At the 2020 Winter Clinical Dermatology Conference, Boni E. Elewski, MD, shared practical tips for dermatologists looking to approach a variety of nail presentations. The presentation covered pearls on treating the solitary abnormal nail, inflammatory nail disorders, and common nail infections.
In her first tip, Dr Elewski discussed how diagnosing the solitary abnormal nail can be a relatively easy process. When the patient presents with a solitary abnormal nail, the dermatologist should take steps to determine the differential diagnosis, including biopsy, x-ray, and culture. However, if malignancy is suspected, x-ray should be used first to note of soft tissue growth. Dermoscopy can be especially useful tool for differential diagnosis as well, as shown in a case report by Dr Elewski that demonstrated a honeycomb pattern on a solitary abnormal nail presenting with onychomatricoma.
Dermatologists should also pay attention to longitudinal erythronychia. When multiple nails present with longitudinal erythronychia, the underlying cause is an inflammatory process such as lichen planus, graft vs host disease, or drug related. When longitudinal erythronychia is localized to one nail, it is most commonly a sign of onychopapilloma, but it can also be glomus tumor, verrucae, warty dyskeratoma, and isolated lichen planus. Cancerous causes include basal cell carcinoma, Bowen’s disease, and amelanotic melanoma.
In short, Dr Elewski said, if only one nail is involved, the abnormal nail is likely caused by a tumor.
Dr Elewski’s second tip regarded diagnostic pearls for inflammatory nail disorders. For example, nail psoriasis occurs in up to 78% of patients with psoriasis and is more common in patients with psoriatic arthritis and genital psoriasis. It usually involves several nails and both hands and may be the only sign of psoriasis in 5% of patients. When dermatologists consider the nail-joint relationship, particularly the distal and proximal interphalangeal (DIP, PIP) joints, the relationship between nail psoriasis and psoriatic arthritis should be no surprise.
“It’s helpful, in my experience, when you have an abnormal nail to feel the DIP and PIP joints,” explained Dr Elewski, “and talk to the patient about pain, difficulty moving, morning stiffness, and so forth, to help nail the diagnosis.”
There are three additional features to consider to help diagnosis nail psoriasis:
- Irregular pitting of the nail plate;
- Salmon-colored patches or oil spots on the nail bed; and
- Onycholysis with erythematous borders
Lichen planus can occur in the nail bed as well. “When I walk into a room and see really horrible nails, what do I think of? Lichen planus,” said Dr Elewski. This often presents with longitudinal nail plate fissures, nail plate thinning, longitudinal erythronychia, angel wing deformity, dorsal pterygium, and anonychia. Treatment of nail lichen planus is paramount and should be considered a nail emergency. Treatment options include intralesional steroids to the nail matrix at the proximal nail fold, intramuscular or oral steroids, and topical treatments with potent corticosteroids and tazarotene. However, when the nail presents with dorsal pterygium, the nail matrix is dead, so no treatment is going to be effective. Notably, one-third of nail lichen planus progress despite treatment.
The final tip was regarding treatment of nail infections. Dr Elewski discussed three major infections:
- Onychomycosis - Trichophyton rubrum is the most common isolate. This infection is treated with terabinafine 250 mg daily for 90 days (though dermatologists should be careful regarding T rubrum’s growing resistance), itraconazole 400 mg daily for 1 week per month for 4 months or 200 mg daily for 3 months, and fluconazole 200 mg to 400 mg once weekly (such as “Fungal Fridays” or “Toes-day”).
- Pseudomonas – If the nail is green in color, it is probably Pseudomonas infection. It can occur concomitantly with dermatophyte infection, and an x-ray in chronic infection or painful nails should be done to rule out osteomyelitis. Treatment options include vinegar soaks, half white vinegar/half isopropyl alcohol drops under nail, ciprofloxacin otic drops, and oral antibiotics, but most importantly, the affected area should be kept dry.
- Candida – A blackish nail, towards a lateral edge with edema and loss of cuticle, may be caused by Candida infection. Treatment includes oral fluconazole 200 mg daily for one week.
Reference
Elewaki BE. Nail tips. Presented at: 2020 Winter Clinical Dermatology Conference; Kohala Coast, HI; January 18, 2020.
