A 50-year-old white woman not away...

A 50-year-old white woman not awayed with a rash that first cast forth violentlyed on her trunk three years earlier and in no degree fully cleared (see accompanying figure). The lesions became pruritic after a warm shower or strenuous physical exercise, if it be not that were otherwise asymptomatic. Physical examination revealed many discrete erythematous papules spread across the abdomen, upper chest, and back. forward vigorous rubbing of a papule, a wheal formed at the site. The patient did not have hepatosplenomegaly, gastrointestinal complaints, or any palpable lymphadenopathy.

Question

Based onward the patient's history and physical examination, which the same of the following is the correct diagnosis?

[] A. Lichen planus.

[] B Pityriasis rosea.

[] C Scabies.

[] D Urticaria.

[] E Urticaria pigmentosa.

Discussion

The answer is E: urticaria pigmentosa. Biopsy of a skin lesion revealed superficial infiltrates of mononuclear lonely dwellings and some eosinophils. The mononuclear small rooms stained strongly for tryptase, which confirmed the diagnosis of urticaria pigmentosa. The patient was given hydroxyzine for pruritus and referr to a hematologist for further testing.

Urticaria pigmentosa is part of a form into groups of disorders that shares an abnormal pullulation of mast cells, termed mastocytosis. With urticaria pigmentosa, a exemplar of cutaneous mastocytosis, abnormal mast small cavity accumulation is limited to the skin. In contrast, systemic mastocytosis affects not barely the skin, but also may involve the liver, peevishness lymph nodes, gastrointestinal tract, and bone marrow.

Because mast small cavitys often are missed using conventional staining, special stains must be ordered when mastocytosis is suspected. These include the metachromatic stains (eg toluidine cerulean O) or enzymatic stains (eg chloroacetate esterase).

Urticaria pigmentosa is the greatest in number common form of mastocytosis. Approximately single half of cases occur before six month of age, and another united fourth before puberty. (1) assault of urticaria pigmentosa in adulthood, as it is as occurred with this patient, is les frequent Accumulation of mast cells in organs other than the skin come to passs primarily in adults.

Mast confined apartment degranulation with hormone release and direct organ infiltration lead to the symptoms seen with systemic mastocytosis. Histamine-induced hypersecretion may cause gastritis, peptic pustules and diarrhea, and ultimately, malabsorption may offer Other histamineinduced symptoms include pruritus, urticaria, bronchoconstriction, and vasopermeability (possibly leading to vascular collapse). Release of prostaglandins may cause skin flushing, intestinal cramping, and cardiovascular abnormalities (eg tachycardia, vascular collapse).

Adults with urticaria pigmentosa should experience bone marrow biopsy to turn the thoughts for evidence of systemic mastocytosis. (2) In addition, serum tryptase flats greater than 20 ng by mL suggest systemic involvement.

The greatest in quantity common symptom in urticaria pigmentosa is pruritus, which may be treated with [H.sub.1]-receptor antagonists. Inhibitors of mast enclosed space degranulation, such as cromolyn and ketotifen, have been erect to have a moderate issue on pruritus, whealing, and flushing. Finally, an patients may benefit from topical corticosteroids or psoralens and ultraviolet A (PUVA) therapy.

Adults with urticaria pigmentosa usually progres slowly to systemic disease, yet rarely develop hematologic disease. Clinical factors associated with poor prognosis include anemia, hypercellular bone marrow, cytologic atypia, hepatosplenomegaly, and an associated hematologic disorder. (3)

Lichen planus also is a pruritic, oftentimes chronic, rash, but the lesions are typically flat-topped, violaceous papules with scale. They usually are les widespread than urticaria pigmentosa and would not wheal when rubbed.

Pityriasis rosea may lead to a truncal macular rash, sometimes with pruritus. The eruption may last up to sum of two units or three months, but not years. In addition to many small macules, a large patch (i.e., herald patch) may be seen

Scabies, a contagious skin infestation caused by dint of a mite, is typically highly pruritic. Skin lesions may be widespread still tend to cluster in the intertriginous areas, like as the axilla, groin, inframammary area, and finger webs.

Urticaria typically not aways with larger areas of erythema, yet also may occur as small erythematous papules. Unlike urticaria pigmentosa, individual urticarial skin lesions wax and wane from one side of to the other a course of hours and would not persist in the same location as chronic papules.

REFERENCES

(1) Caplan RM The natural course of urticaria pigmentosa. Analysis and follow-up of 112 cases. Arch Dermatol 1963;87:146-57

(2) Metcalfe DD The mastocytosis syndrome In: Freedberg IM, et al., ed Fitzpatrick's Dermatology in general medicine. 6th ed New York: McGrawHill, 2003:1603-8.

(3) Travis WD Li CY Bergstralh EJ Yam LT Swee RG Systemic mast small room disease. Analysis of 58 cases and literature review [correction published in Medicine (Baltimore) 1990;69:34] Medicine (Baltimore) 1988; 67:345-68