Diarrhea is common in children and babies and normally resolves on its own. In its mildest form it can be caused by eating something new or by teething in younger babies. It’s common for children to pick up viral infections from food or each other at nursery and school – these are usually short-lived, and they recover within a few days. In acute diarrhea, the main risk is dehydration. If it lasts longer than two weeks, it’s called chronic diarrhea and is worth discussing with your doctor, even if they appear well – toddler's diarrhea is one cause of chronic diarrhea. We will talk you through the different causes, when to worry, and when to seek medical help.

Nausea and vomiting are common symptoms that can be caused by various factors such as motion sickness, migraine, anxiety, alcohol, medicines, and recent surgery.  The symptoms associated with nausea and vomiting depend on the underlying cause. Some common symptoms include an urge to vomit, or actual vomiting, not feeling like eating, severe headache, abdominal pain, vomiting blood, extreme weakness, high fever (over 101.3°F) blurred vision or eye pain, confusion, or stiff neck. How does it occur? The mechanism for nausea and vomiting is complex and involves many physiological processes. The vomiting center in the brainstem controls vomiting. The inner ear, intestines, and chemoreceptor trigger zone (CTZ) send information to the center. The brain's CTZ contains dopamine, serotonin, opioid, acetylcholine, and substance P receptors. Activating these receptors can cause nausea and vomiting. When activated, the CTZ sends signals to the brainstem vomiting center. The hub coordinates activities that cause vomiting. Increased salivation, deep breathing to prevent aspiration, heaving or retching before vomiting, and pyloric sphincter relaxation, which guards the lower end of the stomach, are examples of these phenomena.

It's common for children to get minor injuries to the hip, leg, or foot that could cause them to limp – this might be a cut or bruise, a blister on their foot, or a muscle strain or sprain. While limping is not usually anything serious or that needs treatment, it's important to look out for signs that something more serious is causing a limp, and get them to their doctor for a thorough assessment. A good starting point is whether there's an obvious injury – they might remember falling over or playing sports, or you may be able to see the cause. Minor injuries will not cause other symptoms, so look out for any fever, excessive tiredness or inactivity, warmth or redness around a joint, or pain that's not improving after a week or so. Inflammatory conditions, deep infections, broken bones, or developmental problems are serious problems that need specialist input.

If you’re dealing with knee pain, you’re not alone. It’s a very common problem that many people experience every day and it can be brought on by lots of different things. The likely cause of your knee pain will depend on how or when it started, its location and if there are any other associated symptoms.

COVID-19 is a virus that can affect all systems, and while most think first of it as threatening our breathing, it can also present a considerable burden to the skin. Doctors have seen increased numbers of skin rashes and irritations, and there’s anecdotal evidence that it can impair wound healing. For 1 in 5 with COVID-19, a skin sign is the only symptom they have. COVID-19 skin signs fall into two categories – common conditions that have become much more common, such as urticaria, and rare conditions that have increased, such as those affecting the toes or mouth. It’s not clear if the virus causes these changes directly or via the immune response it provokes, but nearly half appear at the time of infection – about a third appear after infection. It’s worth noting that it’s common to get a rash after any mild viral illness, such as a cold.

Chest pain is a broad term, and feels very different depending on the cause. Most chest pain is not anything serious, but cause for concern depends on your particular symptoms, your age and any other medical problems or risk factors you might have for heart problems. Chest pain can be a sign of something serious and life-threatening, such as a heart attack. If there are any concerns, you should seek immediate medical attention. Symptoms can vary from short, sharp jabs, to dull and persistent aches. People are usually very specific about how it feels, and other descriptive terms include feeling heavy, tight, burning, crushing or searing. It can come on quickly or gradually. It can be fleeting for seconds to minutes, or last several hours. It can occur while walking or exercising, lying down or when sitting doing nothing, and you might notice other symptoms alongside, like a cough, sweating, feeling sick or feeling the heart beating fast or hard. All of these specifics help doctors to determine which part of the body is causing the pain and what the underlying problem is. Let’s talk you through the causes, depending on which part of the body is involved, and also, importantly, when you should worry.