Thyroid hormone excess
• Stimulant medications

Primary Psychiatric Anxiety Disorders (Only After Medical Causes Excluded)

If medical and substance causes are ruled out, your symptoms align with several anxiety disorder presentations 2:

Panic Disorder:

• Recurrent unexpected panic attacks with abrupt surge of intense fear
• Physical symptoms: inability to breathe, palpitations, sweating, trembling
• Panic awakenings from sleep are characteristic
• Anticipatory anxiety about future attacks

Generalized Anxiety Disorder:

• Excessive, uncontrollable worry about multiple areas
• Restlessness, inability to sit still
• Difficulty concentrating (inability to watch TV or read)
• Sleep disturbance
• Irritability
• Muscle tension
• Fatigue

Psychophysiological Insomnia:

• Heightened arousal preventing sleep
• "Racing thoughts" and heightened environmental awareness
• Vicious cycle of arousal, poor sleep, and frustration 3

Critical Red Flags Requiring Emergency Evaluation

For any patient identified as at risk of harm to self and/or others, clinicians should refer to appropriately trained professionals for emergency evaluation. 1 Seek immediate care if you experience:

• Thoughts of harming yourself or others
• Severe agitation or confusion
• Chest pain or severe breathing difficulty
• Signs of delirium (confusion, disorientation)
• Psychotic symptoms (hallucinations beyond the crawling sensation)

Recommended Evaluation Pathway

1. Urgent medical evaluation to assess vital signs, cardiac function, oxygen saturation, thyroid function, electrolytes, and toxicology screen
2. Comprehensive medication review including all prescriptions, over-the-counter drugs, supplements, and substances
3. Substance use assessment including alcohol, caffeine, nicotine, and recreational drugs 4
4. Physical examination focusing on cardiovascular, respiratory, neurological, and endocrine systems
5. Psychiatric diagnostic assessment only after medical causes are excluded 5, 1

Common Pitfalls to Avoid

The most dangerous error is attributing these symptoms to "just anxiety" without medical workup. A patient with deteriorating cardiac or pulmonary function may be misidentified as primarily anxious, and the change in medical status is missed until the situation becomes critical 6.

The formication (bugs crawling sensation) is particularly concerning and should never be dismissed as simple anxiety—it strongly suggests substance use, withdrawal, or medical pathology requiring immediate investigation.

Your inability to lie down and relax combined with breathing difficulty could indicate cardiac or pulmonary emergency rather than anxiety alone. The combination of GI symptoms (diarrhea, inability to eat) with severe anxiety symptoms warrants evaluation for thyroid disease, substance withdrawal, or other metabolic disturbances 7.