Menopause: This is the most common cause of hot flashes, especially in women between the ages of 45 and 55. The decline in estrogen levels during menopause leads to vasomotor symptoms, including hot flashes and night sweats.

Perimenopause: The transition period leading up to menopause, during which hormone levels fluctuate, can also cause hot flashes.
Hormone Therapy Withdrawal: Stopping or reducing hormone replacement therapy (HRT) can lead to hot flashes in some women.
Thyroid Disorders: Hyperthyroidism, in particular, can cause hot flashes due to an overproduction of thyroid hormones.
Medications: Certain medications, such as antidepressants and blood pressure medications, can induce hot flashes as a side effect.

Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodic hot flashes, along with hypertension, palpitations, and headaches. Missing this diagnosis could be life-threatening.
Carcinoid Syndrome: A rare condition caused by a neuroendocrine tumor that can produce hot flashes, along with flushing, diarrhea, and wheezing.
Hypogonadism: Low testosterone levels in men can cause hot flashes, and underlying conditions such as pituitary or testicular disorders need to be ruled out.

Neurological Disorders: Certain conditions, such as multiple sclerosis, can cause hot flashes, although this is relatively rare.
Infections: Some infections, like tuberculosis, can cause night sweats, which may be mistaken for hot flashes.
Gastrointestinal Disorders: Conditions like pancreatic cancer or gastrinoma can cause flushing and hot flashes, although these are rare causes.
Mastocytosis: A rare condition characterized by an accumulation of mast cells, which can cause hot flashes, along with flushing, itching, and gastrointestinal symptoms.