Pityriasis Lichenoides

 

Introduction

Pityriasis Lichenoides can occur in two forms: acute and chronic, but there is an overlap between them. The acute form is called: PLEVA which is Pityriasis Lichenoides et Varioliformis Acuta also known as Mucha-Habermann's disease. The chronic form is called Pityriasis Lichenoides Chronica. They are mild forms of lymphocytic vasculitis. There is an occasional overlap with lymphoma if the biopsy report reveals the diagnosis of lymphomatoid papulosis, but this is not common.

 

 

Pityriasis Lichenoides et Varioliformis Acuta

Is possibly mediated by an immune system process which forms something called immune complexes. The  immune complexes attach to the dermal capillaries of the skin and cause an inflammatory process. With immune complex deposits, you get the characteristic hemorrhagic papules of  PLEVA.

 

The exact cause of PLEVA is unknown.

 

PLEVA can occur at any age but it's more common in young people. The lesions can be limited or widespread. They consist of vesicles and pustules which become hemorrhagic and necrotic and may leave a pitted chicken pox like scar with loss of pigment. Because they resemble chicken pox, they are hence called Varioliformis. It appears as a rash which can last from several weeks to several months, and the patient may have several episodes over a number of years. Look for discrete pea sized crusty raised pink to red palpable lesions. The lesions are scattered rather than grouped, and are more painful than itchy. They develop in crops over a period of time. Occasionally, small blisters evolve with a hemorrhagic and eroded center. Patients sometimes have malaise and low grade fever before the eruption. Lesions may occur anywhere except for the mouth.

 

A skin biopsy may help reveal the diagnosis. A biopsy will show lymphocytic vasculitis with small lymphocytes invading the dermal capillaries.

 

For PLEVA, Dr. Jacobs usually begins therapy with tetracycline, erythromycin, or Dynabac antibiotics. Prednisone or methotrexate are sometimes helpful. Severe resistant cases may be helped by ultraviolet light therapy at the local university (Loma Linda).

 

Pityriasis Lichenoides Chronica

PLC is a chronic scaling eruption of the limbs. Because it is rare, the eruption is very difficult to diagnose, and the patient may go from doctor to doctor looking for the diagnosis.

 

PLC is an uncommon condition that affects children and young adults. There may be mild fever and malaise prior to the outbreak of the condition. A doctor may see several cases during one period of time, and then see none for quite a while. It is thought that a virus may initiate the formation of immune complexes as in PLEVA.

 

The chronic scaling eruption of PLC is found on the legs and upper extremities, especially on the inner aspects. The initial lesion is a purple macule that rapidly becomes a reddish brown papule. As the lesion flattens, it develops an adherent scale and becomes somewhat pink. Darkening of the skin called postinflamatory hyperpigmentation may occur. PLC is chronic, though it may go into remission after a number of years.

 

A skin biopsy may help reveal the diagnosis. A biopsy will show a lymphocytic infiltrate which surrounds and sometimes involves small blood vessels, causing vascular damage.

 

For PLC, Dr. Jacobs usually begins therapy with tetracycline, erythromycin, or Z Pack antibiotics. Prednisone or methotrexate are sometimes helpful. Severe resistant cases may be helped by ultraviolet light therapy at the local university (Loma Linda).

 

What causes PLEVA and PLC?

The exact causes of PLEVA and PLC are not known. They are definitely not caused by a fungus or bacterial infection, and they are not caused by anything that a person has eaten. They are also not due to any known type of allergic reaction.  A virus is the most likely cause.

 

Who usually diagnoses it?

The diagnosis of PLEVA or PLC is usually made by the dermatologist, a physician with special training in skin diseases. The appearance of the rash may not be typical, however, making the diagnosis more difficult. The numbers and sizes of the spots can vary greatly, and occasionally the rash can be concentrated in an unusual location, such as the lower body or on the face. Several other skin conditions are similar in appearance to PLEVA and PLC. Certain skin fungus infections and syphilis may resemble this rash. Also, reactions to various internal medications, such as antibiotics, fluid pills, and heart medications, may mimic PLEVA or PLC. Various tests may be necessary to confirm diagnosis. Dr. Jacobs may order blood tests or even a biopsy of one of the spots to ascertain a definite diagnosis.

 

What is the treatment?

Treatment may include external and internal medications for itching. Only gentle, soothing measures should be used, as aggressive treatment has been known to cause the lesions to spread. If symptoms are mild, no treatment may be needed. Various types of soothing medicated lotions and lubricants may be prescribed to combat the rash. Individuals with PLEVA and PLC should take lukewarm, rather than hot, baths. Soap: Soap is bad for PLEVA and PLC involved skin. Dial, Zest, Lever, Safegaurd, Ivory, gels, and Irish Spring are among the worst. Soap removes skin oils needed to hold in moisture. If oils are removed, the skin develops cracks, fissures, and dry inflammation. Soap should not be used on dry or sensitive skin. Most of us use far too much soap. Actually, plain water is often just enough to cleanse the skin. If you can't live without soap, it's OK to use Dove soap for your face, feet, armpits, and groin. Avoid Allergic Items: PLEVA and PLC involved skin can become itchy when exposed to allergic type substances such as perfumes, dyes, conditioners, powders, anti-perspirants, hair sprays, grasses, plants, fragranced products, shampoos, unrinsed laundry detergents, fabric softener sheets, dog or cat hairs, carpets, chemicals, Aloe Vera, PABA, detergents, acrylic nails, polishes, nickel, elastic, latex, etc. Hair conditioners can induce itch! Please avoid perfumes. Bathing: Persons with PLEVA and PLC involved skin may bathe or shower twice daily: 1. Use no soap on dry or sensitive skin areas. You may use mild  Gentle Face and Body Cleanser, instead of soap. 2. After bathing, thoroughly lubricate your skin using  Replenishing Cream available OTC. 3. After your bath, you should not towel dry. Wipe off the water with your hands, then, apply a thin film of  Replenishing Cream to your entire body. This film will seal in your new moisture. 4. For shampoo, use OTC fragrance free  Gentle Shampoo. Mild lubricants, or anti-pruritic creams, or mild hydrocortisone creams may be used all over the body to soothe the inflammation. Oral antihistamines may be used to reduce itching. Oral corticosteroids may be needed in cases of severe inflammation. Mild sun exposure may help speed resolution of lesions; however, care must be taken to avoid sunburn. Expectations (prognosis): PLEVA and PLC usually resolves within several months, but symptoms may recur or continue. Strenuous activity may aggravate the rash.  Another important feature of treatment includes reassurance to the patient by the physician that PLEVA and PLC are not dangerous skin conditions. If there is any question of internal cancer, Dr. Jacobs can refer the patient to an oncologist.

 

PLEVA and PLC are uncommon, distinctive skin eruptions of unknown cause. PLEVA and PLC are usually mild, but unfortunately, can linger, even with proper treatment. PLEVA and PLC are non-contagious skin diseases. They can occur at any age but are more common in young people.