Why pain remains after skin healing
After a childhood illness, the chickenpox virus persists for life in sensory nerve ganglia. When immunity decreases, it is activated, travels down the nerve to the skin and causes shingles. Inflammation damages nerve fibers and their sheaths, and also changes the functioning of the dorsal horns of the spinal cord: the nervous system begins to amplify any signals. As a result, the skin heals, and the rebuilt pain pathways continue to work on their own. This is why pain is called neuropathic - it comes from the damaged nerve, and not from inflamed tissue.
- Damage to sensory fibers by virus
- Restructuring Pain Processing in the Spinal Cord
- Formation of foci of increased excitability
- Decreased self-pain control
- Death of some nerve endings in the skin
Who risks more
The main factor is age: after 50 years, the likelihood of persistent pain increases sharply, and after 70 years it becomes even higher. The way the acute period progressed is also important: the stronger the pain before the rash appeared and the more extensive the rash, the higher the risk. People with reduced immunity are separately identified - after chemotherapy, with long-term use of hormones, with severe chronic diseases.
- Age over 50
- Severe pain even before blisters appear
- Extensive rash and severe inflammation
- Damage to the face and eye area
- Diabetes mellitus and cancer
- Taking immunosuppressive drugs
- Late initiation of antiviral treatment
How it manifests itself
The pain is located strictly in the area of former rashes, most often on the chest along the intercostal space or on the face. It can be constant burning, paroxysmal shooting or a combination. A characteristic symptom is allodynia, when the touch of clothing, wind or water is perceived as painful, and the person begins to avoid dressing and washing. In the same area there are often areas of decreased sensitivity, discolored skin and scars. Constant pain disrupts sleep, reduces appetite and often leads to depressed mood.
- Burning or shooting pain in the area of the former rash
- Pain from light touch
- Itching and crawling sensation
- Numbness and decreased sensitivity near the pain area
- Sleep disturbance and decreased performance
- Anxiety and depressed mood
Diagnostics
The diagnosis is made clinically: typical pain in the area of the previous rash, which persists for more than three months, does not require confirmation by tests. The doctor clarifies when the shingles occurred, assesses the nature of the pain using questionnaires for neuropathic pain, and checks sensitivity in the affected area. Additional research is needed in controversial cases: when pain occurs without a rash, is localized atypically, or is accompanied by weakness in the limbs. Then a herniated disc, tumor, heart disease and chest disease are ruled out.
- Examination by a neurologist and sensitivity assessment
- Neuropathic pain questionnaires
- General and biochemical blood test if the picture is unclear
- MRI of the spine for limb weakness
- Examination by an ophthalmologist for damage to the eye area
- ECG for pain in the left half of the chest
Treatment and prevention
Conventional anti-inflammatory drugs do not work well for neuropathic pain. The basis of treatment is drugs that reduce the excitability of nerve fibers - anticonvulsants and some antidepressants in doses selected by the doctor; the effect develops gradually, over 1–2 weeks. Additionally, local agents with an analgesic effect, therapeutic blockades, magnetic therapy and laser therapy are used. The best way to reduce the risk is to start antiviral treatment in the first 72 hours of shingles and treat the acute phase early. All medications are prescribed by a doctor: dose selection and taking into account other diseases are important here.
- Anticonvulsants for neuropathic pain
- Separate groups of antidepressants in analgesic doses
- Local anesthetic patches and ointments as prescribed
- Paravertebral and other blockades
- Magnetic therapy, laser therapy, transcutaneous electrical stimulation
- Early antiviral treatment of herpes zoster
- Working with a psychologist for long-term pain and sleep disturbances