How Acne Forms : 4 states.
Stage 1 : A clogged Pore (hair follicle). Your skin cells are constantly renewing, when old cells die they shed, And they reveal fresh skin but if your acne prone, sebum mixes with the dead skin cells, becomes sticky substance and block the pores.
Dead Skin cells + Sticky Sebum ---> blocks the pore
Stage 2: Production of oil inside the pore. Normally the oil produced inside the port flows out through the 4 but since the pore is blocked the all stay inside. Androgen hormone stimulates oil production But during stress and puberty Androgen level is increased. Somo oil is produced and the more blockage of what happens because of excess oil in dead skin cells and the oil which is produced inside build some pressure inside the pore.
Stage 3: bacteria p acnes which are naturally present in all skin types, Now have an abundant supply of food which is dead skin cells and Starts to breathe inside the Pore
Stage4:: Inflammation. The white blood cells rush to the area where there is excess bacteria and starts fighting. This causes redness and swelling which is the actual pimple you see
Hormones ( Cause 1)
Androgen/ Testosterone- this hormone is linked to the oil production in the oil glands of the skin And shedding of dead skin cells. so when excess oil is produced and the skin cell not shed naturally the force can be blocked and then the formation of acne starts.
Cortisol or stress hormone make you produce excess oil in your skin. Stress in the short term might be gold to meet your deadlines but long-term stress can result in increased cortisol levels which will give you more acne
Insulin - Scientist have found that more insulin means more acne. Insulin hugely increases your sebum production, actually a lot more than testosterone. Studies on diet and acne have found that low sugar and low GI diets reduce or even completely eradicate acne. So What your blood sugar levels. And to Be on the safe side take low glycemic index diet.
Genetics ( Cause 2)
Genes to some extent determine sebum production level and how skin responds to hormonal changes, stress, and inflammation. But there is no such thing as Acne Gene. So don't blame your genes but start working on things you can control like stress and hormones.
Oil and water balance in skin
Our sebum consists of both oil and water. When our skin is dehydrated (low levels of water in our skin) , our skin tries to produce more sebum to compensate for the water loss. Hence more oil is produced which is not desired for acne-prone skin.
Pollution & Environment (Cause 3)
Heat - can increase oil production in skin so more chances of breakouts. So during hot days, keep a facial tissue handy.
Humidity - In winter months there is low humidity and and skin gets dry with low water lavels, this will cause the skin to produce excess sebum( Combination of oil and water). THis excess oil might cause you more breakouts. So its important to keep your winter skin hydrated.
Sun exposure for short time might be helpful, as blue band of light helps to sterilizr the acne bacteria. But prolonged sun exposure oxidises you sebum, and increases the shedding of dead skin cells. This is perfect scenario for pore to be blocked.
Sunscreens ( Cause 4)
Sunscreens - Heavy sunblocks (Mineral sunscreens) have a lot of oil in them, which can block the pores. And chemical sunscreens work by absorbing UV light, which can increase the temperature in the inside the pore. This might again cause more acne. So your best option would be to go for small SPFs. Many skincare experts agree that SPF 15-20 is more than enough. But apply every 3 horus if you are in out the sun. May be avoid longer exposure to sun, exposing 30 min to sun 4 times a day is a lot less damaging than sun exposure for 2 continuous hours. Higher SPFs usually contain very heavy oil or have a lot of sun filters which might increase temperature inside the pore.