Weed, insect, and disease control may also be required for pastures. A healthy, productive pasture will resist invasion from most poisonous weeds and provide good quality forage. When pastures are overgrazed, horses will eat the grass and legume species down to the soil, which allows weeds to take over.
1 Melasma can be triggered by birth control pills because it increases hormones throughout the body. # 2  This is one of the most common causes of melasma. 3  Pregnancy: During pregnancy the body will become very hormonal and skin conditions like acne vulgaris and melasma/chloasma become very common.
Most of the time, the cause of hives on face is never identified with 100% accuracy. However, there are some common triggers for angioedema and facial hives: Excessive sun exposure-even with sunscreen (see sun hives). Toiletries (soaps, shampoos, conditioners, etc.).