Aminolevulinic Acid (Topical)

Aminolevulinic acid is part of a class of medications called photosensitizing agents, which treatments that are activated by photodynamic therapy (called PDT or special blue light) to cause their desired effect. The solution is applied topically over areas of the skin affected by these lesions, and then a light is cast on the areas, destroying the keratoses.


Aminolevulinic acid is a topical solution used in conjunction with light to destroy skin lesions called keratoses. These are crusty, scaly blemishes that often take bump or horn shapes, and most commonly appear on the face or scalp. If left untreated, they can become cancerous. Usually, they are harmless but unsightly, and most people who have them desire to remove the lesions as soon as possible. Aminolevulinic acid is applied to these lesions using a specially designed applicator, and within 14 - 18 hours is activated by the application of special blue light, which causes the acid to damage the keratoses cells, destroying the lesions.

The therapy is usually effective, and patients typically do not need further treatment in the same areas. Eight weeks after the treatment, caregivers will examine patients treated with the aminolevulinic acid and light combination for any signs of the keratoses or development of new ones. If any are found, the treatment may be repeated if deemed necessary by the caregiver.

Conditions treated

  • Skin lesions (particularly keratoses)

Type of medicine

  • Photosensitizing agent

Side effects

Major side effects are not common. However, the possibility for serious reactions is present. If an allergic reaction (closing of throat, shortness of breath, swelling of lips,face, tongue, or hives) occurs, emergency medical attention must be sought immediately. Call 911 or the poison control center at 1-800-222-1222 if an allergic reaction occurs.

Common side effects include tingling, stinging, pricking or burning of lesions, during the blue light treatment, though these should improve within 24 hours. Redness, swelling, and scaling of the treated actinic keratoses and surrounding skin can also be felt, but these should improve within four weeks.

Further side effects are:

  • Discoloration of the skin
  • Itching
  • Bleeding
  • Blistering
  • Pus under the skin
  • Hives

Additionally, the lesions will change significantly in appearance after treatment, with most becoming erythematous. Some have also been known to become edematous. Both the edema and erythema should resolve to baseline or show improvement at least four weeks after the therapy. At this time skin should show little to no sign of the keratoses.


Aminolevulinic acid is typically distributed in a plastic tube containing two glass ampules and an applicator tip. One ampule contains 354 mg of the dry aminolevulinic acid HCI solid, while the other contains 1.5 ml a solution comprised of alcohol USP, water, isopropyl alcohol and polyethylene glycol. Just prior to application, the ampules' contents are mixed together by shaking them in the applicator. The applicator tip is then dabbed on a gauze pad until it becomes wet with the solution.

The lesions should be cleaned and dried before application. The solution is then applied to the lesions directly, using a dabbing motion. Application should be uniform over the entire lesion, and ensure coverage of the edges. The solution should not contact ocular or mucosal surfaces. Application should occur twice. Once the first application has dried, the caregiver will perform a new application using the same method as the first one.

For the next 40 hours after the application of aminolevulinic acid, the patient should wear protective apparel (such as hats) to shade the affected areas of the skin from excessive light. Exposure to sunlight and other strong illumination should be kept to a minimum during this period, especially before the light therapy.

Before the patient receives the light therapy, the lesions should be rinsed with water and patted dry. The illumination used for activation of the lesions is known as Blu-U illumination, from a Blu-U Blue Light Photodynamic Therapy illuminator. The patient receives 16 minutes and 40 seconds of this light, producing a 10J/cm^2 dose.

Patients and caregivers should wear protective eyewear during the process. If treatment is interrupted or stopped for any reason, it is not restarted, and patient is cautioned to provide protection for the affected lesions for the remainder of the 40 hour period that began after treatment with the topical solution.

There are specific guidelines for positioning the illuminator, depending on the location of the patient's lesions.

For facial lesions, the Blu-U Blue Light Photodynamic Therapy Illuminator is positioned so that the base is slightly above the patient's shoulder, parallel to the patient's face. The Blu-U is then positioned around the patient's head, so that the entire treatment area lies within a two to four inch distance from the Blu-U surface. The patient's forehead and cheeks should be no further than four inches from the surface, and the sides of the patient's face and ears should be no closer than two inches from the surface.

Patients with scalp lesions require the Blu-U to be rotated to a horizontal position. The Blu-U should be positioned around the head in a way where the treatment area lies between two and four inches from the Blu-U surface. The scalp should be no closer than two inches from the surface and four inches from the surface. The sides of the patient's face and their ears should be no closer than two inches to the Blu-U surface.

A chin rest should be used to provide patient comfort during the process.

If the patient cannot arrive for light therapy in the required timeframe, it is important to reschedule the appointment for the light portion as soon as possible. The lesions may become sensitive or painful if the light is not applied in time. The light is essential for the topical solution to work.

Drug interactions

Interactions between aminolevulinic acid and other drugs have not been formally studied. Clinical trials yielded no evidence of significant interactions between aminolevulinic acid and other medications.

One potential issue is the combination of aminolevulinic acid with other photosensitizing medications. Among these are griseofulvin, thiazide diuretics, sulfonamides, and tetracyclines. Medcations such as these may increase photosensitive reactions of actinic keratoses when aminolevulunic acid is used in their treatment.

It is recommended to inform your caregiver if you are currently taking, or cease taking while being treated with aminolevulinic acid, the following medications:

  • an antibiotic or sulfa drug
  • a diruetic or 'water pill'
  • medicine to treat nausea or vomiting
  • antipsychotic medication
  • an oral diabetes medicine

These drugs have components that are known to interact with the aminolevulinic drugs. The caregiver may take precautions, such as modification of dose or the use of an alternative treatment. It is important to minimize risk while giving medications.


Before beginning aminolevulinic acid treatment, tell your healthcare provider if you have had lupus, blood clotting or bleeding disorders, such as hemophilia, or poryphyria (a genetic enzyme disorder that affects the nervous system or skin). Presence of conditions such as these may cause your care provider to modify treatment or devise another treatment strategy.

Aminolevulinic acid contains alcohol and may only be used topically. Application to the eyes or mucous membranes should never be done. Applying the product under occlusion may cause excessive irritation.

After treatment is complete, the treatment areas will become photosensitive. The areas should be shielded from bright indoor lights, such as tanning beds, operating room lamps, examination lamps, or any light at close proximity. Sunlight should also be avoided. Stinging or burning sensations, as well as edema and erythema, can be caused when lesions are exposed to excessive light. If patients must go out into sunlight, head coverings of light opaque material must be worn. Photosensitive reactions are not prevented by sunscreen. The effects of perspiration on treatment areas is not known.

Aminolevulinic acid, if applied to perilesional areas of photodamaged skin, may result in photosensitization. The patient may feel a painful or stinging sensation upon light exposure if these areas are exposed to aminolevulinic acid. Only healthcare professionals should apply the aminolevulinic acid in order to ensure that the solution only contacts the active keratoses and not perilesional skin. Testing of the solution on patients with inherited or acquired coagulation defects has not been performed.

Carcinogenesis, mutagenesis, and impairment to fertility

Carcinogenecity testing has not been performed using aminolevulinic acid. Potential evaluation studies conducted with aminolevulinic acid found no evidence of mutagenic effects.

Aminolevulinic acid is not known to have any effect on fertility or reproductive function, and neither are the effects of aminolevulinic acid on pregnancy known. However, extreme caution should be taken when pregnant women use aminolevulunic acid. Women should not breastfeed for 12 hours after taking aminolevulinic acid. The consensus is that pregnant women should only take aminolevulinic acid if it is deemed absolutely necessary by their caregiver.


Overdoses of aminolevulinic acid have not been reported. The drug is administered exclusively in professional medical settings, so an overdose is not likely to occur. Ingestion of the solution is highly unlikely, but should be responded to with supportive care and monitoring. The affected person should also avoid light exposure for 40 hours after ingestion. Excessive exposure to the Blu-U light has also not been reported.

Contraindications have been reported when patients with cutaneous photosensitivity at the 400-450 mm wavelengths, porphyria or known porphyrin allergies are treated with aminolevulinic acid.


Aminolevulinic acid topical must be used within two hours of preparation. If the solution exceeds this time period it should be discarded. Unprepared tubes are stored exclusively in professional medical settings. The drug is not for home use, and should only be administered by trained professionals.


Aminolevulinic acid is an effective topical treatment for keratosis. In conjunction with light therapy, it is effective in permanently curtailing growth of kerotoses. The treatment consists of a part ACA, part alcohol-based topical solution. Two doses of the topical solution are applied by a medical professional.

For 40 hours after the application, the areas must be shielded from strong lights such as operating lamps and sunlight. 14 - 18 hours after the topical medication is applied, a specialized light therapy device is utilized to activate the solution. The chemical reaction destroys the cells that comprise the lesions, which are consequently be eliminated.

While some minor uncomfortable side effects are present, they are not usually serious and quickly subside. However, some reactions warrant medical attention, and must be monitored. Care must be taken throughout the treatment process.

Last Reviewed:
December 10, 2017
Last Updated:
April 04, 2018