Nail dystrophy and nail plate thinning

At a follow-up visit, a biopsy of the skin on the fingertips was performed, which showed lichenoid lymphocytic inflammatory infiltrate with associated hyperkeratosis, hypergranulosis, and acanthosis.

No fungal elements were seen. The findings were consistent with lichen planus.

^{Courtesy Dr. Catalina Matiz}

Follow-up picture which shows nail atrophy with pterygium

She continued topical betamethasone without much change. Topical tacrolimus later was recommended to use on off days of betamethasone, which led to no improvement. Narrow-band UVB also was started with minimal improvement. Unfortunately, at follow-up she had almost full destruction of the nail bed with associated pterygium.

Nail lichen planus (NLP) in children is not a common condition.¹ In a recent series from Chiheb et al., NLP was reported in 90 patients, of which 40% were children; a quarter of the patients reported having extracutaneous involvement as well.² In another childhood LP series,14 % of the children presented with nail disease.³ It can be a severe disease that, if not treated aggressively, may lead to destruction of the nail bed. This condition seems to be more prevalent in boys than girls and more prevalent in African American children.³ Unfortunately, in this patient’s case, the mother was hesitant to use systemic therapy and aggressive treatment was delayed.

Possible but not clear associations with autoimmune conditions such as vitiligo, autoimmune thyroiditis, myasthenia gravis, alopecia areata, thymoma, autoimmune polyendocrinopathy, atopic dermatitis, and lichen nitidus have been described in children with LP.

The clinical characteristics of NLP include nail plate thinning with longitudinal ridging and fissuring, with or without pterygium; trachyonychia; and erythema of the lunula when the nail matrix is involved. When the nail bed is affected, the patient can present with onycholysis with or without subungual hyperkeratosis and violaceous hue of the nail bed.⁴ NLP can have three different clinical presentations described by Tosti et al., which include typical NLP, 20‐nail dystrophy (trachyonychia), and idiopathic nail atrophy. Idiopathic nail atrophy is described solely in children as an acute and rapid progression that leads to destruction of the nail within months, which appears to be the clinical presentation in our patient.

Dr. Catalina Matiz

The differential diagnosis of nail dystrophy in children includes infectious processes such as onychomycosis, especially when children present with onycholysis and subungual hyperkeratosis. Because of this, it is recommended to perform a nail culture or submit a sample of nail clippings for microscopic evaluation to confirm the diagnosis of onychomycosis prior to starting systemic therapy in children. Fingernail involvement without toenail involvement is an unusual presentation of onychomycosis.

Twenty-nail dystrophy – also known as trachyonychia – can be caused by several inflammatory skin conditions such as lichen planus, psoriasis, eczema, pemphigus vulgaris, and alopecia areata. Clinically, there is uniformly monomorphic thinning of the nail plate with longitudinal ridging without splitting or pterygium.¹ This is a benign condition and should not cause scarring. About 10% of the cases of 20-nail dystrophy are caused by lichen planus.

Nail psoriasis is characterized by nail pitting, oil spots on the nail plate, leukonychia, subungual hyperkeratosis, and onycholysis, as well as nail crumbling, which were not seen in our patient. Although her initial presentation was of 20-nail dystrophy, which also can be a presentation of nail psoriasis, its rapid evolution with associated nail atrophy and pterygium make it unlikely to be psoriasis in this particular patient.

Patients with pachyonychia congenita – which is a genetic disorder or keratinization caused by mutations on several genes encoding keratin such as K6a, K16, K17, K6b, and possibly K6c – present with nail thickening (pachyonychia) and discoloration of the nails, as well as pincer nails. These patients also present with oral leukokeratosis and focal palmoplantar keratoderma.

The main treatment of lichen planus is potent topical corticosteroids.

For nail disease, topical treatment may not be effective and systemic treatment may be necessary. Systemic corticosteroids have been used in several pediatric series varying from a short course given at a dose of 1- 2 mg/kg per day for 2 weeks to a longer 3-month course followed by tapering.³ There are several protocols of intramuscular triamcinolone at a dose of 0.5 mg/kg in children in once a month injections for about 3 months that have been reported successful with minimal side effects.¹ Other medications reported useful in patients with NLP include dapsone and acitretin. Other treatment options include narrow-band UVB and PUVA.³

Dr. Matiz is a pediatric dermatologist at Southern California Permanente Medical Group, San Diego. Email her at pdnews@mdedge.com.

References

1. Arch Dermatol. 2001 Aug;137(8):1027-32.

2. Ann Dermatol Venereol. 2015 Jan;142(1):21-5.

3. Pediatr Dermatol. 2014 Jan-Feb;31(1):59-67.

4. Dermatological diseases, in “Nails: Diagnosis, Therapy, and Surgery,” 3rd ed. (Oxford: Elsevier Saunders, 2005, p. 105).