Causes of flushing, also known as blushing, hot flushes or hot flashes, are many. It is usually seen on the cheeks, sides of neck, ears and front of chest and is caused by dilatation of blood vessels (known as vasodilatation) within the skin.
Broadly, flushing may occur due to the presence of chemical mediators called vasodilators in the blood, like histamine, causing the vasodilatation or due to the stimulation of the blood vessels by the autonomic nervous system. As sweat glands are also supplied by the autonomic nervous system, sweating occurs in this type of flushing, the wet flushing. In the flushing caused by vasodilators, sweating is usually absent, the dry flushing.
Physiological Flushing
An important function of skin is temperature control of the body, during which there is vasodilatation and increased blood flow to the skin . An exaggerated response of this physiological flushing can occur in a hot environment, feverishness, after exercise or drinking hot fluids.
Embarrassment or anger causes emotional flushing in many people through the neurological stimulation.
Menopausal Flushing
About 80% women during menopausal develop flushing and sweating following emotion, exertion or hot spicy food and drink. This is due to hormonal changes inducing disturbance in the thermoregulatory mechanisms.
Drug Induced Flushing
Flushing is a common side effect of vasodilator medications used to treat hypertension, or increased blood pressure. 10-20% of cases of patients taking sildenafil for erectile dysfunctions experience flushing and headaches. Some other drugs that may cause flushing are gold salts, phentolamine, pilocarpine, prostaglandin E, nicotinic acid, prostacyclin etc.
Flushing and Alcohol Intake
The flushing caused by alcohol is common, especially in Orientals. Orientals get flushing even with low doses of alcohol. Alcohol gets metabolized to acetaldehyde faster in them than in other genotype of human beings. Acetaldehyde produces flushing mostly by release of histamine from the mast cells.
Diabetics on the anti diabetic medication chlorpropamide frequently experience intense flushing within a few minutes of alcohol ingestion. Disulfiram (used to treat alcohol dependency) and metronidazole also produces similar effects with alcohol.
Flushing Caused by Food
Hot, spicy and sour food can evoke flushing and sweating in most people, this is known as gustatory flushing and involves an autonomic neuron nerve reflex involving the trigeminal nerve.
Flushing in Scombroid Fish Poisoning
Fish belonging to the scombroid family, which includes tuna and mackerel, and some non scombroid fishes like herring, if not fresh, can cause symptoms of scombroid fish poisoning. Within a few minutes of ingestion of the spoiled fish, the patient experiences flushing, sweating, vomiting and diarrhea. These stale (decaying) fishes contain high amounts of histamine, which is responsible for the dramatic symptoms.
Flushing in Carcinoid Syndrome
Carcinoid syndrome results from secretion of hormonal and other chemical substances by cancerous growths most often found in the appendix and small intestine. Flushing is observed in 80% cases of carcinoid syndrome, often precipitated by exercise, alcohol, stress and certain foods, like chocolate, red wine, blue cheese etc.
Other causes of Flushing
Persistent flushing is present in hyperthyroidism, mastocytosis, medullary carcinoma of thyroid, pancreatic cancers, insulinoma, and POEMS syndrome ( a multisystem disease involving peripheral nerves, internal organ enlargement, endocrine gland abnormalities, protein abnormalities and skin changes including flushing, hyper pigmentation, increased hair growths, hemangiomas, white nails etc). The redness in the blush areas in rosaceous and lupus erythematosus is not considered as flushing, as the skin rash, called malar rash, is often a permanent feature.
Unexplained, frequent and intense episodes of flushing thus calls for in depth investigations to rule out the more sinister causes of the hot flushes. Treatment of flushing depends upon the specific causes.
Reference
 |
 |
