A heliotrope rash is a reddish purple rash that occurs as the first noticeable symptom of an inflammatory muscle disease called dermatomyositis. The rash takes its name from the heliotrope flower, which has purple petals.
Dermatomyositis causes progressive muscle weakness. In children, it can also damage the blood vessels.
What are the causes and risk factors?
The heliotrope rash can appear uneven and may be combined with a swollen eyelid.
A heliotrope rash is characteristic of dermatomyositis. Dermatomyositis is part of a group of muscle diseases called inflammatory myopathies or myositis (inflammation of muscle).
Dermatomyositis is a chronic autoinflammatory disease, with symptoms that may change over time. About a third of people who develop dermatomyositis as children recover, but the remainder continue to experience symptoms.
Researchers are unsure what causes dermatomyositis. It may be due to an underlying genetic predisposition that is triggered by a bacteria, virus, or even sunlight. Dermatomyositis is rare, affecting less than 10 out of every million people.
Women are twice as likely to get dermatomyositis as men. While it is possible to develop this condition at any age, it is more prevalent among children aged 5 to 10. Juvenile dermatomyositis affects children and can cause damage to the blood vessels as well as muscle weakness.
Other risk factors for dermatomyositis and the heliotrope rash that accompanies it include:
- cancer, particularly in older people (paraneoplastic syndrome)
- an autoimmune disorder or a predisposition to autoimmune diseases
- medications, infections, or injuries
- a viral infection
- sunburn or heavy sun exposure
A heliotrope rash is the first noticeable symptom of dermatomyositis. Image credit: Elizabeth M. Dugan, Adam M. Huber, Frederick W. Miller, Lisa G. Rider, 2010.
The heliotrope rash may be uneven and bumpy and often looks dry and irritated. It may burn or itch, or it may cause no symptoms other than reddened skin. In most people with dermatomyositis, a heliotrope rash appears before the muscular symptoms.
Over time, other symptoms may appear. In addition to skin lesions, flaky spots on the elbows and knees, and a rash on the knuckles, other signs of dermatomyositis include:
- Progressively worsening muscle weakness, particularly in the upper arms and upper thighs. Some people initially notice difficulty getting up from a seated position, or have trouble combing their hair.
- Sudden muscle weaknesses in the hips, back, or shoulders.
- Swelling and redness around the fingernails.
- Hard lumps under the skin, which are due to calcium deposits under the skin.
- Feelings of exhaustion and weakness.
- Difficulty swallowing, including sensations of choking or a lump in the throat.
- A hoarse voice that may accompany swallowing problems.
- Muscle pain, though not all people with dermatomyositis develop muscle pain.
People with dermatomyositis may be more vulnerable to a lung disorder called interstitial lung disease. This disease damages lung tissue and can make it difficult to breathe. Some people with interstitial lung disease develop lung stiffness and weakness.
The presence of specific antibodies in the blood may make it more likely that a person will develop interstitial lung disease.
Diagnosis and when to see a doctor
It is not possible to self-diagnose dermatomyositis based solely on the presence of a rash.
It can mimic some other conditions. Moreover, a rash on or around the eyes can pose a threat to vision, so it is vital to get an accurate diagnosis.
People who develop a painful or itchy rash on the eyes should see a doctor promptly, especially if the eyelids are swollen. If the eyelid is red or inflamed, but not painful, it is fine to wait for 1 to 2 days.
If the rash does not disappear, however, see a doctor. If an eyelid rash occurs along with other symptoms of dermatomyositis, ask a doctor for a referral to a specialist doctor, usually a rheumatologist.
Treatment may begin by ruling out other conditions, such as pink eye, an allergic reaction, or an injury to the eyelid. Other disorders that may cause a rash on the eye include lupus, HIV, and an inflammatory skin condition called lichen planus.
Diagnosing dermatomyositis can be difficult, so it is important to work with a dermatologist. Diagnostic tests may include:
- Blood tests: These can detect enzymes and autoantibodies associated with dermatomyositis and other muscle or neurological disorders.
- Biopsy: A biopsy of the rash, or of other irritated or inflamed areas of the skin. A biopsy removes a small sample of tissue, which is then stained and examined under a microscope.
- Imaging tests: Such as magnetic resonance imaging (MRI) of the muscles. These tests can show signs of muscle inflammation, even when a person has not yet experienced muscle weakness.
- Nerve conduction and EMG (electromyograms): These can also show early signs of muscle weakness, but they involve placing needles in the muscles, which can be painful.
Dermatomyositis pain may be improved with chiropractic therapies or massage.
There is no cure for dermatomyositis, though symptoms may get better or even go away on their own. The right treatment depends on symptoms, the person's overall health, and the specific antibodies present in their blood. Some treatment options include:
- Corticosteroid drugs: Topical lotions can help with itching and other skin symptoms. Systemic corticosteroids may suppress the immune system and prevent dermatomyositis from getting worse.
- Immunosuppressants: These are drugs that block activity in the immune system. Because dermatomyositis may be due to an overactive immune system, most people see an improvement in their symptoms. Immunosuppressants can put a person at risk of infections, however, so taking these drugs will depend on the person's overall health.
- Physical and exercise therapy: This can help resolve the symptoms by stimulating the affected area and maintaining a person's range of motion.
- Devices to support and assist the muscles: If the foot muscles become weak, a splint or shoe insert may help.
- Heat therapy: That can reduce inflammation in the muscles by increasing blood flow.
- Complementary therapies: Such as massage, acupressure, and chiropractic therapies can reduce pain.
A heliotrope rash is not dangerous, but it does point to a potentially serious underlying condition. Proper diagnosis can rule out cancer, which will need to be treated before dermatomyositis.
Prompt treatment can improve outcomes in people with dermatomyositis, making it possible to lead a normal life with minimal muscle weakness.