Drug-Induced Lupus Erythematosus

Background

Drug-induced lupus erythematosus (DILE) is a variant of lupus erythematosus that resolves within days to months after withdrawal of the culprit drug in a patient with no underlying immune system dysfunction. DILE can arise months to years after exposure to drugs prescribed to treat various medical conditions (eg, antihypertensives, antibiotics, anticonvulsants). The most common drugs that cause DILE are hydralazine, procainamide, quinidine, isoniazid, diltiazem, targeted immunotherapy, and minocycline.^[1]

Drug-induced subacute cutaneous lupus erythematosus (DISCLE) is a DILE variant with predominant skin involvement, temporally related to drug exposure, and resolving after drug discontinuation.^[2] It has been seen in association with hydrochlorothiazide, terbinafine, and leflunomide.^{[3, 4]}

Care must be taken to correctly diagnose the symptoms of DILE and differentiate it from systemic lupus erythematosus (SLE), and DILE should be recognized clinically and serologically for prompt intervention.

Although both SLE and DILE are autoimmune disorders and can have similar clinical and laboratory features (see the Table below), research suggests different mechanistic pathways. Although the pathogenesis of DILE is not completely understood, a genetic predisposition may play a role, as has been shown with certain drugs metabolized by acetylation, such as procainamide or hydralazine.^[5]

Table. Comparison of Findings Between Drug-Induced Lupus Erythematosus and Systemic Lupus Erythematosus

View Table

See Table

A large systematic review of 117 DISCLE cases demonstrated that White women made up the large majority of cases, and the mean age was 58 years. Antihypertensives and antifungals were most frequently the culprits. Time intervals between drug exposure and appearance of DISCLE varied and were drug-class dependent. Most cases resolved within weeks of drug withdrawal. No significant differences in the clinical, histopathological, or immunopathological features between DISCLE and idiopathic SCLE were detected.^[6]

Varying mechanisms leading to the formation of self-recognizing antibodies may explain the differential characteristics of drug effects in persons with DILE and those with SLE. For example, whereas some drugs can cause DILE, others may cause a flare of preexisting SLE.

Drugs such as procainamide, chlorpromazine, and quinidine cause the production of antinuclear antibodies against the histone dimer H2A-H2B. Hydralazine forms antinuclear antibodies to H1 and the H3-H4 complex.^[7] Drugs that cause DILE usually take months to years before the associated symptoms occur, whereas flares of SLE due to drugs may occur within hours to days. Serositis may be prominent.^[8]

Most patients with DILE have one or more clinical symptoms of SLE, such as arthralgias, lymphadenopathy, rash, and fever, and have had no prior history of autoimmune disease. However, certain manifestations typical in persons with SLE are not usually observed in persons with DILE.

No specific criteria establish the diagnosis of DILE, and excluding underlying autoimmune disease is not a simple process. DILE is typically diagnosed by a process of elimination to rule out SLE.

Symptoms of DILE usually clear within weeks of stopping the culprit drug. Generally, no other specific treatments are known. Low doses of systemic corticosteroids may be prescribed for short periods if the symptoms are severe.

• References

Pathophysiology

SLE and DILE are both autoimmune diseases that cause the immune system to manufacture autoantibodies against the patient’s own tissues. Molecular mimicry between antibodies directed against infectious agents (eg, bacteria, Epstein-Barr virus [EBV]) and self-antigens has been implicated in SLE. These theories hold that in SLE, the immune system generates autoantibodies to foreign antigens, and these autoantibodies, in turn, attack the patient’s own tissues.

In DILE, autoantibodies are thought to be generated by a mechanism other than molecular mimicry. The medications and other exposures implicated in DILE and flares of SLE produce autoantibodies more often than systemic autoimmune symptoms. Despite these commonalities, research suggests that DILE and SLE have separate and distinct mechanistic pathways. Which drug characteristics cause the autoantibody formation is unclear, but several theories have been proposed.

One is that the metabolites of the drug are subjected to oxidative metabolism and serve as a substrate for myeloperoxidase, which is activated in polymorphonuclear neutrophils. This interaction causes the formation of reactive metabolites that directly affect lymphocyte function in the thymus, disrupting central T-cell tolerance to the patient’s own tissues and producing autoimmune T cells against them. Both mouse models and human studies implicate thymic activity, possibly indicating the persistence of thymic activity into advanced adult life.

Virtually all lupus-inducing drugs undergo oxidative metabolism, whereas analogous non–lupus-inducing drugs do not. In a mouse model, reactive metabolites of procainamide injected into the thymus have been shown to result in lupuslike autoantibodies. Unlike drug hypersensitivity reactions, this process takes months to years of drug exposure for symptoms to develop.

A second theory is that with decreased T-cell methylation, an overexpression of lymphocyte function–associated antigen (LFA-1) occurs. T cells with hypomethylated DNA become autoreactive and cause antibody formation. This is the mechanism by which ultraviolet (UV) light causes flares of lupus.

A third theory is that the genetic differences in an individual’s P450 system causes drugs to be metabolized differently, which results in the generation of toxic metabolites that may facilitate autoimmunity.

Predisposing factors to the development of DILE include a slow drug-acetylator phenotype and advancing patient age. Slower acetylation may play a role in the greater predisposition for elderly persons to develop DILE.^[5] However, the higher rates of DILE in elderly persons are also likely to be due to decreased drug clearance and increased medication usage in these individuals.

Biologics such as interleukins (eg, interleukin-2 [IL-2]), interferons (eg, alfa, gamma, beta), and tumor necrosis factor alpha (TNF-α) inhibitors are associated with musculoskeletal symptoms and antibody production suggestive of a lupuslike autoimmune disorder. In 1 study, approximately 14% of rheumatoid arthritis patients treated with anti–TNF-α developed anti-DNA antibodies, whereas fewer than 1% developed lupuslike symptoms.

Recognition of DILE in patients receiving anti–TNF-α agents can be difficult.^[9] Making the diagnosis of DILE is even more challenging because cutaneous reactions with and without evidence of autoimmunity are very common in patients treated with anti–TNF-α drugs. It is particularly important to understand the temporal relationship between the onset of symptoms and the initiation of the medication, which can range from weeks to months.

A review by Ramos-Casals et al described 105 patients who developed DILE after starting anti–TNF-α therapy; in this group, lupuslike symptoms appeared at a mean time of 41 weeks after the initiation of anti–TNF-α therapy.^[10]

As TNF-α–targeted therapies are being used for an expanding number of autoimmune diseases, the number of reports of their induction of lupuslike syndromes has been growing. When one considers the large number of patients now treated with these biologic agents, the incidence of anti–TNF-α–induced DILE is relatively low.^[11] Most case reports have involved the use of etanercept or infliximab. Adalimumab is less often the inciting agent; this may simply be the result of fewer cumulative patient years of exposure to adalimumab.

In a report of 33 cases of anti–TNF-α agents causing DILE, Costa et al found that 21 were due to infliximab, 10 to etanercept, and only 2 to adalimumab.^[12] Of the 33 patients, 19 had only cutaneous manifestations. Anti–TNF-α agents induce a higher prevalence of antibodies to double-stranded DNA, hypocomplementemia, a higher incidence of both cutaneous and systemic disease, particularly renal involvement, than classic DILE caused by other drugs. Serositis may be clinically significant.^[13]

Cutaneous findings in TNF-α–associated DILE commonly include photosensitivity and the classic cutaneous findings associated with discoid lupus erythematosus and subacute cutaneous lupus erythematosus. Cutaneous manifestations are more frequently observed in patients receiving etanercept, whereas infliximab causes a higher incidence of serositis.

Fever is found in similar incidence in both TNF-α inhibitor–induced DILE and DILE caused by other categories of medications. More than 50% of laboratory results in anti–TNF-α–induced DILE patients show low serum complement levels and anti-dsDNA antibodies, which are usually absent or rare findings in classic DILE.

The use of anti–TNF-α agents is also associated with the emergence of other autoantibodies, such as anticardiolipin antibodies. Classic DILE is more often associated with antihistone antibodies. DeBandt looked at the only case of thrombosis in a patient with anticardiolipin antibodies and anti–TNF-α–induced DILE, although half of the anti–TNF-α–related DILE patients studied (12) had anticardiolipin antibodies.^[14]

The mechanism by which anti–TNF-α therapy induces DILE is not understood. One hypothesis is that the binding of the anti–TNF-α drug to the cell surface TNF-α induces cell apoptosis, which causes the release of antinucleosomal autoantigens and the induction of anti-dsDNA antibodies.^[12]

A second hypothesis is that the suppression of T-helper type 1 response from the anti–TNF-α therapy would generate an exuberant T-helper 2 response, leading to an overproduction of autoantibodies.^[15]

A third suggestion regarding the pathogenesis of DILE from these immunosuppressive agents is that patients on these medications may experience more bacterial infections, which are powerful stimulants that boost polyclonal B-lymphocyte activation and autoantibody production.^[16]

A baseline evaluation, including serology to rule out lupus erythematosus, should be considered in patients before the initiation of TNF-α therapy.^[12] A study demonstrated that the development of DILE after one TNF-alpha antagonist does not preclude continued treatment with an alternative TNF-alpha antagonist.^[17]

• References

Etiology

DILE may be induced by medications or caused by other compounds in the environment. The most common drugs that cause drug-induced SLE are hydralazine (rate roughly 20%), procainamide (rate roughly 20%, 5-8% if taken for 1 y), quinine, isoniazid, and minocycline.

Drugs most commonly associated with drug-induced SCLE include calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, thiazide diuretics, and TNF-alpha antagonists.^[17]

Several broad drug categories have been linked to DILE, including those described below.

Antacids

Histamine H2 receptor antagonists include the following:

• Ranitidine (discontinued)^{[6, 18]}

Proton pump inhibitors include the following^{[18, 19]} :

• Esomeprazole^{[18, 3, 20]}
• Lansoprazole^{[3, 6, 11, 18, 21]}
• Omeprazole (SCLE) (DISCLE)^{[3, 18, 22]}
• Pantoprazole^{[3, 18, 21]}

Antiarrhythmics

Antiarrhythmics include the following:

• Amiodarone^[23]
• Disopyramide^{[9, 11]}
• Procainamide^{[1, 2, 5, 9, 11]}
• Propafenone^{[9, 11]}
• Tocainide^[2]
• Quinidine^{[1, 2, 9, 11]}

Antibiotics

Antibiotics include the following:

• Amoxicillin + clavulanic acid^{[2, 18, 24]}
• Cefepime^[25]
• Ciprofloxacin^{[2, 18]}
• Doxycycline^{[2, 26]}
• Isoniazid^{[2, 9, 11]}
• Minocycline^{[2, 9, 11, 27, 28]}
• Nitrofurantoin^{[3, 9, 11]}
• Norfloxacin^[3]
• Para-amino-salicylic acid^[2]
• Penicillin^[2]
• Rifabutin^[29]
• Rifampin^[2]
• Rifamycin^[30]
• Streptomycin^[2]
• Tetracycline^[2]

Anticoagulants

Anticoagulants include the following:

• Ticlopidine^{[3, 6, 11, 21]}

Anticonvulsants

Anticonvulsants include the following:

• Carbamazepine^{[2, 3, 6, 9, 11, 31]}
• Diphenylhydantoin^[2]
• Ethosuximide^{[2, 9, 11]}
• Lamotrigine^{[3, 32, 33]}
• Phenytoin^{[2, 3, 6, 9, 11]}
• Primidone^{[2, 9, 11]}
• Trimethadione^{[2, 9, 11]}
• Valproate^[2]
• Zonisamide^[2]

Antidepressants

Antidepressants include the following:

• Bupropion^{[3, 6, 11, 21]}
• Citalopram^[3]
• Lithium^[2]
• Phenelzine^{[9, 11]}
• Sertraline^[34]

Antifungals

Antifungals include the following:

• Griseofulvin^{[2, 3, 6, 11, 21]}
• Terbinafine^{[2, 3, 6, 11, 21, 35]}

Antihistamines

Antihistamines include the following:

• Brompheniramine^{[3, 6, 18]}
• Cinnarizine + thiethylperazine^{[3, 6, 18]}

Antihypertensives

Antihypertensives include the following:

• Clonidine^{[2, 9, 11]}
• Methyldopa^{[2, 9, 11]}
• Olmesartan^[36]
• Reserpine^[2]

ACE inhibitors include the following^[37] :

• Captopril^{[2, 3, 6, 9, 11, 18]}
• Cilazapril^{[3, 6, 11, 18, 21]}
• Enalapril^{[3, 6, 9, 11, 18, 24]}
• Lisinopril^{[2, 3, 18]}
• Ramipril^{[3, 18, 24]}

Beta-blockers include the following:

• Acebutolol^{[2, 3, 6, 9, 11, 18, 21]}
• Atenolol^{[2, 9, 38]}
• Labetalol^{[2, 9, 11]}
• Metoprolol^[2]
• Ophthalmic timolol^{[2, 9]}
• Oxprenolol^{[3, 6]}
• Pindolol^{[2, 9, 11]}
• Prazosin^{[9, 11]}
• Propranolol^[2]

Calcium channel blockers include the following:

• Amlodipine^[3]
• Diltiazem^{[1, 3, 6, 11, 21, 39]}
• Nifedipine^{[3, 6, 11, 21]}
• Nitrendipine^{[3, 6, 21, 24]}
• Verapamil^{[3, 6, 11, 21]}

Diuretics include the following:

• Chlorothiazide^{[3, 6]}
• Chlorthalidone^{[9, 11]}
• Hydrochlorothiazide + triamterene^{[3, 6]}
• Hydrochlorothiazide^{[2, 3, 6, 9, 11, 18, 21]}
• Spironolactone (DISCLE)^[3]

Vasodilators include the following:

• Hydralazine^{[1, 2, 5, 8, 9, 11, 39]}
• Minoxidil^{[9, 11]}

Anti-inflammatories

Antirheumatics include the following:

• Penicillamine^{[2, 9, 11, 40]}

NSAIDs include the following:

• Aspirin^[41]
• Naproxen^{[3, 6, 11, 18, 21]}
• Piroxicam^{[3, 6, 11, 18, 21, 24]}
• Phenylbutazone^{[2, 9, 11]}
• Sulfasalazine^{[2, 9, 11, 40]}

Antipsychotics

Antipsychotics include the following:

• Chlorpromazine^{[2, 9, 11]}
• Chlorprothixene^{[9, 11]}
• Lithium carbonate^{[9, 11]}

Antithyroid agents

Antithyroid agents include the following:

• Iodine I 131^[3]
• Methimazole (bullous SLE)^{[2, 42]}
• Propylthiouracil^{[2, 9]}
• Thiamazole^[2]

Benzodiazepines

Benzodiazepines include the following^[41] :

• Clobazam^[2]
• Clozapine^{[2, 43]}

Biologics

Biologics include the following:

• Abatacept^[18]
• Bevacizumab^[3]
• Efalizumab^{[3, 6, 11, 21]}
• Golimumab (SCLE)^{[3, 44]}
• Interferons (alpha, beta, gamma)^{[2, 3, 6, 9, 11, 15, 21, 45]}
• Interleukins (IL-2)^{[2, 11]}
• Ranibizumab^[3]
• Rituximab^{[3, 46]}
• Secukinumab^[18]
• Ustekinumab^[18]

TNF-alpha inhibitors include the following^{[10, 11, 12, 14, 16, 17, 21, 46, 47, 48]} :

• Adalimumab^{[3, 11, 12, 13, 21, 48]}
• Etanercept^{[2, 3, 6, 11, 12, 21, 24]}
• Infliximab^{[2, 3, 9, 11, 12, 21, 48]}

Checkpoint inhibitors include the following:

• Ipilimumab^{[49, 50]}
• Nivolumab^{[1, 49, 50]}

Chemotherapy agents

Chemotherapy agents include the following:

• Anastrozole^{[2, 6, 18]}
• Atezolizumab^[1]
• Capecitabine^{[3, 6, 51]}
• Doxorubicin (DISCLE)^{[3, 18, 37]}
• Doxorubicin + cyclophosphamide^{[3, 37]}
• Gemcitabine^{[3, 18, 52, 51]}
• Hydroxyurea^[2]
• Imiquimod (DISCLE)^{[3, 18]}
• Masitinib^[18]
• Mitotane^{[3, 18]}
• Nivolumab^{[1, 18]}
• Palbociclib^[18]
• Pazopanib^[3]
• Pembrolizumab^{[1, 18]}
• Tamoxifen^{[3, 6, 11, 18, 21]}

Fluorouracil agents include the following:

• Fluorouracil^{[2, 3, 18, 53]}
• Tegafur^[2]
• Uracil-tegafur^{[2, 18]}

Taxanes include the following^[51] :

• Cabazitaxel (DISCLE)^[54]
• Docetaxel^{[3, 6, 18, 21, 37, 54, 51]}
• Paclitaxel^{[3, 6, 51]}

Cholesterol-lowering agents

Cholesterol-lowering agents include the following:

• Atorvastatin^[11]
• Fluvastatin^{[2, 11]}
• Gemfibrozil^[2]
• Lovastatin^{[2, 9, 11]}
• Pravastatin^{[3, 6, 11]}
• Simvastatin^{[2, 3, 6, 11]}

Hormonal therapy

Hormonal therapies include the following:

• Aminoglutethimide^[9]
• Estrogens^[2]
• Leuprolide acetate^{[2, 6]}
• Oral contraceptives^[2]

Immunomodulators

Immunomodulators include the following:

• Hydroxychloroquine^{[3, 24]}
• Leflunomide^{[3, 6, 11, 21, 24, 4]}

Inhalers

Inhalers include the following:

• Tiotropium bromide inhaler^{[3, 6, 55]}

Miscellaneous

Miscellaneous agents include the following:

• Allopurinol^{[2, 18, 24]}
• Hay with fertilizer^[6]
• Intravenous immunoglobulin^[18]
• Levodopa^[9]
• Lipstick^[6]
• Ultraviolet light therapy^{[3, 6]}
• Zafirlukast^[2]

Sulfonylureas

Sulfonylureas include the following:

• Glyburide (DISCLE)^[3]

Gold salts^[2]  and stool softeners^[18]  have also been linked to DILE.

A genetic predisposition may play a role. DILE has been observed with increased frequency in association with human leukocyte antigen (HLA)‒DR4.

Intrinsic genetic susceptibility may help explain why some patients experience DILE as a reaction to drug therapies, whereas others do not. For example, the rate of acetylation is genetically predetermined. In the United States, the population is almost evenly divided between those who are fast and those who are slow acetylators. Those with slow rates have a higher prevalence of DILE than those with faster rates. In contrast, SLE affects individuals with slow and fast rates approximately equally.

Other causes may induce DILE in certain individuals for no apparent reason, such as sensitivity to the following:

• Insecticide compounds
• Certain metallic compounds
• Fluorescent acid dye found in some lipsticks

Drugs that cause flares of SLE are as follows:

• Cimetidine
• Golimumab^[44]
• Hydralazine
• Hydrochlorothiazide
• Mesantoin
• Omeprazole^[22]
• Para-aminobenzoic acid (PABA)
• Penicillin
• Phenylbutazone
• Sulfonamides
• Terbinafine^[35]

• References

Epidemiology

As many as 10% of the approximately 500,000 cases of lupus erythematosus in the United States may be DILE. Patients with DILE tend to be older (50-70 y) than those with SLE (average age 29 y at diagnosis). Elderly persons generally are more susceptible to DILE.

DILE occurs less frequently in children than in adults. A review by Kaya Akca et al found that in children, the most frequently implicated drugs were ethosuximide and minocycline.^[56]

In DILE, no significant statistical difference is apparent in the prevalence for males versus females. In contrast, SLE affects women with considerably higher frequency than men (female-to-male ratio of 9:1). More Whites than Blacks develop DILE; more Blacks than Whites present with SLE.

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Prognosis

Prognosis is excellent once the causative medication is discontinued. Recovery generally occurs within days or weeks.

Death from DILE is extremely rare and may result from renal involvement. In diagnosing this condition, it is extremely crucial to first exclude the possibility that the patient has renal idiopathic lupus rather than DILE with renal involvement.

Complications

Although both SLE and DILE can affect multiple organ systems, including the skin, joints, kidneys, eyes, and CNS, complications of DILE that affect the kidneys and CNS are generally considered rare. In DILE induced by certain drugs, however, the rate of kidney involvement can be significant. For example, the rate of glomerulonephritis in hydralazine-induced DILE is 5-10%. In rare instances, patients may die of renal involvement.

Penicillamine is also more likely to be associated with renal disease. Rare cases of death associated with DILE have been reported as a direct result of renal complications. Thus, a renal biopsy may be necessary to rule out membranous proliferative and necrotizing glomerulonephritis. Hepatic necrosis is another potential serious complication of DILE and has been documented in cases of minocycline-induced DILE.

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History

Most patients with drug-induced lupus erythematosus (DILE) have 1 or more clinical symptoms of systemic lupus erythematous (SLE), such as arthralgias, lymphadenopathy, rash, and fever, and have no prior history of autoimmune disease. If a rash is present, it often manifests as a polycyclic, scaling, erythematous rash in sun-exposed areas.

Approximately 50% of patients have constitutional symptoms of fever, weight loss, and fatigue. As many as 90% of patients with DILE have severe but usually noninflammatory joint pain; however, synovitis may be present. Arthralgia is often the only clinical manifestation of DILE. As many as 50% of patients with DILE experience muscle pain (myalgia).

The drug will have been taken anywhere from 3 weeks to 2 years before the appearance of symptoms. Note that drug-associated exacerbations of SLE and typical drug hypersensitivities can also be temporally related to drug exposure. Clinical improvement is usually rapid when the drug is discontinued, whereas antinuclear antibodies and other serologic markers slowly decrease toward more normal levels.

Generally, the absence of central nervous system (CNS) and renal involvement is more suggestive of DILE than of SLE. High rates (ie, 5-10%) of glomerulonephritis, however, occur in hydralazine-induced DILE, and rare cases of death from renal involvement in DILE have been reported.

DISCLE differs from idiopathic SCLE by virtue of distinctive cutaneous features, particularly the common widespread presentation (82% vs 6%) and the frequent occurrence of malar rash (45% vs 6%), vasculitic manifestations (45% vs 3%), and bullous and erythema multiforme–like lesions (45% vs 1%). Visceral manifestations are not seen in DISCLE.^[24]

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Physical Examination

Extracutaneous physical findings in DILE can include the following:

• Splenomegaly
• Hepatomegaly
• Inflammation of the serous membranes that surround the lungs and pleural cavity walls (pleurisy)
• Fever
• Inflammation of the fibroserous membranes that cover the heart and the initial part of the great vessels (ie, pericarditis)
• Cerebritis (rarely)
• Episcleritis (rarely)^[48]
• Nephritis (rarely)

Skin findings are apparent in approximately 25% of all patients diagnosed with DILE. Note, however, that certain manifestations typical in persons with SLE are not usually observed in persons with DILE. Patients with DILE (unlike patients with SLE) typically do not have the following:

• Mucosal ulcers
• Hair loss (alopecia)
• Circular (discoid) plaques
• Photosensitivity (with the exception of thiazide-induced subacute lupuslike syndrome)

Compared with patients who have SLE, patients with DILE present with a higher prevalence of the following:

• Purpura
• Erythema nodosum (painful nodules, usually on the extremities)
• Erythematous papules (typically on sun-exposed areas; see the image below)

  View Image

  Erythematous macules and papules are seen on face, upper chest, and arms in photodistribution.

   

  

   

Lymphadenopathy or Raynaud phenomenon is present in approximately 35-50% of patients with SLE but in fewer than 25% of those with DILE.

More than 75% of patients with SLE also have cutaneous findings, versus an average of less than 25% in patients with DILE. However, in both SLE and DILE, approximately 75% of patients have arthritis or arthralgia.

Patients with DILE less commonly present as drug-induced SCLE, exhibiting skin findings that are analogous to those manifested in patients with SCLE, such as erythematous annular polycyclic or papulosquamous lesions, but malar rash and vasculitic urticarial manifestations can rarely be observed.^[21]

• References

Antibody Assays

Test for the presence of antinuclear antibodies, which can appear in a homogeneous pattern in as many as 90% of patients with lupus erythematosus. In drug-induced lupus erythematosus (DILE), when anti-ssDNA and anti-dsDNA are measured, the prevalence of anti-ssDNA is higher. This is a major difference from systemic lupus erythematosus (SLE); in SLE, antibodies tend to attack double-stranded DNA.

Antinuclear antibodies with homogeneous patterns are produced by procainamide, isoniazid, timolol, hydralazine, and phenytoin. In contrast, speckled antinuclear antibody patterns are associated with anti-SSA/Ro antibodies, which can be produced in response to thiazide diuretics such as hydrochlorothiazide. A systematic review evidenced that anti-SSA/Ro antibodies are found in most patient with DISCLE (about 80% of cases), in whom antihistone antibodies are uncommonly found, and most remained positive after resolution of SCLE skin disease activity.^[6]

In persons with DILE, the antibodies also tend to attack histones (proteins typically found in cell nuclei). Antihistone antibodies are indicated by a homogeneous pattern of antinuclear antibodies. They are present in more than 75% of patients with DILE induced by hydralazine and procainamide. An example of an antihistone antibody that is often implicated in DILE is immunoglobulin G (IgG; anti-[H2A-H2B] DNA). Antihistone antibodies are much more likely to indicate DILE; however, they can also appear in as many as 50% of patients with SLE.

In persons with DILE, anti-Sm antibodies are rare. Complement levels are within the reference range, which is not usually the case in persons with SLE.

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Other Tests

Further tests in the workup of a patient with possible DILE are as follows.

A complete blood cell (CBC) count should be performed to evaluate for anemia, which is present in most patients with SLE but is rare in those with DILE. Blood urea nitrogen (BUN) and creatinine should be assessed. C3 and C4 levels should be measured. Complement levels are often reduced in persons with SLE, whereas they tend to not be reduced in persons with DILE.

Liver function tests to can be performed to evaluate for hepatic involvement. Urinalysis can be performed to evaluate for hematuria and proteinuria.

Use chest radiography to rule out pulmonary infiltrates. Use echocardiography, if indicated, to rule out pericarditis.

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Tissue Analysis and Histologic Findings

Skin biopsy may be indicated, as well as renal biopsy if renal involvement is suggested. Skin biopsy and direct immunofluorescence typically reveal findings that are indistinguishable from those seen in SLE.

Histologic examination reveals variable epidermal atrophy, basal vacuolar degeneration, apoptotic or dyskeratotic keratinocytes, and lymphocytic interface dermatitis (see the images below).

View Image

Dermis contains interface and superficial and deep perivascular lymphohistiocytic infiltrate (×100, hematoxylin-eosin).

View Image

Parakeratosis, apoptosis, and basal vacuolization (×200, hematoxylin-eosin).

Direct immunofluorescence may reveal granular deposition of IgG along the dermoepidermal junction.

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Medical Care

Symptoms of drug-induced lupus erythematosus (DILE) usually clear within weeks of stopping the culprit drug; however, residual antibodies may persist for extended periods after discontinuance of the identified causative agent. Generally, no other specific treatments are known.

Hydroxychloroquine has been reported both as a causative agent of DILE in some patients^[3] and as an oral treatment of DILE for others.^{[18, 24]} Since administration of hydroxychloroquine presents a risk for exacerbating the symptoms of DILE, it is advised to focus treatment primarily through the discontinuation of the offending drug, and, if possible, prevent the introduction of new medications that could lead to a reoccurrence of DILE.

If patients with DILE are given anti-inflammatory medication, this may mask the symptoms and thus potentially result in misdiagnosis. Low doses of systemic corticosteroids may be prescribed for short periods if the symptoms of DILE are severe (eg, polyarthritis resulting in debilitating inflammation in many joints simultaneously).

No specific activity restrictions are recommended. Normal activity may resume when arthralgias and myalgias resolve.

Monitor antinuclear antibody levels—anti-ssDNA, anti-dsDNA, and antihistone antibody levels—serum complement levels, and urinalysis findings. Continue to monitor cardiac, renal, and pulmonary function if any of these were initially involved.

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Medication Summary

Symptoms of drug-induced lupus erythematosus (DILE) usually clear within weeks of stopping the culprit drug; however, residual antibodies may persist for extended periods after discontinuance of the identified causative agent. Generally, no other specific treatments are known.

Low doses of systemic corticosteroids may be prescribed for short periods if the symptoms of DILE are severe (eg, polyarthritis resulting in debilitating inflammation in many joints simultaneously).

• References

Methylprednisolone (A-Methapred, DepoMedrol, Medrol)

• Dosing, Interactions, etc.

Clinical Context:  Methylprednisolone is used as an anti-inflammatory or immunosuppressant agent in the treatement of a variety of diseases.

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Prednisone (Deltasone, Prednisone Intensol, Rayos)

• Dosing, Interactions, etc.

Clinical Context:  Prednisone is commonly used to treat inflammatory manifestations.

• References

Class Summary

Low doses of systemic corticosteroids may be prescribed for short periods if the symptoms of DILE are severe (eg, polyarthritis resulting in debilitating inflammation in many joints simultaneously).

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