Urticaria pigmentosa is an eruption consisting of multiple collections of mast cells in the skin. Typically symmetrical, yellow-red papules and plaques with a tendency to cluster are seen in the skin. Bullae can develop.
Urtication can occur from minor trauma, secondary to histamine release.
A variant with a marked telangiectatic component is known as telangiectasia macularis eruptiva perstans.
Urticaria pigmentosa effects children and adults. In adults, it can take a very chronic course.
Mast cell leukemia also occurs.
- Avoidance of mast cell degranulating agents such as the morphine/codeine group and ASA is important.
- Antihistamines may be sometimes helpful.
- Avoidance of trauma is important.
- Oral ketotifen may be helpful in some patients, as is PUVA therapy.
- Solitary mastocytomas do not require treatment and clear spontaneously.
- Oral nifedipine can reduce the flushing seen in some patients with systemic mastocytosis.