Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Yukiko Tsuji-Abe and Hiroshi Shimizu
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Prurigo pigmentosa is a pruritic eruption, commencing with urticarial papules or papulovesicles on the nape, chest, and back, followed by a peculiar reticular pigmentation. The majority of reported patients are Japanese with a female preponderance, but non-Japanese patients are also described.
The pathogenesis of prurigo pigmentosa remains unknown. Friction from clothing in wet conditions such as sweating or swimming can trigger the disease. In some cases, ketosis caused by diabetes mellitus, sudden weight loss, or anorexia nervosa precedes prurigo pigmentosa, and treatment of these conditions can lead to lesion resolution. There are several case reports of individuals who developed this condition in association with other disorders, including contact allergic reactions to certain chemical agents, Helicobacter pylori infection, atopic diathesis, and pregnancy. Minocycline (100–200 mg daily) and dapsone (25–100 mg daily) are usually very effective for prurigo pigmentosa. The effects are mostly observed within a few days or a week after treatment, with a reduction in both itch and papular lesions. Minocycline is regarded as first-line therapy, because it produces fewer adverse reactions, and the remission time has been reported as being longer than with dapsone treatment. Topical or systemic corticosteroids or antihistamines are usually ineffective.
Urinalysis for ketones
Mitsuhashi Y, Suzuki N, Kawaguchi M, Kondo S. J Dermatol 2005; 32: 767–8.
Kubota Y, Koga T, Nakayama J. Eur J Dermatol 1998; 8: 439–41.
Oh YJ, Lee MH. J Eur Acad Dermatol Venereol 2012; 26: 1149-53.
Out of 10 cases, six patients were positive for urinary ketone tests. Of those, five cases were related to dieting or fasting. Two patients underwent retests after treatment, which were negative in both cases.
Nakada T, Sueki H, Iijima M. Clin Exp Dermatol 1998; 23: 25–7.
A young woman with anorexia nervosa developed prurigo pigmentosa. After she gained weight, the lesions resolved completely.
In all these reports, prurigo pigmentosa was associated with ketosis. Disease activity sometimes correlated with the amount of urinary ketones. In some cases, lesions resolved simply as a result of treating the causative condition.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
