The most common cause of itching in the underarms is an allergic reaction to cosmetics: shaving gel, deodorant, soap, etc. Deodorants, antiperspirants often the culprits of allergic reactions. If a skin reaction occurs again and again, try to choose a line marked sensitive or "for sensitive skin". You may also suitable for organic media. The disadvantage of such antiperspirants is that they are quite expensive, and protection from odor and sweat does not last long, about 6-8 hours. If a new tool was allergic to, then do not use it and skin reaction will pass by itself within 24-48 hours. If you are experiencing severe discomfort and itching prevents you from sleeping, take an antihistamine.
If you shave armpits, there is nothing strange that you are often worried about itching in this area. There are several reasons for its occurrence. First, growing hairs irritate the delicate skin of the armpits. There is redness, irritation; the situation is exacerbated by the possible ingrown hairs. Secondly, the skin in the shaving process damaged blade, but via small scratches and cracks in it can get infected. In this case there is intense itching, redness and pain. Also owner sensitive skin may face the intolerance the rough synthetic fabrics. Clothing made of synthetics breathes badly. Due to the lack of air circulation, the person strongly sweats. High humidity is irritating to the underarm skin, causing itching. The same applies to fleecy fabrics and tight-knit. Try to choose clothes and underwear with a high content of natural fibers.
In certain endocrinological or neurological diseases there is excessive sweating or hyperhidrosis. Heavy sweating and, as a consequence, itching in the underarms accompany various disorders of the autonomic nervous system, in particular, vegetative-vascular dystonia. And in violation of the endocrine system and changes in hormonal levels may experience changes in the composition of sweat. It becomes more caustic to the skin. In order to verify the presence of hormonal disorders, it is necessary to hand over analyses on hormones of a thyroid gland and to consult endocrinologist.