Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Nina R. Farquharson and Robert J.G. Chalmers
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Subcorneal pustular dermatosis is a rare, chronic, neutrophilic dermatosis of unknown etiology, in which flaccid pustules and vesicopustules, classically resembling a hypopyon, arise in crops on truncal and flexural skin. The condition occurs at any age, more commonly in females, and usually follows a relapsing and remitting course, but generally the patient remains systemically well. Long-term follow-up is required because monoclonal IgA paraproteinemia or myeloma may occur many years after presentation. The condition may be difficult to differentiate from other vesicopustular dermatoses, and some cases may eventuate into pustular psoriasis. Immunofluorescence studies are required to differentiate it from IgA pemphigus (synonyms: intraepidermal IgA pustulosis, intercellular IgA dermatosis), which has an essentially identical clinical presentation but in which IgA class autoantibodies to desmosome components can be demonstrated.
Dapsone is the treatment of choice (25–200 mg daily) and normally results in resolution of the rash within 4 weeks; the drug usually needs to be continued long term because relapse is common on withdrawal of therapy. After control is gained, the dose should be tapered to the lowest dose required to maintain remission. Other sulfones (sulfapyridine, salazosulfapyridine) have also been found to be beneficial in isolated reports.
In a proportion of cases the response to dapsone is poor; retinoids (formerly etretinate, now replaced by acitretin) have been substituted with success, using an initial dose of 0.5–1.0 mg/kg daily and then reducing to the lowest dose that will maintain control. Alternatively, for those unable to tolerate dapsone in the dose required, retinoids have been added to dapsone; this has enabled lower doses of each to be used. There are a few case reports detailing good response to phototherapy – psoralen and UVA (PUVA), narrowband UVB, or broadband UVB – in combination with dapsone or retinoids.
Both topical and systemic corticosteroids have been reported in isolated cases to provide some degree of control. Unacceptably high doses of systemic corticosteroids may be required, but combination with dapsone, cyclosporine, vitamin E or tetracycline antibiotics (minocycline, tetracycline) may allow control with lower doses.
Subcorneal pustular dermatosis tends to run a chronic course. Maintenance of a continuing beneficial response may be difficult, as may be inferred from the extensive range of treatment options described. Although dapsone appears to offer the best chance of a good therapeutic response, treatment regimens for this condition have not been formally evaluated.
Full blood count
Immunoglobulin levels
Serum protein electrophoresis
Bence–Jones protein
Autoantibodies
Skin biopsy with immunofluorescence
Cheng S, Edmonds E, Ben-Gashir M, Yu RC. Clin Exp Dermatol 2008; 33: 229–33.
A useful review of current literature. The authors discuss the relationship between subcorneal IgA pemphigus and classical subcorneal pustular dermatosis and accept that several authorities now consider this former subgroup to be a rare variant of pemphigus.
Lutz ME, Daoud MS, McEvoy MT, Gibson LE. Cutis 1998; 61: 203–8.
Four of the seven patients in whom immunoglobulins were checked had paraproteinemia: three of IgA and one of IgG type; none of these patients had IgA deposits on direct immunofluorescence.
Kasha EE, Epinette WW. J Am Acad Dermatol 1988; 19: 854–8.
Vaccaro M, Cannavò SP, Guarneri F. Eur J Dermatol 1999; 9: 644–6.
A case report of IgA λ myeloma. Treatment of the underlying myeloma had no effect on the skin disease.
Butt A, Burge SM. Br J Dermatol 1995; 132: 313–15.
Useful overview of all reported cases associated with either seronegative or seropositive arthritis.
Subcorneal pustular dermatosis has also been reported in association with pyoderma gangrenosum, Crohn disease, ulcerative colitis, systemic lupus erythematosus, rheumatoid arthritis, morphea, myeloproliferative disorders, lymphoproliferative disorders, hyperthyroidism, multiple sclerosis, solid tumors, and infections, particularly Mycoplasma. Isolated reports detail resolution with treatment of the associated disorder. Two drugs have been implicated: diltiazem and thiols (bucillamine or gold sodium thiomalate). In one case the condition arose at the site of injection of recombinant human granulocyte-macrophage colony stimulating factor.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
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