What is Lichen Striatus?
Lichen striatus (LS) is a less common condition that usually appears in children. It manifests as a pink rash with elevated spots that merge to create single or multiple, flat-red, and possibly flaky lines, following the pattern of the Blaschko lines. The Blaschko lines are ordinarily unseen, but conditions like lichen striatus can make them visible.
What Causes Lichen Striatus?
The exact cause of lichen striatus, a skin condition, remains uncertain. However, it’s believed that factors such as genetics and environmental triggers could be involved. One theory suggests that people who have a genetic likelihood to allergic reactions (a condition known as atopy) could be more susceptible to lichen striatus. This theory is backed by a research where around 85% of lichen striatus patients were found to have a family history of allergic conditions, such as skin inflammation due to allergies (atopic dermatitis), asthma, or allergies affecting the nose (allergic rhinitis).
But it’s worth mentioning that not all studies support this view. Others findings point towards the body’s immune reaction to pregnancy as a possible cause. Another link could also be to vitiligo, a different skin condition where certain skin areas lose their colour. Some reports suggest that lichen striatus might happen as a side effect of using certain drugs like adalimumab and etanercept. Other observations propose that lichen striatus arises due to an inflammatory response caused by a type of white blood cells, T-cells.
In addition to genetic factors, environmental triggers are also thought to contribute to lichen striatus. For instance, there have been cases where unrelated children living in the same surroundings experienced the condition together. A possible connection to viral infections has also been suggested, based on an increased level of a protein called interleukin 1-beta found in these patients’ skin samples. But the evidence acknowledging this connection is not entirely conclusive. Lichen striatus’ occurrences have also been reported after receiving BCG and hepatitis B vaccines, exposure to sunbed UV rays, contact with a pineapple leaf, a bumblebee bite, or after chickenpox and flu infection.
Another theory suggests that lichen striatus might be a result of ‘epigenetic mosaicism,’ a phenomenon where different cell groups exist within one individual exhibiting different genetic codes. This study argues that a person with lichen striatus could be genetically predisposed to this condition. An infection could trigger an immune response, leading to specific changes in the genetic elements within cells. Finally, there have also been reports linking lichen striatus to viral infections of herpesvirus 6 and 7.
Risk Factors and Frequency for Lichen Striatus
Lichen striatus, also known as acquired blaschkoid dermatitis, is a condition mostly diagnosed in children between the ages of 5 and 15, and it’s rarely seen in adults. This condition doesn’t favor any particular race.
- Over 50% of diagnosed cases are in children between 5 and 15 years old.
- Very rarely does it occur in adults.
- It’s also known as acquired blaschkoid dermatitis.
- No specific race is more likely to get lichen striatus.
- Some studies show it’s 2-3 times more common in girls than boys.
- However, many other studies show an equal distribution between both sexes.
- There is no agreed-upon understanding as to which sex is more likely to have it.
Signs and Symptoms of Lichen Striatus
Lichen striatus is a skin condition that appears as a spontaneous eruption of a pink rash. It starts with small raised spots, also known as papules, that merge to form a single or multiple, dull-red, sometimes scaly, linear stripe following a specific pattern on skin known as Blaschko lines. Unlike other skin lines, these lines don’t come from the nervous or circulatory system. The pattern often appears on the arms and legs, but can also show up on the buttocks, neck, and torso. While the condition generally doesn’t cause any discomfort, some individuals may experience itching. The good news is, these skin lines often clear up on their own. However, in a few cases, they may leave behind darker (hyperpigmentation) or lighter (hypopigmentation) spots on the skin.
Testing for Lichen Striatus
Lichen striatus is a skin condition that can be identified by its unique visual characteristics and by examining a sample of the skin under a microscope, a procedure known as a skin biopsy.
Treatment Options for Lichen Striatus
This condition usually gets better on its own, and treatment isn’t always necessary. However, if you’re uncomfortable and want treatment, there are several options available.
Emollients are lotions or creams that can moisturize your skin and relieve any dryness or itchiness. If these don’t work, low-dose systemic corticosteroids, a type of medication that helps to reduce inflammation, may be used.
A short course of acitretin, which is a medicine often used to treat severe skin conditions, and topical steroids, which are creams or lotions applied directly to the skin to reduce inflammation and itching, could also be used.
If these treatments don’t provide relief, photodynamic treatment is another option. This therapy uses a special light-activated drug, aminolevulinic methyl acid, to treat the skin – much like a very targeted sunbed.
For persistent and itchy skin lesions, especially those on the face and arms and legs, tacrolimus and pimecrolimus creams can be used.
Lastly, if you notice any abnormalities with your nails, these can also be treated with tacrolimus.
What else can Lichen Striatus be?
When analyzing symptoms, doctors need to be cautious in distinguishing Lichen striatus from other similar conditions such as Lichen planus or Lichen planus-like keratosis. In these other conditions, kertainocytes, a type of skin cell, die off primarily only in the bottom layer of skin as opposed to all layers as found in Lichen striatus. Also, normally, these conditions don’t typically impact your sweat glands.
Doctors also need to ensure they rule out the following conditions that may seem similar:
- Nevus unius lateris
- Annular lichenoid dermatitis
- Unilateral laterothoracic exanthema
- Tinea corporis
- Inflammatory linear verrucous epidermal nevus
- Linear Darier disease
- Lichen Nitidus
- Lichen Planus
- Lichen Simplex Chronicus
- Nongenital Warts
- Plaque Psoriasis
- Porokeratosis
What to expect with Lichen Striatus
LS, due to its self-healing nature, has a great prognosis, meaning the long-term view of the condition is generally good and complete recovery is expected. This condition often entirely disappears on its own within a year, but this can range from as short as four weeks up to three years. It’s not common for the condition to come back once it’s gone.
The part of this condition that affects your nails also typically corrects itself over time, possibly taking anywhere from six months to five years. Importantly, when it goes away, it does so without leaving any lasting changes or deformities in the nails.
Possible Complications When Diagnosed with Lichen Striatus
Complications from this condition are not common and don’t happen very often. Some people might experience changes in skin color that continue for several months or even years after the skin condition gets better. These changes can include areas of skin becoming darker (hyperpigmentation) or lighter (hypopigmentation).
Effects of the Condition:
- Darker skin areas (postinflammatory hyperpigmentation)
- Lighter skin areas (hypopigmentation)