Nicotine is a type of stimulant found in tobacco products. Nicotine dependence occurs when your body gets used to having some level of nicotine in your system. In physical and psychological ways, your body “depends” on constantly having the chemical. Physical dependence is when your body needs nicotine to avoid withdrawal symptoms — the unpleasant feelings that you get when you stop using …

Mesenteric lymphadenitis, also known as mesenteric adenitis, is inflammation (swelling) of the lymph nodes in the abdomen (belly). Lymph nodes are organs that are part of your body’s immune system. They filter harmful substances such as bacteria and viruses so that they don’t spread to other parts of your body. Lymph nodes are about the size of a pea, but …

Adenomyosis (pronounced “add-en-o-my-OH-sis”) is when tissue similar to the lining of your uterus (endometrium) starts to grow into the muscle wall of your uterus (myometrium). It causes your uterus to thicken and enlarge — sometimes, up to double or triple its usual size. Adenomyosis can cause painful periods, heavy or prolonged menstrual bleeding with clotting and abdominal/pelvic pain.

Frozen shoulder is a painful condition in which your shoulder movement becomes limited. Another name for frozen shoulder is adhesive capsulitis. Frozen shoulder occurs when the strong connective tissue surrounding your shoulder joint (called the shoulder joint capsule) becomes thick, stiff and inflamed. The joint capsule contains the ligaments that attach the top of your upper arm bone (humeral head) to your …

Acute sinusitis is a short-term sinus infection (sinusitis). Acute sinusitis symptoms may last a week to 10 days and often go away without medical treatment. Home care and over-the-counter (OTC) decongestants help ease acute sinusitis symptoms.  

HIV stands for human immunodeficiency virus. HIV infects and destroys cells of your immune system, making it hard to fight off other diseases. When HIV has severely weakened your immune system, it can lead to acquired immunodeficiency syndrome (AIDS). Because HIV works backward to insert its instructions into your DNA, it is called a retrovirus.

Hidradenitis suppurativa (HS) is a condition that causes painful, recurring boils in areas of your body with sweat glands. There isn’t a cure, but treatment can help manage symptoms and prevent new boils and scarring. Another name for HS is acne inversa.

Acne is a common skin condition where the pores of your skin clog. Pore blockages produce blackheads, whiteheads and other types of pimples. Pimples are pus-filled, sometimes painful, bumps on your skin. The medical term for acne is acne vulgaris.

Reflux (acid reflux) is when food from your baby’s stomach travels back up into their esophagus. This may lead to spitting up and/or vomiting. In most babies, acid reflux isn’t problematic. It happens because your baby’s digestive tract isn’t fully mature yet. Your baby might spit up a lot — even daily — but have no health issues. Healthcare providers call such babies “happy spitters.” …

Achalasia is a rare disorder in which your esophagus is unable to move food and liquids down into your stomach. Your esophagus is the muscular tube that transports food from your mouth to your stomach. At the area where your esophagus meets your stomach is a ring of muscle called the lower esophageal sphincter (LES). This muscle relaxes (opens) to …