Dear Doctor, Why do I develop pimples whenever I am experiencing my periods? Anette Dear Anette, An average menstrual cycle is about 28 days, plus or minus one week. The first 14 days are dominated by the hormone estrogen and the last 14 days are dominated by progesterone. Regular menstrual cycle depends on the balance of these two hormones. But levels of testosterone remain constant throughout the cycle. Due to higher levels of progesterone and indirect higher levels of testosterone, higher levels of sebum builds up in later half of the cycle. This leads to blocking of skin pores and the bacteria P. acnes to grow and multiply. There is also underlying inflammation causing redness and swelling of skin. Sixty-three per cent of women who are prone to acne around the world experience flare of acne before or in early menses. This is associated with other pre menstrual symptoms like cramps in legs, pain in the lower abdomen, weaknesses, nausea and or vomiting. This flare up subsides within 7-10 days only to recur in subsequent cycle. Acne during menstruation is not related to hygiene, but it is an internal thing of the body. One cannot do much to alter it, but it can be minimised. A woman with acne. Pimples are very discomforting and can affect one’s esteem. (Net photo) Eating a healthy diet and taking regular exercise help minimise acne and also preventing obesity, which is a cause for aggravating acne. Though the problem is not directly linked to personal hygiene, improved hygiene can reduce acne during menses. Keep skin clean and dry and avoid greasy make up and use of greasy cosmetics on face. Birth control pills help reduce acne by increasing estrogen levels and reducing testosterone levels. But response to birth control pills becomes visible after 3-4 months of use. One who wishes to conceive or is already pregnant should discuss with her doctor before using birth control pills. These pills are associated with side effects like increase in lipid levels, making one more prone to diabetes, heart diseases, strokes and other cardiovascular problems. They also increase lipid levels in blood and increased coagulability, thus further increasing risk of cardiovascular problems. A woman using these pills should be aware of these side effects as well. Use of ointments containing tretinoins is also beneficial. It can produce side effects like irritation of skin on exposure to sun and birth defects during pregnancy. Low dose of antibiotics like erythromycin and doxycycline, also helps in clearing acne during menstruation. These can be started 5 to 7 days before menstruation. In case of severe acne or those not responding to other simple treatments, a dermatologist can try other treatments like local injection of cortisone or derm peeling. Dr Rachna Pande is a specialist in internal medicine at Ruhengeri Hospital