General medical conditions

Use the search box to learn about general medical conditions that affect children and young people.

Click here for information about specialist medical conditions, which are treated at Great Ormond Street Hospital.


Lots of teenagers experience acne. It’s a very common skin condition among 12 to 15 year olds. It affects the hair follicles in your skin, mainly on the face, chest and back.


Anaemia is a very common condition where the number of red blood cells or the amount of haemoglobin in red blood cells is less than normal. Iron deficiency anaemia is a specific type of anaemia caused by a lack of the mineral iron in the body. Iron is important in the formation of haemoglobin so a reduced iron level causes a reduced haemoglobin level in the blood.


A birthmark is a mark on the skin that is either present at birth or develops in the first few weeks of life. Birthmarks are very common and most types do not require any treatment at all. This information sheet from Great Ormond Street Hospital (GOSH) describes the different types of birthmark that can occur, how they can be treated (if needed) and where to get help. 


A chalazion is a cyst (swollen area of tissue filled with fluid) that develops on the eyelid. The cyst is not usually painful, but can take a while to go down. Only very large chalazions can affect vision, by pressing on the eye.

Congenital curly toes

Congenital curly toes is a condition that is present at birth and tends to affect the third, fourth and fifth toes on one or both feet. This information from Great Ormond Street Hospital (GOSH) explains the causes, symptoms and treatments for the condition.


Conjunctivitis is a very common eye infection. It involves the inflammation (swelling) of the conjunctiva which is the thin delicate membrane that covers the whites of the eyes and lines the inside of the eyelids.


Croup is a common childhood condition that affects the upper part of the respiratory system – the trachea (windpipe), bronchi and larynx (voice box). It causes noisy breathing, a barking cough and sometimes a hoarse voice.