Types of Lupus
There are four types of lupus: discoid, subacute cutaneous, systemic, and drug-induced.
Discoid
(cutaneous) lupus is always limited to the skin. It is identified by a rash
that may appear on the face in a butterfly
distribution (see photo) and also the neck and scalp. Discoid lupus is diagnosed by
examining a biopsy of the rash. In discoid lupus the biopsy will show
abnormalities that are not found in skin without the rash. Discoid lupus does
not generally involve the body's internal organs. Therefore, the ANA test, a
blood test used to detect systemic lupus, may be negative in patients with
discoid lupus. However, in a large number of patients with discoid lupus, the
ANA test is positive, but at a low level or "titer."
In approximately 10 percent of patients, discoid lupus can evolve into the
systemic form of the disease, which can affect almost any organ or system of
the body. This cannot be predicted or prevented. Treatment of discoid lupus
will not prevent its progression to the systemic form. Individuals who
progress to the systemic form probably had systemic lupus at the outset, with
the discoid rash as their main symptom.
Subacute
Cutaneous lupus
is
characterized by a non-scarring, erythematosus (red), coin-shaped lesion (see
photo) which
is very photosensitive (gets worse when exposed to UV light). This type of
lesion, which is characteristic of subacute cutaneous lupus, occurs in lupus
patients who, approximately 50% of the time, demonstrate features of systemic
lupus erythematosus. Renal disease, however, is unusual in these patients.
These skin lesions also occur in people who only have clinical evidence of
skin disease, and do not show any symptoms of systemic lupus. The subacute
cutaneous lupus lesions can sometimes mimic the lesions of psoriasis or they
can appear as non-scarring, coin-shaped lesions. These lesions can occur on
the face in a butterfly distribution, or can cover large areas of the
body.
Unlike
the discoid lupus lesions, these lesions do not produce permanent scarring,
but can be of major cosmetic significance. Lesions of subacute cutaneous lupus
may also be seen as a feature of neonatal lupus syndrome. Infants with
neonatal lupus, born of mothers with anti-Ro (SSA) antibodies, may develop a
transient lupus rash that disappears by the time they reach 6 months of age.
At the present time, the best evidence suggests that the anti-Ro (SSA)
antibody is passed via the placenta to the fetus and plays a major role in
causing the characteristic lupus skin disease
Systemic lupus is usually more severe than discoid lupus, and can
affect almost any organ or system of the body. For some people, only the skin (see photo)
and joints will be involved. In others, the joints, lungs, kidneys, blood, or
other organs and/or tissues may be affected. Generally, no two people with
systemic lupus will have identical symptoms. Systemic lupus may include
periods in which few, if any, symptoms are evident ("remission") and
other times when the disease becomes more active ("flare"). Most
often when people mention "lupus," they are referring to the
systemic form of the disease.
Drug-induced lupus occurs after the use of certain prescribed drugs.
The symptoms of drug-induced lupus are similar to those of systemic lupus. The
drugs most commonly connected with drug-induced lupus are hydralazine (used to
treat high blood pressure or hypertension) and procainamide (used to treat
irregular heart rhythms). Drug induced lupus is more common in men who are
given these drugs more often. However, not everyone who takes these drugs will
develop drug-induced lupus. Only about 4 percent of the people who take these
drugs will develop the antibodies suggestive of lupus. Of those 4 percent,
only an extremely small number will develop overt drug-induced lupus. The
symptoms usually fade when the medications are discontinued.