Nail Pitting: Causes, Conditions & Treatment | DPM

Quick answer: Nail pitting — small dents or depressions in the nail surface — is most often linked to psoriasis, but it can also accompany eczema, alopecia areata, or reactive arthritis. Occasional shallow pits are usually harmless; widespread or worsening pitting, especially with skin or joint symptoms, should be evaluated by a doctor or podiatrist.

Those small dents in your nail plate aren’t random. Every pit forms the same way — a tiny group of abnormal parakeratotic cells near the nail matrix produces defective nail plate that crumbles away, leaving a depression — but the reason that abnormal cell cluster forms is completely different depending on which condition is driving it. Getting that cause right is the entire game, because treating psoriatic nail pitting with antifungal medication (a common mistake) does nothing.

What Is Nail Pitting?

Nail pitting refers to small, sharply defined depressions (pits) on the dorsal surface of the nail plate. They range from 1–2 mm in diameter and can be shallow or deep. Pitting is the result of focal defects in the nail plate produced when clusters of parakeratotic cells (immature, incompletely keratinized cells) form in the proximal nail matrix. As these defective cells reach the surface and desquamate, they leave the characteristic indentation.

Pitting is most visible in the fingernails, but toenail pitting occurs across all five conditions — and in a podiatry clinic, toenail pitting is often the first sign we see that points toward a systemic inflammatory diagnosis the patient hasn’t received yet. In our practice, I’ve diagnosed new psoriatic arthritis and alopecia areata through toenail examination during routine foot visits.

Not to be confused with: Beau’s lines (transverse ridges or grooves — a different finding indicating temporary growth arrest) or onychomycosis (fungal infection causing thickening, discoloration, and crumbling — not discrete pits). The presence of isolated small round depressions on an otherwise normal-appearing nail is the hallmark of pitting specifically.

Cause #1: Psoriasis (Most Common)

Psoriasis is the single most common cause of nail pitting, accounting for the majority of cases seen in clinical practice. Nail involvement occurs in approximately 50% of people with skin psoriasis and up to 80% of those with psoriatic arthritis. Psoriatic nail pitting has a characteristic pattern: pits tend to be numerous (10+ per nail in active disease), irregularly distributed, and relatively deep. They are often described as having an “ice-pick” quality.

Crucially, psoriatic nail pitting almost never appears in isolation. Look for these co-occurring nail findings that are highly specific for psoriasis:

• Oil drop sign (salmon patch): A translucent yellowish-brown spot under the nail plate resembling a drop of oil — caused by psoriatic onycholysis beginning under the nail. This finding is pathognomonic (essentially diagnostic) for psoriasis when present.
• Onycholysis: Separation of the nail plate from the nail bed, beginning at the distal tip. In psoriasis, the onycholytic border often has a yellow-brown rim.
• Subungual hyperkeratosis: Buildup of chalky white material under the nail plate.
• Nail plate crumbling: In severe psoriasis, the entire nail plate becomes dystrophic.

Skin psoriasis is often but not always present. Nail psoriasis can occur in the absence of visible skin plaques, particularly in psoriatic arthritis. Joint symptoms (particularly in the DIP joints — the joints closest to the fingernail) alongside nail pitting strongly suggest psoriatic arthritis and warrant rheumatologic evaluation.

Cause #2: Alopecia Areata

Alopecia areata, the autoimmune hair loss condition, causes nail pitting in 10–66% of affected individuals — a wide range because it correlates with disease severity. The pitting pattern in alopecia areata is highly distinctive and different from psoriasis: pits are typically geometric, regularly arranged, and shallow, often appearing in transverse or longitudinal rows — sometimes described as a “geometric” or “grid-like” pattern.

The associated finding that clinches the diagnosis: the patient has patchy hair loss on their scalp, eyebrows, eyelashes, or body. When nail pitting appears in a patient with known alopecia areata, no further workup for the nail finding is needed — it’s the same autoimmune process affecting the nail matrix.

Beyond pitting, alopecia areata can also cause trachyonychia (rough, sandpaper-like nail surface) and red lunulae (reddening of the normally pale crescent at the nail base). These co-occurring features, combined with the geometric pitting pattern and hair loss history, make the diagnosis straightforward clinically.

Cause #3: Eczema / Atopic Dermatitis

Eczema (atopic dermatitis) causes nail pitting through periungual inflammation — the inflamed skin around the nail matrix disrupts the orderly production of nail plate cells. The pitting in eczema is typically coarser and more irregularly sized than psoriatic pitting, and importantly, it’s accompanied by the classic skin findings of eczema: dry, inflamed, itchy skin around the nail folds and on the periungual skin.

In atopic patients, chronic nail fold scratching and rubbing compounds the pitting by directly disrupting the matrix through external trauma. The combination of irregular pitting, nail fold inflammation, and dry atopic skin elsewhere (antecubital and popliteal fossae are the classic locations) identifies eczema-related nail pitting.

Unlike psoriasis, eczema nail pitting does not typically produce an oil drop sign, onycholysis, or subungual hyperkeratosis — those are psoriasis-specific features.

Cause #4: Reactive Arthritis (Reiter’s Syndrome)

Reactive arthritis (formerly called Reiter’s syndrome) is an autoimmune arthritis triggered by a preceding infection — most commonly chlamydia or enteric organisms (Salmonella, Shigella, Campylobacter, Yersinia). Nail pitting occurs in reactive arthritis as part of a broader nail and skin involvement that closely mimics psoriasis and is sometimes called “keratoderma blenorrhagicum” when it affects the palms and soles.

The clinical distinction from psoriasis relies on history: reactive arthritis patients typically recall a preceding urogenital or gastrointestinal infection 1–6 weeks before joint and nail symptoms began. The classic triad — arthritis, urethritis, and conjunctivitis — helps identify it, though the complete triad is present in only about 30% of cases.

Nail findings in reactive arthritis can include pitting, onycholysis, and subungual hyperkeratosis — nearly identical to psoriasis — which is why the preceding infection history is the most important differentiating feature.

Cause #5: Lichen Planus

Lichen planus is an inflammatory condition affecting skin, mucous membranes, and nails. Nail lichen planus produces pitting as part of a more aggressive nail involvement than the other conditions — lichen planus causes the most destructive nail changes of any of the five causes listed here.

Beyond pitting, look for these lichen planus–specific nail findings: longitudinal ridging (deep vertical lines running the full length of the nail), nail thinning, and most distinctively, pterygium unguis — where the cuticle (proximal nail fold) fuses with the nail plate and grows distally, permanently destroying the nail matrix in that area. Pterygium unguis is essentially pathognomonic for lichen planus when present.

Skin lichen planus produces flat-topped, purple, polygonal pruritic papules — often described by the “6 P’s” (planar, purple, polygonal, pruritic, papules, plaques). Oral lichen planus produces lacy white patches (Wickham’s striae) on the buccal mucosa. The presence of any of these alongside nail pitting points toward lichen planus.

How Nail Pitting Is Diagnosed

In the vast majority of cases, nail pitting can be diagnosed clinically — meaning by examination of the nails and surrounding skin, combined with the patient’s history. A nail biopsy is reserved for ambiguous cases or when the diagnosis would change management significantly (e.g., ruling out a rare cause). Here’s the examination approach we use:

• Count and characterize the pits: Numerous deep irregular pits → psoriasis; shallow geometric rows → alopecia areata; irregular coarse pits with inflamed folds → eczema.
• Look for co-occurring nail findings: Oil drop sign → psoriasis; pterygium → lichen planus; trachyonychia → alopecia areata.
• Examine the periungual skin: Inflamed folds → eczema; psoriatic plaques → psoriasis; purple papules → lichen planus.
• Ask about scalp hair loss: Positive → alopecia areata.
• Ask about preceding infection and joint symptoms: Recent GI/GU infection + joint pain → reactive arthritis; DIP joint arthritis → psoriatic arthritis.
• Check mucous membranes: White lacy patches → lichen planus.

Blood tests (ANA, RF, anti-CCP) may be ordered when psoriatic arthritis or reactive arthritis is suspected. A dermatology or rheumatology referral is appropriate when systemic disease is suspected based on this examination.

Treatment Options by Cause

There is no universal treatment for nail pitting — the treatment is entirely determined by the underlying cause. This is why accurate diagnosis matters so much.

Psoriasis: Topical steroids or calcipotriol under occlusion applied to the proximal nail fold (the skin just behind the nail, overlying the matrix) for 3–6 months. For moderate to severe disease, intralesional triamcinolone injections into the nail matrix are effective. Biologic agents (TNF inhibitors, IL-17/23 inhibitors) dramatically improve nail psoriasis in patients who require systemic therapy for skin or joint disease — biologics can produce near-complete nail clearing in some patients.

Alopecia areata: Treatment targets the underlying autoimmune process. Intralesional triamcinolone to the nail matrix, oral JAK inhibitors (baricitinib, ritlecitinib — now FDA-approved for alopecia areata), and topical immunotherapy. Nail pitting typically improves in parallel with hair regrowth.

Eczema: Topical corticosteroids to the nail folds and periungual skin. Addressing the underlying atopic disease (dupilumab for moderate-severe atopic dermatitis) often improves nail changes as a secondary benefit. Nail fold occlusion with petroleum jelly at night helps retain moisture and reduce inflammation.

Reactive arthritis: Treatment of the triggering infection if still active, NSAIDs for joint symptoms, and topical steroids for nail and skin involvement. Most cases are self-limiting within 3–12 months, and nail pitting resolves with disease remission.

Lichen planus: This is the most treatment-resistant of the five causes. Systemic corticosteroids, hydroxychloroquine, and retinoids are used for extensive involvement. Nail lichen planus often leaves permanent nail dystrophy even after treatment, particularly when pterygium has formed — early treatment before pterygium formation is critical to preserving the nail.

The Most Common Mistake with Nail Pitting

The most common mistake I see — both from patients self-treating and from initial clinical evaluations — is treating nail pitting as nail fungus. Onychomycosis and nail pitting can both cause nail discoloration and abnormal appearance, but they are completely different conditions.

Antifungal medication (oral terbinafine, topical ciclopirox) has zero effect on nail pitting caused by psoriasis, alopecia areata, eczema, reactive arthritis, or lichen planus. Patients taking a 3-month course of oral antifungal therapy for what is actually psoriatic nail disease are receiving an unnecessary medication with real side effects (hepatotoxicity risk with oral terbinafine) while the actual condition goes untreated.

A nail culture or KOH preparation (looking for fungal elements under the microscope) takes 5 minutes and definitively rules out fungal involvement. If both the culture and KOH are negative, nail pitting is inflammatory, not fungal — and the workup described above should proceed.

Frequently Asked Questions

Can nail pitting go away on its own?
It depends on the cause. Reactive arthritis–related nail pitting often resolves spontaneously within months as the condition self-limits. Psoriasis, alopecia areata, and lichen planus are chronic conditions — pitting tends to persist or recur without treatment of the underlying disease.

Is nail pitting always a sign of psoriasis?
No — psoriasis is the most common cause, but alopecia areata, eczema, reactive arthritis, and lichen planus all produce nail pitting. Each has distinguishing features that allow clinical differentiation.

Can nail pitting be caused by fungus?
No. Fungal nail infection (onychomycosis) causes thickening, discoloration, and crumbling — not discrete small pits. These are different conditions. If you have nail pitting, antifungal medication will not help.

What does nail pitting look like vs. normal nail texture?
Normal nails have subtle longitudinal ridges that increase with age. Nail pitting consists of discrete, sharply defined punctate depressions — like small ice-pick holes — distributed across the nail plate surface. They are distinctly different from ridges in that they are round depressions rather than lines.

Does nail pitting mean I have psoriatic arthritis?
Not necessarily, but nail pitting in the context of any joint pain (especially DIP joint swelling or stiffness) significantly raises the probability of psoriatic arthritis and warrants rheumatology evaluation. Up to 80% of patients with psoriatic arthritis have nail involvement.

The Bottom Line

Nail pitting is a clinical sign, not a diagnosis. The five conditions that cause it — psoriasis, alopecia areata, eczema, reactive arthritis, and lichen planus — have completely different treatments, systemic implications, and long-term trajectories. Getting the right diagnosis is straightforward in most cases with careful clinical examination of the nail pattern, periungual skin, and accompanying history.

If you have nail pitting and haven’t received a clear diagnosis of the underlying cause, that’s the first step. Don’t accept “try antifungal treatment and see” as an answer — if there’s no fungus, that course of treatment is unnecessary and ineffective.

Sources

1. Jiaravuthisan MM, et al. “Psoriasis of the nail: anatomy, pathology, clinical presentation, and a review of the literature.” J Am Acad Dermatol. 2007.
2. Tosti A, et al. “Nail disorders in patients with alopecia areata.” J Am Acad Dermatol. 2003.
3. Richert B, et al. “Nail lichen planus: epidemiology, clinical aspects, and management.” Dermatol Clin. 2021.
4. Mease PJ, et al. “Nail psoriasis in psoriatic arthritis.” Ann Rheum Dis. 2024.
5. Psoriatic Nail Disease: Clinical Features and Current Therapeutic Options — PubMed

Related nail-surface guides

Other nail-surface changes worth comparing:

• Horizontal ridges on toenails (Beau’s lines)
• Toenail problems: complete guide
• Nail & skin conditions hub

Related toenail conditions: vertical nail ridges, horizontal lines on toenails, and toenails peeling off.