Also called: Henna Allergy
Henna stain allergy is a reaction to ingredients often used in temporary tattoos created through a process known as mehndi. Traditionally associated with rituals in Indian, North African, Mediterranean and Asian cultures, this form of body-painting has recently become trendy in Western countries.
Henna is a plant-based coloring that rarely causes allergic reactions. However, additives sometimes used to enhance henna coloring or speed up the tattooing process have caused intense bouts of contact dermatitis in some people. There have also been reports of patients who immediately react to the henna paste after it is applied, displaying symptoms such as swelling, sneezing and difficulty breathing. The U.S. Food and Drug Administration (FDA) has singled out the “coal tar” dye p-phenylenediamine, also known as PPD, as a source of many of the problems associated with henna stain allergy.
The FDA has not approved henna for use in direct skin applications. Those who become sensitized to henna, PPD or other ingredients will remain at risk of reacting to those substances for the rest of their lives. Therefore, it is crucial to be aware of exactly which ingredients are being used to create the henna paste used by a mehndi artist or henna tattoo practitioner.
About henna stain allergy
Henna stain allergy is a growing concern due to the recent popularity of temporary tattoos. This form of body painting has a long tradition in India, Fiji and Morocco. It is known as mehndi, and traditionally has been used as a decorative painting on the hands and feet for social rituals.
In mehndi, tattoos are applied using coloring called henna, which is made from the leaves of an Asiatic and North African shrub called Lawsonia inermis (also known as the Egyptian privet or the Jamaica mignonette). The leaves are ground into powder and mixed with oil, lemon and other ingredients to form a paste.
Unlike permanent tattoos, ink is not injected under the skin in mehndi. Instead, the pattern is applied to the skin surface using a moistened wad of cotton, fine brushes or a plastic-bottle applicator. The paste is left on the skin for two to 12 hours while the pigment binds to the skin. The tattoo usually remains visible until the outer layer of skin exfoliates. Depending on the thickness of the skin, this takes anywhere from a week to six weeks or more.
Henna produces a brown, orange-brown or reddish-brown tint, but ingredients such as coffee and beet juice sometimes are added to henna to produce darker colors. Essential oils, such as eucalyptus and clove, may also be added to scent the henna. The additive p-phenylenediamine (PPD) is used to produce “blue henna” or “black henna.”
Some ingredients added to henna may trigger allergic reactions. This is particularly true of PPD. Most people with henna allergies develop contact dermatitis a few days after henna has been applied to their skin. There have also been reports of patients who immediately react to the henna paste after it is applied, displaying symptoms such as urticaria, sneezing and asthmatic reactions.
The U.S. Food and Drug Administration (FDA) has approved henna for use in hair dyes, but not for direct application to skin.
Potential causes of henna stain allergy
Despite the widespread use of henna, reports of contact dermatitis (skin inflammation caused by contact with an allergen or irritant) and other allergic manifestations associated with the coloring have been rare. Henna itself is considered a weak sensitizer. However, people sometimes have allergic reactions to additives that are used to enhance the coloring of henna.
For example, the U.S. Food and Drug Administration (FDA) has warned that “black henna” may contain the “coal tar” color p-phenylenediamine, also known as PPD. This ingredient has been approved for use only as a hair dye, and may cause an allergic reaction when applied to skin. It is used to blacken the coloring of henna, which is naturally reddish-brown. People who become sensitized to PPD will remain that way for life. This means they will have to exercise caution to avoid exposure to PPD found in some dark-colored cosmetics, black rubber, photocopying and printing inks, ballpoint pen inks, oils, greases and gasoline. Other potential sources of PPD contamination include textile and fur dyes, and photographic developer and lithography plates.
People with sensitivity to PPD must also be careful not to use hair dyes or nail polish that contain the ingredient, and should ask a physician about whether to avoid dark–colored clothing (blue, black or brown) that may contain PPD.
PPD sensitivity may also prohibit the use of substances or medications. These include:
- Sunscreens and creams that contain para-aminobenzoic acid (PABA)
- Sulfa medications including some antibiotics
- Epoxy hardeners
- Topical anesthetics such as benzocaine and procaine
The FDA also has warned about the use of other ingredients, such as solvents, used in some henna-based dyes. These are sometimes added to speed up the tattooing process.
Signs and symptoms of henna stain allergy
A contact dermatitis reaction is the most common symptom of henna stain allergy. Red, itchy blisters may begin to appear around the tattoo within two to 10 days of application. It is often the additive p-phenylenediamine (PPD) in the henna dye that causes the reaction. In some cases, this dye has caused a permanent loss of skin color in the shape of the tattoo. This process is known as hypopigmentation.
There have also been reports of patients who immediately react to the henna paste after it is applied, displaying symptoms such as urticaria, sneezing and asthmatic reactions.
Diagnosis and treatment of henna stain allergy
A physician will conduct a physical examination of the patient and examine the appearance of the skin. The physician will also compile a medical history and a list of symptoms. If an allergy is suspected, the physician will perform one or more allergy tests (e.g., allergy skin test).
Contact dermatitis is the most common symptom of henna stain allergy. There are several types of effective self-care treatment measures recommended for the treatment of contact dermatitis. These include:
- Applying calamine lotion and cool oatmeal baths to relieve itching
- Applying cold compresses to the blisters directly
- Applying hydrocortisone creams (nonprescription strength) to the skin
- Applying antihistamines directly to the skin to relieve itching
- Applying moisturizers to help restore the normal texture of the skin
- Washing with cool, soapy water immediately after exposure to neutralize and remove the offending substance
Prescription antihistamines may be used if over-the-counter antihistamines do not relieve the itching. Prescription corticosteroid medications may be topically prescribed to treat inflammation in a confined area.
Topical corticosteroid medications may lessen the inflammation but should be used carefully, as topical steroids can cause their own skin condition. If the rash covers a large portion of the skin or is severe, a physician may prescribe corticosteroid pills or injections. These are usually tapered gradually over a two-week period to prevent the recurrence of the rash. The healing period for a reaction to the additive p-phenylenediamine (PPD) may be extensive and take several weeks.
Prevention methods for henna stain allergy
People who have even a single episode of a contact dermatitis or another allergic reaction to henna or another additive associated with mehndi are at greater risk for experiencing a severe allergic reaction with future exposures. For this reason, healthcare professionals urge those with a previous reaction to henna to avoid future mehndi tattoos. In addition, hair dyes that contain henna should be avoided.
Many people who react to a henna tattoo are allergic to p-phenylenediamine, also known as PPD. This dye, which is added to henna to darken the color, is a potent sensitizer. Those with henna stain allergy must avoid any product that contains PPD. For a listing of products, see Potential causes.
The Fair Labeling and Packaging Act requires that all cosmetics sold on a retail basis in the United States list ingredients on the label. However, this law does not apply to cosmetic samples or products used exclusively by professionals. For this reason, customers must be careful when shopping for or applying cosmetics at a salon or booth at a fair. It can be very difficult to know exactly what is in these products.
Federal law also requires U.S. Food and Drug Administration (FDA) approval of all color additives used in cosmetics (except coal tar used in hair dyes). However, the FDA does not have the authority to approve or reject cosmetic products or ingredients, only to regulate drugs. Cosmetic products that have not been proved safe must carry the following label:
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding henna stain allergy:
- Do my symptoms indicate a henna stain allergy?
- What tests will you use to determine if I am allergic to henna stain?
- Does having a henna stain allergy pose a danger to my overall health?
- What are my treatment options?
- When can I expect my symptoms to subside?
- Are certain colors of henna stain more likely to cause me to have a reaction?
- Should I avoid mehndi tattoos from now on?
- Are there other products I should avoid?