Skip to Content

Aldara Side Effects

Generic Name: imiquimod topical

Note: This document contains side effect information about imiquimod topical. Some of the dosage forms listed on this page may not apply to the brand name Aldara.

For the Consumer

Applies to imiquimod topical: topical cream, topical kit

Along with its needed effects, imiquimod topical (the active ingredient contained in Aldara) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking imiquimod topical:

More common
  • Blisters on the skin
  • body aches or pain
  • chills
  • cough
  • difficulty with breathing
  • ear congestion
  • itching in the genital or other skin areas
  • loss of voice
  • open sores or scabs on the skin
  • pain or tenderness around the eyes and cheekbones
  • redness of the skin (severe)
  • scaling
  • shortness of breath or troubled breathing
  • skin rash
  • sneezing
  • sore throat
  • stuffy or runny nose
  • tightness of the chest or wheezing
  • unusual tiredness or weakness
Less common
  • Abdominal or stomach pain
  • ankle, knee, or great toe joint pain
  • bladder pain
  • bloody or cloudy urine
  • blurred vision
  • chest pain
  • cold flu-like symptoms
  • difficult, burning, or painful urination
  • dizziness
  • fainting
  • fast or irregular heartbeat
  • frequent urge to urinate
  • hoarseness
  • joint stiffness or swelling
  • lower back or side pain
  • lump in the abdomen or stomach
  • nervousness
  • persistent non-healing sore
  • pink growth on the skin
  • pounding in the ears
  • reddish patch or irritated area
  • severe headache
  • shiny bump on the skin
  • slow or fast heartbeat
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • white, yellow or waxy scar-like area
Incidence not known
  • Blue lips and fingernails
  • convulsions
  • coughing that sometimes produces a pink frothy sputum
  • dilated neck veins
  • extreme fatigue
  • fast, irregular, or pounding heartbeat
  • headache
  • irregular breathing
  • nausea or vomiting
  • pain in the shoulders, arms, jaw, or neck
  • slurred speech
  • sudden and severe inability to speak
  • suicide
  • sweating
  • swelling of the face, fingers, feet, or lower legs
  • temporary blindness
  • weakness in the arm or leg on one side of the body
  • weight gain

Get emergency help immediately if any of the following symptoms of overdose occur while taking imiquimod topical:

Symptoms of overdose
  • Confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

Some side effects of imiquimod topical may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Burning or stinging of the skin (mild)
  • flaking of the skin
  • mild headache
  • pain, soreness, or tenderness of the skin (mild)
  • rash
  • redness of the skin (mild)
  • swelling at place of application
Less common
  • Back pain
  • lightening of the treated skin

For Healthcare Professionals

Applies to imiquimod topical: topical cream


In general, the side effects associated with imiquimod topical (the active ingredient contained in Aldara) may vary depending on the condition being treated.[Ref]


Local skin reactions were recorded as adverse reactions only if they extended beyond the treatment area, if they required any medical intervention, or they resulted in patient discontinuation from a study.

In studies involving treatment of actinic keratosis or superficial basal cell carcinoma, the dermatologic side effects classified as local and application site most frequently resulted in clinical intervention (e.g., rest periods, withdrawal from study, treatment site infections requiring treatment with antibiotics).

Flaking/scaling was reported in 40% of males and 26% of females and scabbing/crusting was reported in 34% of males and 18% of females; otherwise, frequency and severity of local skin reactions were similar in both genders.[Ref]

Local side effects have included application site reaction (up to 33%), application site pain (up to 7%), application site irritation (up to 6%), application site pruritus (up to 4%), application site bleeding, application site swelling, treatment site infection, scarring, application site rash, application site cellulitis, and application site excoriation. Local skin reactions have included erythema (all grades: up to 100%; severe: up to 31%), scabbing/crusting (all grades: up to 93%; severe: up to 19%), flaking/scaling/dryness (all grades: up to 93%; severe: up to 8%), flaking/scaling (all grades: 91% ; severe: 4%), induration (all grades: up to 84% ; severe: up to 6%), edema (all grades: up to 78%; severe: up to 7%), erosion (all grades: up to 66% ; severe: up to 14%), erosion/ulceration (all grades: up to 62%; severe: up to 13%), exudate (all grades: up to 51%; severe: 6%), ulceration (all grades: up to 40% ; severe: up to 6%), weeping/exudate (all grades: up to 22%), vesicles (all grades: up to 31%; severe: up to 2%), excoriation/flaking (all grades: up to 26%; severe: up to 1%), and scabbing (all grades: up to 13%). Application site reactions have included itching (up to 20%), burning (6%), bleeding (up to 3%), stinging (3%), pain (3%), erythema (2%), papule(s) (2%), induration (2%), tenderness (up to 2%), irritation (2%), and infection (1%). Application site disorders reported in more than 1% of patients have included burning, hypopigmentation, rash, sensitivity, soreness, stinging, and tenderness. Itching (32% in females, 22% in males), burning (26% in females, 9% in males), pain (8% in females, 2% in males), and soreness (3% in females) were reported at the wart site. Tingling at the application site has been reported during postmarketing experience.[Ref]


Respiratory side effects have included upper respiratory tract infection (up to 15%), sinusitis (up to 7%), rhinitis (3%), coughing (2%), and pharyngitis (1%). Pulmonary congestion and bronchitis have been reported. Dyspnea and pulmonary edema have been reported during postmarketing experience.[Ref]


Immunologic side effects have included fungal infection (11% in females, 2% in males), herpes simplex (up to 3%), oral herpes (up to 3%), viral infection (1%), herpes zoster, and infection. Herpes simplex has also been reported during postmarketing experience.[Ref]

Nervous system

Two cases involving the development of chronic neuropathic pain following initiation of imiquimod topical (the active ingredient contained in Aldara) therapy for the treatment of warts have been reported. In the first case, a 53-year-old man with genital warts reported an erosion with substantial pain on the left lateral glans of the penis approximately 1 week following initiation of therapy with imiquimod applied topically 3 times a week. Imiquimod therapy was discontinued; however, the patient continued to report a burning-like pain and erythema in the area for approximately 2 years. The condition may have been exacerbated by aerobic exercise, sweating, and sexual activity. In the second case report, a 64-year-old woman with plantar warts developed numbness and pain in all toes and the balls of both feet following approximately 5 months of therapy with imiquimod topical applied each night with tape occlusion. Imiquimod topical was discontinued. This condition may have been exacerbated by a daily paring of the warts by the patient prior to imiquimod application. Approximately 2 years later, the patient reported a gradual improvement in the numbness and an absence of the burning-like pain. Neither patient had diabetes mellitus, or any other condition known to result in possible neuropathic pain.[Ref]

Nervous system side effects have included headache (up to 8%), dizziness (up to 3%), insomnia, and lethargy. Nervous system side effects have rarely included neuropathic pain. Agitation, convulsions (including febrile convulsions), insomnia, multiple sclerosis aggravation, and paresis have been reported during postmarketing experience.[Ref]


Other side effects have included back pain (up to 4%), fatigue (up to 4%), influenza-like illness (up to 4%), pyrexia (up to 3%), pain (up to 3%), influenza-like symptoms (3% in females, 1% in males), rigors (1%), and chills. Hernia, inflicted injury, and postoperative pain have been reported.[Ref]


Gastrointestinal side effects have included nausea (up to 4%), anorexia (up to 3%), diarrhea (up to 3%), dyspepsia (2%), cheilitis (up to 2%), and vomiting (up to 1%). Gastrointestinal disorder and aphthous ulcers (rare) have been reported. Abdominal pain has been reported during postmarketing experience.[Ref]

A review of 3 case reports involving patients receiving imiquimod topical applied 2 or 3 times weekly for treatment of actinic cheilitis in the lip region reported the formation of aphthous ulcers approximately 2 to 3 weeks following initiation of treatment. In each case, the aphthous ulcers resolved upon discontinuation of imiquimod topical and treatment with a topical steroid. None of the patients consented to a rechallenge.[Ref]


An 87-year-old Caucasian woman developed invasive amelanotic melanoma with satellite lesions within 14 weeks after initiation of treatment with imiquimod three times per week. It is unknown if this was a probable side effect of imiquimod or a progressive event of melanoma in situ.[Ref]

Oncologic side effects have included squamous cell carcinoma (up to 4%). Basal cell carcinoma has been reported. Oncologic side effects reported during non-FDA approved treatment of melanoma in situ have included a single case report of the development of invasive melanoma.[Ref]


Hematologic side effects have included lymphadenopathy (up to 3%) and pancytopenia. Decreases in red cell, white cell, and platelet counts (including idiopathic thrombocytopenic purpura), and lymphoma have been reported during postmarketing experience.[Ref]


Cardiovascular side effects have included chest pain (up to 2%), atrial fibrillation (1%), and hypertension. Capillary leak syndrome, cardiac failure, cardiomyopathy, cerebrovascular accident, arrhythmias (tachycardia, supraventricular tachycardia, atrial fibrillation, palpitations), chest pain, ischemia, myocardial infarction, syncope, and Henoch-Schonlein purpura syndrome have been reported during postmarketing experience.[Ref]


In the studies involving treatment of genital/perianal warts, the skin reactions reported were more frequent and more intense with daily application of the cream than with the application of the cream three times per week.

In studies involving treatment of actinic keratosis or superficial basal cell carcinoma, the dermatologic side effects classified as local and application site most frequently resulted in clinical intervention (e.g., rest periods, withdrawal from study, treatment site infections requiring treatment with antibiotics).[Ref]

Dermatologic side effects have included eczema (2%), alopecia (1%), dermatitis, and pruritus. Remote site skin reaction were reported and included erythema (3% in females, 1% in males), ulceration (2% in females), erosion (2% in males), edema (1% in females, 1% in males), induration (1% in males), and excoriation/flaking (1% in males). Remote site reactions reported in more than 1% of patients have included bleeding, burning, itching, pain, tenderness, and tinea cruris. Hyperkeratosis, rash, skin disorder, photosensitivity reaction, verruca, and remote site irritation have been reported. Imiquimod-induced psoriasis and at least 1 case each of vitiligo-like hyperpigmentation, contact pemphigus, pityriasis rubra pilaris exacerbation, erosive pustular dermatosis of the scalp, and eruptive keratoacanthoma have been reported. Exfoliative dermatitis, erythema multiforme, hyperpigmentation, hypopigmentation, and hypertrophic scar have been reported during postmarketing experience.[Ref]


Musculoskeletal side effects have included arthralgia (up to 3%) and myalgia (up to 1%). Arthritis and skeletal pain have been reported. Arthralgia has also been reported during postmarketing experience.[Ref]


Genitourinary side effects have included bacterial vaginitis (up to 3% of females), urinary tract infections (1%), scrotal pain, scrotal erythema, scrotal ulcer, and scrotal edema. Proteinuria, urinary retention, and dysuria have been reported during postmarketing experience.[Ref]


Psychiatric side effects have included anxiety (1%). Depression and suicide have been reported during postmarketing experience.[Ref]


Ocular side effects have included conjunctivitis and eye abnormality.[Ref]


Hypersensitivity side effects have included angioedema during postmarketing experience. Aggravation of allergy has been reported.[Ref]

A 61-year-old man developed angioedema 3 weeks into treatment for squamous cell carcinoma in situ located on the right forearm. One week prior he had developed ulceration over the application site. The angioedema started in the right hand at which time the imiquimod therapy was discontinued. Within 36 hours of discontinuation the angioedema had encompassed both hands and feet and the ulcerated application site. Fifty-four hours following discontinuation of therapy the patient was awakened by severe swelling of the tongue, diagnosed by the emergency room physician as angioedema of the tongue. The patient experienced difficulty talking and swallowing, but no respiratory distress. The patient denied presence of chills, fever, or influenza-like symptoms. The patient denied history of urticaria, angioedema, or anaphylaxis. The patient was stable on all medications prior to initiation of imiquimod therapy. The patient improved following treatment with intravenous diphenhydramine and methylprednisolone. It is thought that the large application site (16.7 m2) and the ulceration may have facilitated in the absorption of imiquimod resulting in the angioedema.[Ref]


Metabolic side effects have included hypercholesterolemia and gout.[Ref]


Hepatic side effects have included abnormal liver function during postmarketing experience.[Ref]


Endocrine side effects have included thyroiditis during postmarketing experience.[Ref]


1. "Product Information. Aldara (imiquimod topical)." 3M Pharmaceuticals, St. Paul, MN.

2. "Systemic reactions to imiquimod (Aldara)." Med Lett Drugs Ther 46 (2004): 92

3. Bayerl C, Feller G, Goerdt S "Experience in treating molluscum contagiosum in children with imiquimod 5% cream." Br J Dermatol 149 Suppl 66 (2003): 25-9

4. Bukhardt Perez MP, Ruiz-Villaverde R, Naranjo Diaz MJ, Blasco Melguizo J, Naranjo Sintes R "Basal cell carcinoma: treatment with imiquimod." Int J Dermatol 46 (2007): 539-42

5. Geisse J, Caro I, Lindholm J, Golitz L, Stampone P, Owens M "Imiquimod 5% cream for the treatment of superficial basal cell carcinoma: results from two phase III, randomized, vehicle-controlled studies." J Am Acad Dermatol 50 (2004): 722-33

6. Stinco G, Frattasio A, Forcione M, Quinkenstein E, Finato N, Patrone P "The appearance of inflammatory papules in the skin surrounding areas treated with imiquimod cream for basal cell carcinoma." Br J Dermatol (2007):

7. Tran H, Chen K, Shumack S "Summary of actinic keratosis studies with imiquimod 5% cream." Br J Dermatol 149 Suppl 66 (2003): 37-9

8. Vidal D, Matias-Guiu X, Alomar A "Efficacy of imiquimod for the expression of Bcl-2, Ki67, p53 and basal cell carcinoma apoptosis." Br J Dermatol 151 (2004): 656-62

9. Lebwohl M, Dinehart S, Whiting D, et al. "Imiquimod 5% cream for the treatment of actinic keratosis: results from two phase III, randomized, double-blind, parallel group, vehicle-controlled trials." J Am Acad Dermatol 50 (2004): 714-21

10. Yi BA, Nirenberg MJ, Goldstein SM, Berger TG "Chronic neuropathic pain associated with imiquimod: Report of 2 cases." J Am Acad Dermatol 52(2 Pt 2) (2005): 57-8

11. Yang FC, Jessup C, Dahiya M, Reynolds R "Pityriasis rubra pilaris exacerbation with topical use of imiquimod." Int J Dermatol 47 (2008): 1076-8

12. Campanelli A, Krischer J, Saurat JH "Topical application of imiquimod and associated fever in children." J Am Acad Dermatol 52 (2005): E1

13. Fernandez-Vozmediano J, Armario-Hita J "Infiltrative squamous cell carcinoma on the scalp after treatment with 5% imiquimod cream." J Am Acad Dermatol 52 (2005): 716-7

14. Fisher GH, Lang PG "Treatment of melanoma in situ on sun-damaged skin with topical 5% imiquimod cream complicated by the development of invasive disease." Arch Dermatol 139 (2003): 945-7

15. Barton JC "Angioedema associated with imiquimod." J Am Acad Dermatol 51 (2004): 477-8

16. Brown T, Zirvi M, Cotsarelis G, Gelfand JM "Vitiligo-like hypopigmentation associated with imiquimod treatment of genital warts." J Am Acad Dermatol 52 (2005): 715-6

17. Pini AM, Koch S, Scharer L, French LE, Lauchli S, Hofbauer GF "Eruptive keratoacanthoma following topical imiquimod for in situ squamous cell carcinoma of the skin in a renal transplant recipient." J Am Acad Dermatol 59(5 Suppl) (2008): S116-7

18. Lo Schiavo A, Sangiuliano S, Puca RV, Brunetti G, Ruocco E, Cozzi R "Contact pemphigus: a side-effect of imiquimod therapy." Int J Dermatol 47 (2008): 765-7

Some side effects of Aldara may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.