Pityriasis lichenoides (PL) is an uncommon skin rash of uncertain etiology. There are three different forms of pityriasis lichenoides, namely, pityriasis lichenoides chronica (PLC), pityriasis lichenoides et varioliformis acuta (PLEVA), and febrile ulceronecrotic Mucha-Habermann disease (FUMHD). Pityriasis lichenoides chronica (PLC) is rarely as symptomatic as it is alarming.
While the exact cause of pityriasis rosea is unclear, it may be linked to infections with certain strains of the herpes virus. That doesn't include the kind of herpes virus that causes cold sores. Pityriasis rosea is not contagious, so there's no need to avoid or limit contact with anyone when you have rashes.
Prevalence and Demographics
Although the disease occurs in people of all races and ages, there is a higher prevalence among males, and it tends to have a peak incidence in late childhood and into early adulthood. It is most common in children and young adults under age 30 but can present at any age. There is a slight male predominance.
What is Pityriasis Lichenoides Chronica (PLC)?
PLC is also known as chronic guttate parapsoriasis and parapsoriasis lichenoides chronica. PLC is not a lymphoma precursor. The major complication of the disease is cosmetic. With the lichenoid inflammation there is often post inflammatory hyperpigmentation in skin of color.
Characteristics of PLC Lesions
It is the chronic form of the disease characterized by evolving clusters of erythematous (red), scaly papules that usually persist for months. These lesions may relapse and remit over a period of years. At first, the lesions are small pink papules that turn red-brown. These evolve into a mica-like adherent scales attached to the center of the spots, which then flatten out over a period of many weeks to form brown spots that eventually fade away over time. Of the three forms of pityriasis lichenoides, PLC is the most common. The lesions have fine scale peels at their edges and may appear anywhere over the trunk, upper arms, and thighs and rarely affects the face or scalp. They are typically mild and do not form any scars when they heal. Individual lesions vary in size from 4-40 mm with an oval papulosquamous primary lesion. The long axes of the oval lesions tend to be parallel. One characteristic place to see a string-of -beads-like configuration of these lesions is around the axilla or inguinal region.
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Diagnosis and Differentiation
One key feature of PLC that aids in is differentiation from mycosis fungoides is the monomorphic nature of the lesions and their synchronous distribution in time (Figure 1). On the initial visit, the differential diagnosis is explained to the patient, along with the need for biopsy diagnosis. A punch biopsy is needed to see the bottom of the often wedged-shaped infiltrate. On the second visit the benign rhythmic nature of the condition is explained to the patient, along with the concept that therapy is dictated by symptoms. If the patient achieves clearing, it is worthwhile explaining that the intervals between outbreaks will be very important to monitor, as everyone has a different rhythm. A diary of some type would suffice.
The most surprising finding on biopsy is that if the pathologist is not aware of this being a monomorphous eruption of small papules, the pathology may be interpreted as being suspicious of mycosis fungoides. Typically there is a patchy lichenoid infiltrate that is very focal with overlying parakeratosis. Epidermotropic lymphocytes are not unusual. If the suspicion of mycosis fungoides is pursued the next surprising finding is that there often is T-cell clonality by molecular studies. If the clinical and pathologic features are not classic for PLC, immunochemistry may be useful in that CD8+ infiltrates are common and the lesions are clinically distinct from other CD8+ infiltrates, such as cytotoxic cutaneous T-cell lymphoma and varicella infection. No serology or imaging tests are indicated. The clinical and pathological correlation typically suffice for the diagnosis.
Conditions Mimicking PLC
However, there are two eruptions that can mimic PLC and to some degree overlap with it. One is the more virulent and scarring rhythmic eruption of lymphomatoid papulosis. The other is the pityriasis rosea-like drug eruptions.
Potential Causes and Associations
Although the cause of pityriasis lichenoides in general is unknown, it has been thought that PLC is caused by a hypersensitivity reaction to drugs such antihistamines and vaccines. As a fairly common condition, there have been numerous hints of this eruption being associated with the common viruses human herpes virus 6 and 7, Parvo virus, and Epstein-Barr Virus. There have been several cases reported of mycosis fungoides appearing in patients who exhibited PLC. In addition, it is not unheard of for patients with mycosis fungoides to exhibit PLC lesions in the background of their other cutaneous lesions.
The unusual clinical scenario one might encounter is a patient who has undergone a stem cell transplant for some type of hematologic malignancy. In that setting, the clinical and pathological features of PLC would be interpreted as a form of chronic graft-versus-host disease. This observation is useful in trying to answer the PLC patient’s question about “what causes this”? In the setting of a transplant, we know the cause.
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Pityriasis Lichenoides Et Varioliformis Acuta (PLEVA)
PLEVA is a more severe and less common version of PLC. It is also known as acute guttate parapsoriasis and parapsoriasis lichenoides et varioliformis acuta. Patients often show features of both PLEVA and PLC, and PLEVA may evolve into PLC.
Characteristics of PLEVA Lesions
The lesions of PLEVA are characterized by red patches that quickly evolve into papules. These lesions may occur singly or may present in groups with the possibility of coalescing to form very large areas of rash. While PLC does not cause itching, PLEVA manifests with a burning and itching sensation and may cause scarring and skin discoloration. Despite their dissimilarity in intensity, PLEVA has a similar distribution on the body like PLC and is also proposed to have infectious triggers such as EBV, PVB19, HIV, and toxoplasmosis. Pityriasis lichenoides et varioliformis acuta typically resolves within a few weeks. However, this can be variable and PLEVA may evolve into PLC or a scar.
Febrile Ulceronecrotic Mucha-Habermann Disease (FUHMD)
FUHMD is the most rare and aggressive of the three forms of pityriasis lichenoides with a reported mortality rate of 20% in adults.
Characteristics of FUHMD Lesions
FUHMD typically begins as PLEVA, but then very rapidly deteriorates to a condition with large ulcers that are filled with pus and blood that are often responsible for secondary infections. There is usually an accompanying high fever with painful skin tissue loss, and many signs including sore throat, abdominal pain, splenomegaly (enlarged spleen), conjunctival ulcers, and other nonspecific symptoms. Rapid diagnosis and treatment of FUHMD is essential to reduce morbidity and death associated with the disease. Due to increased serum levels of tumor necrosis factor alpha (TNF-a), TNF-a inhibitors have been employed as first line treatment in the fight against FUHMD.
Management and Treatment Options for PLC
Given the lack of symptoms, many patients tend to ignore it and given the disease’s natural history of spontaneous involution their wishes tend to be fulfilled-it goes away. Thus, a history of a rhythmic eruption that fades is a key finding in the history. The safest therapy touted for PLC is also the least reliable, but worth pursuing due to the benign nature of the drugs: antibiotics at acne doses and durations. The major factor complicating any efficacy assessment is the remitting nature of the disease. If the patient clears after a month it would be prudent to claim victory and wait for the next outbreak before any more antibiotic is dispensed. If there is no response, 1 to 2 months is adequate time to determine treatment failure.
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Topical and Systemic Treatments
This is probably the most commonly used approach, since many patients do this at home before and after seeing a dermatologist. In order of ease of administration and patient acceptability it is not unusual to utilize phototherapy to clear up old lesions and inhibit the development of new ones for a given period of time. Obviously a patient could not continue multiple photoptherapy sessions per week for life, but long remissions can be achieved from a 2-3 month course of treatment. Tanning parlors are often the modality of choice for patient convenience and expense. The macrolides erythromycin, azithromycin, and clarithromycin at doses of 250mg to 500mg per day for at least 2 months have been the most popular. The most reliable systemic therapy for PLC is weekly methotrexate at doses similar to those successful for psoriasis. One unique feature of PLC is that once controlled with methotrexate the dose can often be reduced to 5mg per week to suppress new crops from appearing. Almost all patients undergo a course of antibiotics, given the ease of administration and lack of need for laboratory monitoring of this treatment. Azithromycin 250mg per day is a well-tolerated dose.
Home Management and Lifestyle Adjustments
As a published author, I thought my third book might center around living with PLC (or pityriasis lichenoides chronica) - a diagnosis I received in my teens and have lived with ever since. The chronica implies that I will have spotted skin (seasonally reddish or white) as long as I am alive. Earlier this year, I experienced nothing short of a miracle. After going through most of my life not personally knowing a single other soul that shared my PLC diagnosis, one showed up in the most unlikely of ways. I shared my diagnosis via social media. As a writer, I believe in honesty and transparency with my audience, but I had never directly shared my skin condition. A dear friend responded with, “You have PLC?! So does Anissa (her daughter)!” I sat there looking at the response, stunned. Anissa, now a high school senior that I’ve known since she was a little girl, was soon to be my piano student. Since then, we have bonded over many PLC stories and exchanged advice. She is about 20 years younger than me and deals with the condition with much more grace and wisdom than I did at her age. In managing pityriasis lichenoides chronica:
- Take helpful supplements. I personally take Bromelain, a natural supplement that comes from pineapple, daily (I buy in bulk on Amazon). While I still have white, discolored patches of skin during this fall season, it seems to help keep the red bumps at bay, or at least, manageable.
- The sun, sand and saltwater are your friends. If you don’t have easy access to a beach, try bathing with Epsom salt, which is also effective. My favorite thing to do is exfoliate my skin with sand, rinse off in the ocean and get a safe amount of sun while lathered in sunblock.
- Find an eating schedule that works for you. I’ve personally been trying intermittent fasting. This popular trend that I started just eight weeks ago seems to have positively affected my largest organ, too! Since I’m asleep for most of the other hours, it’s been super manageable.
- Prescribed topical ointment. My favorite brand is Triamcinolone Acetonide Cream, 0.1%. I resort to this prescribed, topical ointment only when I have a bad breakout (this usually happens in winter, between December and February). Your dermatologist can prescribe this if you don’t already own it. Fair warning: excessive use over the years can lead to your skin thinning.
- Celery juice. Chances are you’ve heard of the effects of celery juice. Next to modifying my diet, drinking 16 oz of this juice every morning (that I typically cut with an apple) was the most successful in giving me mostly clear skin.
Pityriasis Rosea
Pityriasis rosea, a rash that usually appears on the torso, upper arms, thighs, or neck, may sound worse than it really is. The condition has a name that’s hard to say: pit-ih-RIE-uh-sis ROW-zee-ah. But it’s common and fairly easy to treat.
Symptoms of Pityriasis Rosea
The symptoms of pityriasis rosea usually develop in stages:
- You may initially develop a fever, headache or upper respiratory infection.
- You may develop a raised, discolored, circular or oval-shaped patch that ranges from 1 to 6 centimeters (cm). This patch is the “herald” or “mother” patch.
- About one to two weeks later, discolored circular or oval-shaped patches appear in groups near the herald patch. These patches are smaller than the herald patch - they range from 1 to 2 cm - and are often called “daughter” patches. They develop in a pattern that resembles sagging Christmas tree branches.
- In approximately 50% of people with pityriasis rosea, the patches itch.
- In darker-skinned or Black people, the patches may be more raised (papular), and the centers of the patches may look like the tissue is dying (necrotic).
Pityriasis rosea doesn’t hurt. However, if you scratch your patches, you may break your skin, leading to an infection that can cause pain.
Causes and Risk Factors for Pityriasis Rosea
Healthcare experts believe herpesvirus 6 (HHV-6), HHV-7 and/or HHV-8 cause pityriasis rosea, but there aren’t any conclusive studies. These strains of the herpes virus aren’t related to the strains that cause cold sores or genital herpes. Studies show that some skin conditions may appear with COVID-19, including pityriasis rosea. However, the studies don’t conclusively prove that COVID-19 causes pityriasis rosea.
Though pityriasis rosea can affect anyone, you may be more likely to get it if you’re:
- Between the ages of 10 and 35.
- A woman, as women are 50% more likely to get pityriasis rosea.
- Pregnant.
- Dealing with serious or long-term stress. Though some people have gone through this, there isn’t enough research to confirm this triggers pityriasis rosea.
Diagnosis and Treatment of Pityriasis Rosea
A dermatologist, a doctor who treats skin conditions, can usually diagnose pityriasis rosea by sight. To make sure, they may order a blood test, scraping, or biopsy. Those tests can rule out other types of skin problems, including eczema, ringworm, and psoriasis.
While the rash itself doesn't need treatment and will go away on its own, usually within 6-8 weeks, you can go to your dermatologist for treatment or pityriasis rosea medication to soothe symptoms. They may suggest:
- Antihistamines. These allergy medicines can help ease itching and can come in the form of a cream or pill.
- Corticosteroids. This kind of cream is made to treat skin dryness, scaling, and itching. One type your doctor may suggest is triamcinolone ointment.
- Over-the-counter topical medications. Calamine lotion or zinc oxide may help you feel less itchy.
- Prednisone. This is a steroid medicine taken by mouth and can help with serious itching.
- Acyclovir. A type of antivirus medicine, acyclovir (Valtrex, Zovirax) may help the rash go away sooner in some people.
- UVB phototherapy. Also known as light treatments, this treatment exposes your skin to natural or artificial light to lessen symptoms. Keep in mind that light therapy can leave lasting dark spots on your skin, even after the rash clears.
You should talk to your doctor before using any medication.
Home Remedies for Pityriasis Rosea
Along with prescribed treatments, there are some home remedies for pityriasis rosea self-care that can help stop itching and soothe and protect your skin.
- Creams
- Anti-itch lotion, such as hydrocortisone cream
- Calamine lotion for itch relief and moisturization
- Protect your skin from the sun by generously applying a broad-spectrum sunscreen with at least 30 SPF, even on cloudy days. Reapply every 2 hours or more often if swimming or sweating.
- Natural ingredients
- One of the most popular home remedies for pityriasis rosea is oatmeal because it can help soothe itching. It is finely ground to a powder and then mixed with warm water to form a paste. Apply the paste to rashes for 10 minutes, then wipe it off. You can also bathe or shower in lukewarm water and use an oatmeal-based bath product.
- Other natural treatments you can use on your skin include:
- Aloe vera
- Coconut oil
- Neem leaf (boiled and put in a bath)
- Lavender oil
- Safflower oil
- Tea tree oil
Anti-Inflammatory Diet
While you don't have to avoid any food or drinks if you have pityriasis rosea, some people believe eating anti-inflammatory food can help lessen itching.
These types of food include:
- Oily fish, such as mackerel, salmon, or sardines
- Leafy greens, such as spinach and kale
- Olive oil
- Tomatoes
This diet also avoids food that can worsen inflammation, such as:
- Fried foods, including many fast-food items.
- Cured meats with nitrates, such as hot dogs.
- Highly refined oils and trans fats.
- Refined carbohydrates, such as sugar, pastries, and white bread.
Distinguishing Pityriasis Rosea from Ringworm
Pityriasis rosea and ringworm look similar. They’re both papulosquamous (pap-you-lo-skway-miss) disorders, which is a term used to characterize skin disorders according to the presence of raised, discolored, scaly patches of skin.
However, a fungus causes ringworm. No one knows what causes pityriasis rosea, though healthcare experts think a virus might be responsible.
Pityriasis Rosea and Pregnancy
If you develop symptoms of pityriasis rosea while pregnant, contact your healthcare provider right away. Pregnant women are one of the groups that have a higher chance of getting serious complications from this condition. If you’re pregnant and get pityriasis rosea, see your OB/GYN at once. In one small study, a majority of women who got the rash in the first 15 weeks of pregnancy had miscarriages.
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