Hello - thanks for asking your question.
Although I am an internal medicine physician, please see your primary
care physician for specific questions regarding any individual cases –
please do not use Google Answers as a substitute for medical advice.
I will be happy to answer factual medical questions.
As you know, dermatographism is a condition where lightly scratching
the skin raises wheals or welts. Histamine is released at the site,
causing the small blood vessels (capillaries) to dilate, producing
redness and localized swelling. It is part of the spectrum of
urticaria (i.e. a form of allergic reaction). There are several
approaches to treatment - you may want to discusses these options with
your personal physician.
1) Antihistamines
These are the primary medications used. Antihistamines can be either
first (Benedryl or Atarax) or second generation (Claritin, Zyrtec or
Allegra).
You may also be familiar with several heartburn medications such as
Zantac or Pepcid. They also block histamine - and in 10 to 15 percent
of patients when used in combination with the antihistamines above,
there is further improvement.
2) Doxepin
Doxepin (Sinequan) is both an antidepressant and an antihistamine that
blocks H1 and H2 receptors. Topical doxepin cream (Zonalon), 5
percent, may be useful for suppressing pruritus in patients with
limited numbers of urticarial lesions (1).
3) Steroids
Corticosteroids may cause dramatic improvement in patients with
chronic urticaria, but should only be used after a trial of maximal
doses of antihistamines. Typically 30 to 40 mg of prednisone per day
in a single early morning dose is effective in suppressing urticaria.
Many patients will require corticosteroids for several months which
can be associated with significant side effects. In addition, a
recurrence of urticaria may occur after discontinuation of therapy.
4) Ketotifen
The mast cell stabilizing agent ketotifen has been available for many
years in Canada, Europe, and Japan for the treatment of urticaria; it
is not available in the United States.
5) Leukotriene inhibitors
Studies have found that zileuton, zafirlukast, and montelukast are
useful in certain patients with urticaria. They can be discussed with
your personal physician.
6) Calcium channel blockers
Nifedipine has been used as an adjunctive agent in cases of refractory
urticaria. This class of drug potentially interferes with
calcium-dependent mast cell degranulation. (2)
7) Other agents
The antimalarials hydroxychloroquine and chloroquine, Dapsone, and
Sulfasalazine have been shown in small studies to have some
improvement in urticaria.
As you can see, there are many options available to treat the
dermatographism. These medications should be discussed with your
personal physician. An allergy referral should be considered for
further evaluation.
Regarding your question of serum IgA - this can be simply done via a
blood test that can measure IgA levels. To my knowledge, the IgA
level is not part of the normal evaluation for urticaria. IgE is a
possibility, but is normally limited to academic centers. This is
what UptoDate has to say about the laboratory workup:
"The history and physical examination should be used to guide the
laboratory work-up in most cases of acute and chronic urticaria.
Laboratory studies are typically normal in patients with acute
urticaria and are therefore generally not performed. In one study of
125 patients with chronic urticaria, abnormal routine laboratory or
radiographic studies were found in 26 cases (21 percent). The majority
of these abnormalities were evident from the initial history and
physical examination, although it was concluded that a CBC with
differential and erythrocyte sedimentation rate (ESR) were
cost-effective for most patients.
An elevated ESR should prompt further investigation for systemic
diseases, since urticaria alone does not usually increase the ESR.
Such an evaluation may include measurement of antinuclear antibodies
(ANA), thyroid peroxidase antibody, complement profile, cryoglobulins,
hepatitis B and C serologies, and a serum protein electrophoresis.
Evaluation for specific autoantibodies against IgE or FcepsilonRI is
restricted to research centers." (3)
This answer is not intended as and does not substitute for medical
advice - the information presented is for patient education only.
Please see your personal physician for further evaluation of your
individual case.
Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.
Thanks,
Kevin, M.D.
Search strategy:
No internet search engine was used in this answer. All sources are
from physician-written and peer-reviewed sources.
Bibliography:
1) Smith, PF, Corelli, RL. Doxepin in the management of pruritus
associated with allergic cutaneous reactions. Ann Pharmacother 1997;
31:633.
2) Bressler, RB, Sowell, K, Huston, DP. Therapy of chronic idiopathic
urticaria with nifedipine: Demonstration of beneficial effect in a
double-blinded, placebo-controlled, crossover trial. J Allergy Clin
Immunol 1989; 83:756.
3) Bingham. Etiology and diagnosis of urticaria. UptoDate, 2003.
4) Bingham. Treatment of urticaria. UptoDate, 2003. |
