What causes redness and itchiness on the inside of the labia minora?

The inside of the labia minora is the vagina. The itching that causes it is mostly considered to be related to vaginitis. There are many types of vaginitis, and the specific cause can only be known after an examination. Vaginitis is generally caused by sexual intercourse or lack of attention to hygiene in daily life. You must change your underwear frequently and pay attention to personal hygiene.

1. Bacterial vaginosis

In a normal vagina, lactobacilli that produce hydrogen peroxide are dominant. Bacterial vaginosis is an endogenous mixed infection caused by a decrease in Lactobacillus and an increase in Gardnerella and anaerobic bacteria in the vagina.

2. Candidal vaginitis

(1) 80% to 90% of pathogens are Candida albicans, which grow easily in an acidic environment and are diphasic bacteria (yeast phase and hyphae phase).

(2) The patient's vaginal pH is 4.0-4.7, and usually less than 4.5.

(3) Conditionally pathogenic bacteria (yeast phase → mycelium phase).

(4) Common causes: pregnancy, diabetes, and large-scale use of immunosuppressants and broad-spectrum antibiotics.

(5) Other contributing factors: gastrointestinal Candida, wearing tight synthetic underwear, and obesity.

3. Trichomonas vaginitis

(1) Trichomonas vaginalis grows best in a humid environment with a temperature of 25℃ to 40℃ and a pH of 5.2 to 6.6.

(2) The vaginal pH changes before and after menstruation, becoming close to neutral after menstruation, making it easier for Trichomonas to reproduce.

(3) The patient's vaginal pH is generally between 5.0 and 6.5, with most cases being > 6.0.

(4) Parasitic on the vagina, urethra or paraurethral glands, bladder, renal pelvis, male foreskin folds, urethra, and prostate.

(5) Often coexists with other vaginitis.

4. Senile vaginitis

Postmenopausal women have declining ovarian function, lower estrogen levels, vaginal wall atrophy, thinning mucosa, increased vaginal pH, reduced local resistance, and other pathogenic bacteria may over-multiply or easily invade and cause inflammation, mainly aerobic bacteria.

5. Vaginitis in young girls

It is caused by poor development of the vulva, low estrogen levels and foreign objects in the vagina of infants and young children, which trigger infection. Common pathogens include Escherichia coli, Staphylococcus aureus, Streptococcus aureus, etc.