Testicular atrophy is a medical condition in which one or both testicles (or "testes") diminish in size and may be accompanied by reduced testicular function. Testicular atrophy is not related to the temporary shrinkage of the surrounding scrotum, which might occur in response to cold temperature.As the testicles are involved in testosterone and sperm production, the signs and symptoms of testicular atrophy overlap with those related to infertility or low testosterone levels. In a prepubescent person with testicular atrophy, there may be underdevelopment of secondary sex characteristics (e.g. lack of penis growth). In sexually developed individuals, testicular atrophy may be accompanied with lower sex drive and increased breast tissue. Additional signs and symptoms vary and can depend on the specific cause of the testicle shrinkage. Some causes include age, alcohol use, hormone therapy, direct damage to the testicles, and infection.Diagnosis of testicular atrophy includes physical examination of the testicles as well as imaging to measure testicular volume. A testosterone blood level is also taken to assess function of the testicles. Additional tests may be ordered depending on the suspected cause(s) of the shrinkage. Treatment and potential reversibility of testicular atrophy are also dependent on the cause. Signs and symptoms
There are different signs and symptoms associated with testicular atrophy depending on the persons age. Symptoms before puberty are centered more around the stunting of sexual characteristics associated with hormonal changes, while symptoms after puberty include a wider range of factors. Other signs and symptoms may stem from underlying conditions which cause testicular atrophy.
Hydrea may refer to: 

Hydra island
A brand name for the medication hydroxycarbamide