Genetics of PsA
- Genetic factors play a role in PsA. People with PsA often have a first-degree relative (parents or siblings) with either psoriasis or PsA, and occasionally uveitis (inflammatory eye condition), Crohn’s disease or ulcerative colitis (inflammatory bowel disease)
- Despite this, the children of people with PsA usually do not develop PsA, because PsA is thought to occur when a genetically susceptible individuals exposed to some sort of environmental trigger (eg a virus, trauma, toxin, hormones etc).
- Several genes have been identified that are linked to PsA. However, many are also linked to other related conditions, eg psoriasis. So far, only six genes have been found that appear to predispose people only to PsA, independently of skin psoriasis.
- Research is ongoing to identify genes that might indicate if a person might get mild or severe disease, or if they might get certain features of the disease, eg back problems, but not others.
Nail changes in PsA
- Nail disease occurs in both hands and feet.
- Nail changes occur in up to 90% of people with PsA compared to 46% of those with psoriasis alone.
- People with psoriasis or PsA commonly complain of brittle nails that easily break, lift at the ends or are discoloured. Observed nail changes include:
- onycholysis (lifting of the nail from the nail bed)
- hyperkeratosis (thickening of the nail)
- salmon patch – brown discoloration of the nail (often with onycholysis)
- ridging (both transverse and longitudinal)
- nail plate crumbling.
- Many of these features occur in healthy people and are nothing to worry about. However the combination of pitting plus onycholysis, or the presence of more than 20 pits, usually occurs in either psoriasis or PsA. Many patients with nail changes will never develop PsA.
- People with PsA with severe nail changes often have more arthritic joints, especially those joints in the vicinity of the affected nail.
- People with PsA are often embarrassed by the appearance of their nails. It is important to mention concerns to your doctor, so that treatment options may be discussed. However, nails are notoriously difficult to improve.
- People with PsA of the nails may find they need assistance with trimming and cutting, particularly their toenails.
PsA and pregnancy
- For women, the time after having a baby and the time during menopause are two common periods for developing PsA.
- There is no significant increase in miscarriage in women with PsA and no other unusual effects on the baby.
- The activity of PsA or psoriasis during pregnancy is variable. Usually the arthritis temporarily improves, but may flare after delivery.
- Non-steroidal anti-inflammatory drugs, eg ibuprofen, naproxen and diclofenac, should be used with caution before and during pregnancy (especially in the first trimester).
- Medications such as methotrexate and leflunomide should never be used in the months leading up to pregnancy, during or immediately after pregnancy due to their harmful effects on the child.
- If you are considering starting a family you should always discuss your treatment options with your doctor or healthcare provider.
This article is adapted from the Psoriatic Arthritis - Did You Know leaflet.
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Always consult a doctor or your healthcare provider