Hajj, the journey to the Sacred Mosque in Mecca, is a once in a lifetime obligation for all adult Muslims who are physically and financially able. Each year, more than two million people globally, including more than 20,000 Britons take part in the Hajj.
Heat exhaustion and heat stroke are important hazards, write Abdul Rashid Gatrad and Aziz Sheikh. Even when Hajj occurs during winter, the average temperature is over 30°C during the day and 20°C at night.
"Men are particularly at risk, as they are prohibited from directly covering their heads during Hajj," says Professor Gatrad of Manor Hospital, Walsall. He recommends simple measures, such as use of an umbrella, preferably white in colour, to deflect the sun away.
"The risk of infectious diseases is also important," says Professor Sheikh of the University of Edinburgh. "Outbreaks of meningococcal meningitis occurred among British pilgrims in 1987, 2000, and 2001, and the Saudi authorities now insist that all pilgrims must be vaccinated."
Pilgrims also need to be aware of the risks of important bloodborne infections such as HIV and hepatitis B and C, especially as one of the rites of Hajj is for men to have their head shaved.
"With sensible precautions, most of these problems should be preventable," say the authors. The need for vaccination means that a "Hajj travel consultation" is now mandatory, and is an ideal opportunity for health professionals to offer general health advice.
In patients who have returned from Hajj, doctors should be vigilant for signs of diseases such as meningitis, tuberculosis, malaria, and hepatitis, they conclude.