From the Guidelines
Nail pitting is primarily caused by psoriasis, an autoimmune condition that affects about 50% of people with nail psoriasis, as evidenced by a case study published in the Journal of the American Academy of Dermatology 1. The most common causes of nail pitting include:
- Psoriasis, which can affect up to 50% of patients with nail psoriasis, and up to 90% of patients with psoriatic arthritis may have nail changes, including pitting, onycholysis, subungual hyperkeratosis, and the oil-drop sign 1
- Eczema
- Alopecia areata, an autoimmune condition causing hair loss
- Lichen planus, an inflammatory skin condition
- Fungal infections
- Certain medications, particularly those affecting the immune system
- Trauma to the nail matrix from injuries or habits like picking at nails
- Underlying health conditions such as connective tissue disorders like Reiter's syndrome Nail pitting occurs because these conditions interfere with normal keratin production in the nail matrix, creating small depressions as the nail grows. Treatment depends on identifying the underlying cause, and for psoriasis-related pitting, topical corticosteroids, vitamin D analogs like calcipotriol, or systemic medications like methotrexate or biologics may be prescribed 1. If you notice persistent nail pitting, consult a dermatologist for proper diagnosis and treatment.
From the Research
Causes of Pitting Nails
Pitting nails can be caused by various factors, including:
- Psoriasis: Nail psoriasis is a common condition that can cause pitting, leukonychia, red lunula, and nail dystrophy 2, 3, 4
- Systemic diseases: Certain systemic diseases, such as connective tissue disorders, can cause pitting of the nails 5
- Skin conditions: Conditions like alopecia areata, lichen planus, atopic dermatitis, and ichthyosis vulgaris have been associated with trachyonychia, a condition characterized by nail plate roughness, pitting, and ridging 6
- Other factors: Pitting can also be caused by nail trauma, exposure to cold temperatures, or other environmental factors 5
Associated Conditions
Pitting nails can be associated with various conditions, including:
- Psoriatic arthritis: Nail psoriasis is correlated with more severe disease and a higher risk of psoriatic arthritis 2
- Connective tissue disorders: Patients with telangiectasia, koilonychia, or pitting of the nails may have connective tissue disorders 5
- Sarcoidosis: Trachyonychia has been associated with sarcoidosis, although the causal relationship is often challenging to demonstrate histologically 6
Prevalence and Characteristics
The prevalence and characteristics of pitting nails can vary depending on the underlying condition, including:
- Incidence: Finger nail pitting was present in 37% of patients with psoriasis, and its incidence increases with duration and severity of the disease 3
- Frequency: Pitting was the commonest finding in fingernails (60.5%) in patients with nail psoriasis 4
- Association: Pitting is often associated with other nail abnormalities, such as subungual hyperkeratosis, onycholysis, and dotted capillaries in hyponychium, proximal, and lateral nail folds 4