Leg pain, often felt in the late afternoon or at night, is a common complaint among children and causes concern in many families. In large part of these cases, the discomfort is linked to so-called growing pains, a condition considered benign that, despite its name, lacks scientific proof of being related to bone growth and still lacks specific treatment.
This is one of the most frequent causes of musculoskeletal pain in childhood, potentially affecting up to 20% of school-aged children, although the frequency varies according to studies. The symptom usually presents distinct characteristics: the pain manifests in both legs, concentrating mainly on the front of the thighs, calves, or the back of the knees, generally in the evening or at night. In some instances, the pain is intense enough to wake the child during sleep, but it completely subsides in the morning, without causing impediments to activities such as walking, running, or playing.
Since the causes of growing pains are not yet fully understood, current management focuses solely on symptom relief. In most situations, simple measures, such as massaging the painful area, using local heat, and stretching before bed, prove sufficient to reduce discomfort. However, when the pain is stronger, the use of analgesics may be considered, provided it is under medical supervision.
However, the scientific community has been investigating alternative therapeutic approaches. A pilot study conducted by researchers from the Federal University of São Carlos (UFSCar) and the Institute of Physics of USP São Carlos (IFSC/USP) suggests that the combination of ultrasound and low-intensity laser is safe and may help relieve childhood pain. Lucas Pereira Liberal, a medical student and co-author of the study, explained that current therapies rely heavily on symptomatic control with analgesics and anti-inflammatories, which are not always effective. The study's proposal was to develop a therapy specifically focused on growing pains, prioritizing the safety and well-being of children.
The findings of this pilot project were published in April in the Journal of Biophotonics. The experiment included nine children with a confirmed diagnosis of growing pains, divided into two groups: one received a session of low-intensity laser combined with ultrasound, while the other underwent the same procedure with the equipment deactivated (placebo group). Neither the participants, their guardians, nor the researchers knew which treatment each child was receiving.
The application of the therapy was performed on the soles of the hands and feet, not directly on the legs. According to Liberal, this regional choice is due to the analgesic properties of laser therapy combined with ultrasound. He detailed that these areas have high vascularization and innervation, which facilitates the absorption and systemic dissemination of the therapy's effects.
After the intervention, researchers noted a decrease in pain in the children who received the treatment, and no side effects related to the technique used were observed. The initial focus of the analysis was to verify the safety of the method, not its large-scale efficacy. Susana dos Reis Braga, a pediatric orthopedist at Einstein Israelite Hospital, emphasized that studies with a larger number of participants are necessary to determine if the method is truly effective and can be incorporated into clinical practice.
Causes and Diagnosis
The name of the condition can be misleading, as there is no proof that this pain is linked to bone growth or periods of growth acceleration. Susana dos Reis Braga mentioned that there are some theories, such as muscle fatigue, genetic predisposition, and, in certain cases, a possible link to iron or vitamin D deficiency, but none of these explanations covers all patients.
Although it causes discomfort, the condition is classified as benign; it does not cause lesions, does not harm child development, and tends to disappear naturally. Since there is no specific test to confirm the diagnosis, the evaluation is primarily based on clinical history and complementary exams. Certain clinical signs require deeper investigation, such as constant pain in only one leg, persistent symptoms during the day, difficulty moving, joint swelling, fever, weight loss, appearance of purple spots, or excessive tiredness. The doctor from Einstein warned that these signs may indicate other pathologies, whether orthopedic, rheumatological, infectious, or even hematological.