Urticaria Pigmentosa - Causes, Symptoms and Treatment

Definition

Urticaria pigmentosa is an uncommon rash that usually affects the neck, arms, legs and trunk of children and young adults. The rash consists of reddish-brown spots that turn into hives when they are rubbed hard or scratched. Sometimes the spots will blister. Urticaria Pigmentosa is the most common form of cutaneous mastocytosis. It is a rare disease caused by excessive amounts of mast cells in the skin that produce hives or lesions on the skin when irritated. Urticaria pigmentosa is most often seen in children, but it can occur in adults as well. Rubbing of a lesion produces a rapid wheal (a hive-like bump). Younger children may develop a fluid-filled blister over a lesion if it is scratched. A large histamine release from these extra mast cells may cause flushing, headache, diarrhea, a rapid heartbeat and even fainting. They can appear on any part of the body including the scalp, face, trunk and limbs.

Causes

1. Urticaria pigmentosa is one of several forms of mastocytosis which is caused by excessive numbers of inflammatory cells in the skin.
2. Urticaria pigmentosa is most often seen in children. So age is a risk factor included in this disease.
3. If it lesion scratched younger children may develop a fluid-filled blister over it.
4. A large histamine release from these extra mast cells may cause flushing, headache, diarrhea, a rapid heartbeat, and even fainting.
5. Consuming hot beverages, spicy foods, or alcohol may also make itching worse.

Symptoms

1. Red or brown spots are often seen on the skin, typically around the chest and forehead.
2. Rubbing or scratching the spots of urticaria pigmentosa may make the spots itch.
3. Itching may be worsened by changes in temperature, contact with clothing or other materials, or use of some drugs.
4. Affected sites may be bone, liver, spleen, lymph nodes or the gastrointestinal tract.
5. Urticaria pigmentosa may cause fever, weight loss, diarrhoea and abdominal pain.
6. Severe itching usually follows and scratching the area only serves to further symptoms. Symptoms can range from very mild to life-threatening.

Treatment

1. Avoidance of mast cell degranulating agents such as the morphine/codeine group and ASA is important.
2. Antihistamines may be sometimes helpful.
3. Oral nifedipine can reduce the flushing seen in some patients with systemic mastocytosis.
4. Paradoxically Low-dose aspirin can help some patients, but must be taken cautiously as aspirin can also worsen symptoms.
5. Photochemotherapy: This form of ultraviolet radiation is the most effective treatment for adults with urticaria pigmentosa. Two or three treatments each week are required for several months. PUVA lessens the itch and improves the appearance.
6. Interferon: This is the treatment used when the condition of disease is severe. It is an expensive treatment and is not very available. It is rare in practice.
7. Patients with urticaria pigmentosa should avoid aspirin, codeine, opiates, procaine, and alcohol. Polymyxin B, hot baths, and vigorous rubbing after bathing and showering.