Urticaria pigmentosa

Fig. 1. Typical MPCM (urticaria pigmentosa) is the most common form of cutaneous mastocytosis, a In adults, lesions consist of numerous small red-brown macules and slightly elevated disseminated papules, b In less obvious cases, however, lesions arefewor less well recognizable and may be overlooked. 

Maculopapular cutaneous mastocytosis/urticaria pigmentosa Subvariants... 

Hymenoptera venom is a prominent trigger of systemic reactions. Severe and fatal reactions have been described in patients with mastocytosis [9, 30, 31]. In few cases with urticaria pigmentosa and Hymenoptera venom anaphylaxis, no sensitization could be detected by means of skin tests and determination of specific IgE antibodies [32]. However, larger series found evidence that these systemic reactions are normally IgE-mediated insect sting allergies [7,33]. 

Simpson JK, Brockow K, Turner ML, et al Generalized erythematous macules and plaques associated with flushing, repeated syncope, and refractory anemia. J Am Acad Dermatol 2002 46 588-590. Caplan RM The natural course of urticaria pigmentosa. Arch Dermatol 1963 87 146-157. 

Histamine is formed by decarboxylation of the amino acid l -histidine, a reaction catalyzed in mammalian tissues by the enzyme histidine decarboxylase. Once formed, histamine is either stored or rapidly inactivated. Very little histamine is excreted unchanged. The major metabolic pathways involve conversion to /V-methylhistamine, methylimidazoleacetic acid, and imidazoleacetic acid (IAA). Certain neoplasms (systemic mastocytosis, urticaria pigmentosa, gastric carcinoid, and occasionally myelogenous leukemia) are associated with increased numbers of mast cells or basophils and with increased excretion of histamine and its metabolites. 

Numerous reports, which rely chiefly on histochemical tests, have indicated that in pathological states of skin, especially in inflammation and malignancies, there is an increase in the level of acid mucopolysaccharides. High mucopolysaccharide contents of biopsy skin sections were demonstrated in chronic lupus (MIO) and in some cases of venous edema (Zl)j in scleroderma, however, the mucopolysaccharide content of the affected skin was low (MIO). Skin lesions from patients with lupus erythematosus, dermatomyositis, lichen sclerosus et atro-phicus, and poikiloderma showed significant increases in material which was stained histochemically (S20). In two cases of urticaria pigmentosa, hyaluronic acid was found in the histologically abundant mast cells (II) injection of hyaluronidase into the involved skin areas apparently cured the patients. An increased concentration of acid mucopolysaccharides has been obseri ed in sun-damaged skin (G5, SI, S12, S18). 

II. Igarashi, Y., Saito, Y., and Aizawa, I., Mucopolysaccharides in skin diseases I. Treatment of urticaria pigmentosa with hyaluronidase. Tohoku J. Exptl. Med. 58, 305-309 (1953). 

On two occasions, a fixed drug eruption occurred on the arm of a 45-year-old woman after using dextromethorphan as an antitussive (SEDA-16, 79). Worsening of urticaria pigmentosa has been attributed to dextromethorphan (SEDA-21, 87). 

Sahn EE, Dermatology Times April, 5 (infant with urticaria pigmentosa)... 

Skin—urticaria pigmentosa affected focus 160t D 70-3 37-9 D... 

Birt, a. R., Hagen, P. and Zebrowski, E., Amino acid decarboxylases of urticaria pigmentosa mast cells. J. Invest. Dermatol. 37, 273 (1961). 

Birt, a. R. and Nickerson, M., Generalized flushing of the skin with urticaria pigmentosa. Arch, Dermatol. 80, 311 (1959). 

Bloom, G., Duner, H., Pernow, B., Winberg, J. and Zetterstrom, R., Spontaneous histamine shocks in urticaria pigmentosa, Acta paediat. Upps. 47, 152 (1958). 

Gardner, L. I. and Tice, A. A., Histamine and related compounds in urticaria pigmentosa analyses of tissues having mast-cell infiltration. Pediatrics 21, 805 (1958). 

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