The term, contact urticaria, has a wider use in dermatology, involving dermatitis caused by various skin irritants and pathogens.Docks, especially the broad-leaf dock (Rumex obtusifolius) often grow in similar environments to stinging nettles and are regarded as a folk remedy to counteract the sting of a nettle, although there is no evidence of any chemical effect. It may be that the act of rubbing a dock leaf against a nettle sting acts as a distracting counterstimulation, or that belief in the docks effect provides a placebo effect. Uses
Culinary
U. dioica has a flavour similar to spinach when cooked. Young plants were harvested by Native Americans and used as a cooked plant in spring when other food plants were scarce. Soaking stinging nettles in water or cooking removes the stinging chemicals from the plant, which allows them to be handled and eaten without injury. After the stinging nettle enters its flowering and seed-setting stages, the leaves develop gritty particles called cystoliths, which can irritate the kidneys and urinary tract. : 106–107   Cystoliths are made of calcium carbonate, and will not dissolve when boiled. Leaves harvested post-flowering must have their cystoliths broken down by acid, as in the fermentation process. In its peak season, nettle contains up to 25% protein, dry weight, which is high for a leafy green vegetable. The leaves are also dried and may then be used to make a herbal tea, as can also be done with the nettles flowers. Nettles can be used in a variety of recipes, such as polenta, pesto, and purée.
According to Robert E. Black of the Johns Hopkins School of Public Health (JHSPH), "Underweight status ... and micronutrient deficiencies also cause decreases in immune and non-immune host defenses, and should be classified as underlying causes of death if followed by infectious diseases that are the terminal associated causes." People who are malnourished raise special concerns, as not only gross caloric intake may be inadequate, but also intake and absorption of other vital nutrients, especially essential amino acids and micronutrients such as vitamins and minerals.In women, being severely underweight, as a result of an eating disorder or due to excessive strenuous exercise, can result in amenorrhea (absence of menstruation), infertility or complications during pregnancy if gestational weight gain is too low.Malnourishment can also cause anemia and hair loss. Being underweight is an established risk factor for osteoporosis, even for young people. This is seen in individuals suffering from relative energy deficiency in sport, formerly known as female athlete triad: when disordered eating or excessive exercise cause amenorrhea, hormone changes during ovulation leads to loss of bone mineral density. After this low bone mineral density causes the first spontaneous fractures, the damage is often irreversible. Although being underweight has been reported to increase mortality at rates comparable to that seen in morbidly obese people, the effect is much less drastic when restricted to non-smokers with no history of disease, suggesting that smoking and disease-related weight loss are the leading causes of the observed effect. Treatment
Diet
Underweight individuals may be advised to gain weight by increasing calorie intake.