DEAR DR. GOTT: I am a concerned grandmother writing about my 11-year-old granddaughter. She was diagnosed with porphyria at the age of two. Her hands and feet start hurting so badly that she has to put them in cold bath water for about an hour. She says it feels like needles running though her. She usually has a fan on her. Her hands also get very hard and cracked. Her nose is starting to scar from all the scratching because it itches. Lotion seems to evaporate. Any information you can provide would be greatly appreciated.

DEAR READER: Porphyria refers to a group of disorders that causes a buildup of porphyrins (one of the components that makes heme, which is needed to make hemoglobin). It is typically treated by a hematologist (blood specialist). There are eight types: Six are cutaneous (primarily affecting the skin), and two are acute (affecting the nervous system).

The exact prevalence of these conditions is unknown, but, according to the Genetic Home Reference (www.ghr.nlm.nih.gov), it is likely that the disease affects between 1-in-500 to 1-in-50,000 people worldwide. Porphyria cutanea tarda is the most prevalent form. Acute intermittent porphyria is the most common acute form in most countries. Some forms have no known prevalence because many people with the gene mutation associated with the disorder never manifest symptoms.

Cutaneous porphyria symptoms include itching, red urine, blisters, painful skin redness and swelling. Acute symptoms include fever, paranoia, vomiting, abdominal pain, diarrhea, constipation, confusion, hallucinations, high blood pressure, seizures, red urine, disorientation, muscle pain/tingling/numbness/weakness/paralysis, and pain in the arms, legs or back. Acute attacks are rare before puberty and after menopause. Cutaneous attacks can begin as early as infancy.

Most cases of porphyria are inherited; however, just having one of the genetic mutations responsible does not mean that the person will develop the disorder. In some cases, a trigger, such as smoking, infection, menstrual hormones, certain drugs, dieting/fasting, surgery, stress, alcohol use, sun exposure or excess iron in the body, starts the disorder in motion.

Treatment depends on the severity of symptoms, type of porphyria and more. Acute porphyria is treated primarily by eliminating symptoms with pain medication, IV fluids and glucose to combat dehydration, the maintenance of adequate carbohydrate intake, prompt treatment of infections, and injections of hemin or hematin, which help the body produce heme and reduce levels of porphyrins.

Cutaneous porphyria is treated primarily by reducing the level of porphyrins within the body. This can be achieved by phlebotomy (removing a certain amount of blood from the body, such as that done during donation or laboratory testing), oral-activated charcoal (to absorb the excess porphyrins) or daily beta-carotene (which may increase the skin's sun tolerance).

There are certain steps that sufferers can take to reduce the number of attacks they have, such as minimizing exposure to sunlight, using sunscreen and protective clothing whenever outside, reducing stress, avoiding smoking and alcohol, and treating infections and other illnesses promptly.

Family members of affected people should consider undergoing genetic testing to determine whether they carry the mutation. The disorder may never cause problems, but it can still be passed on to future generations, and it is possible that it could be triggered at any point.

Your granddaughter likely has a skin manifestation of the condition. She should be under the care of a pediatric hematologist familiar with the disorder.