Koilonychia
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Koilonychia, also known as spoon nails, is a disorder of the shape of the nail plate, which becomes flattened and then concave in the central part and raised at the edges. The change may involve a single nail or multiple fingernails and toenails. Koilonychia is a clinical sign, not a distinct disease with a single cause. It often accompanies iron deficiency, chronic trauma, inflammatory diseases of the nail apparatus, or fungal infections. Less commonly, it is associated with systemic diseases and genetic conditions. The evaluation of spoon nails requires considering age, duration of the changes, the number of affected nail plates, and symptoms involving the skin and the entire body.
Koilonychia - what does it look like?
A typical feature of koilonychia is concavity of the central part of the nail plate, resembling the shape of a spoon. The lateral and distal edges of the nail may turn upward. In advanced cases, the depression holds a small drop of water. This is an auxiliary clinical observation, not a standalone diagnostic test.
The nail plate may simultaneously be:
- thin, soft, and prone to deformation,
- brittle or splitting at the free edge,
- dull, rough, or ridged,
- flattened before developing full concavity,
- slower-growing in the presence of concomitant nutritional or blood supply disorders.
Koilonychia can affect a single nail, several plates, or nearly all nails. A change limited to a single plate more often indicates trauma, chronic pressure, local skin disease, or infection. Symmetrical involvement of multiple nails increases the likelihood of systemic causes.
In infants and young children, transient flattening or spooning of the toenails may represent a developmental variant associated with a thin nail plate. In an adult, newly developed koilonychia requires medical evaluation, especially when accompanied by weakness, pale skin, exertional dyspnea, palpitations, hair loss, a burning sensation of the tongue, difficulty swallowing, or menstrual disorders.
The differential diagnosis includes, among others, brittle nails, onycholysis (i.e., separation of the nail plate from the nail bed), post-traumatic dystrophies, nail psoriasis, lichen planus, and onychomycosis.
Koilonychia - what can it indicate?
The most well-known clinical association is iron deficiency, which can occur even before the development of anemia. The presence of koilonychia in itself does not confirm a deficiency, but constitutes an indication to evaluate iron metabolism. In some patients, the deficiency is accompanied by chronic fatigue, poorer exercise tolerance, headaches, pallor, angular cheilitis, dry skin, hair loss, or pica, such as the urge to chew ice.
Koilonychia may occur in the course of:
- iron deficiency with or without anemia,
- chronic blood loss, including heavy menstrual bleeding or gastrointestinal bleeding,
- malabsorption disorders, especially celiac disease and inflammatory bowel diseases,
- psoriasis, lichen planus, and other dermatoses involving the nail matrix,
- onychomycosis,
- hypothyroidism or hyperthyroidism,
- peripheral circulatory disorders and Raynaud's phenomenon,
- autoimmune diseases, including systemic lupus erythematosus,
- hemochromatosis, i.e., excessive iron accumulation,
- rare genetic syndromes, such as nail-patella syndrome.
The combination of koilonychia, iron deficiency anemia, and difficulty swallowing requires special evaluation. Such a presentation may correspond to Plummer-Vinson syndrome, in which webs form in the upper esophagus. This condition requires gastroenterological and laryngological diagnostics.
The nail change serves as a diagnostic clue. The diagnosis of a systemic disease is based on medical history, physical examination, and appropriately selected additional tests.
Koilonychia - where does it come from?
The nail plate is formed mainly in the nail matrix. Disturbances in its keratinization, thickness, and mechanics can lead to the loss of physiological convexity. The exact mechanism of koilonychia depends on the cause. Significance is attributed to thinning of the plate, changes in connective tissue, impaired matrix function, and uneven growth of its proximal and distal parts.
The causes of koilonychia are divided into:
- acquired systemic, primarily associated with iron deficiency, gastrointestinal diseases, hormonal disorders, or systemic diseases;
- acquired local, resulting from footwear pressure, microtrauma, manual labor, contact with water, detergents, solvents, or petroleum products;
- dermatological, including inflammatory diseases of the nail matrix and nail bed, as well as fungal infections;
- congenital and hereditary, occurring familially or as part of a genetic syndrome;
- idiopathic, when extensive diagnostics do not reveal an identifiable cause.
In iron deficiency, nail changes usually develop gradually. The source of the deficiency may be low iron intake, increased demand during periods of growth or pregnancy, blood loss, or impaired absorption. In menstruating women, heavy bleeding is a common cause. In men and postmenopausal women, confirmed iron deficiency requires a particularly thorough evaluation of the gastrointestinal tract.
Repetitive pressure and trauma usually cause asymmetrical changes. This applies, among others, to toenails compressed by footwear and fingernails exposed to intensive mechanical work. The condition may be exacerbated by frequent filing of the nail plate surface, aggressive removal of nail styling, and prolonged contact with irritants.
Koilonychia - what tests to perform?
Diagnosis begins with a dermatological or internal medicine examination. The doctor evaluates all nails, skin, hair, and mucous membranes, and also asks about diet, menstrual cycles, chronic diseases, gastrointestinal complaints, medications taken, occupation, nail styling used, and family history of similar changes.
A basic panel of tests may include:
- complete blood count with assessment of hemoglobin concentration, hematocrit, and red blood cell indices,
- ferritin, which reflects iron stores,
- iron level, transferrin or total iron-binding capacity, and transferrin saturation,
- C-reactive protein, facilitating the interpretation of ferritin in the presence of inflammation,
- thyroid-stimulating hormone, and depending on the result, also free thyroxine.
The scope of further tests depends on the medical history and initial results. If celiac disease is suspected, tissue transglutaminase antibodies of the immunoglobulin A class are measured along with total immunoglobulin A levels. Confirmed iron deficiency may require diagnostic evaluation to determine the cause of blood loss, including gynecological or gastroenterological assessment.
Thickening, discoloration, crumbling, and separation of the plate support performing a mycological examination. The material can be evaluated microscopically, via culture, or using molecular methods. Confirming the infection before antifungal treatment increases the accuracy of therapy.
Dermoscopy of the nail apparatus helps evaluate the structure of the nail plate and surrounding tissues. A biopsy of the matrix or nail bed is reserved for atypical, persistent lesions that raise suspicion of inflammatory or neoplastic disease.
Koilonychia - can it be cured?
The prognosis depends on the cause and the extent of damage to the nail matrix. Koilonychia associated with a reversible deficiency, infection, dermatosis, or trauma may gradually resolve after effective causal treatment. Improvement is visible as the new plate grows out. Fingernails regrow within a few months, and the complete replacement of toenails usually takes a dozen or so months.
Management may include:
- iron supplementation following laboratory confirmation of the deficiency and concurrent treatment of the source of iron loss,
- therapy for thyroid, intestinal, skin, or vascular disease,
- antifungal treatment following confirmation of an infection,
- reducing pressure, microtrauma, contact with detergents, and aggressive preparation of the nail plate,
- using protective gloves, emollients, and lubricating preparations for the nail folds,
- keeping the nails short and gently smoothing the free edge.
At Ambasada Urody, procedures supporting the care of weakened nails are available: podiatric consultation and care, cosmetic manicure, cosmetic or medical pedicure, IBX System, Japanese P.Shine manicure and pedicure, and nail regenerating treatments. Their role is professional preparation, protection, smoothing, or temporary strengthening of the plate. They complement the diagnosis and treatment of the cause of koilonychia.
In the case of active nail disease, the scope of the procedure should be determined by a dermatologist or podiatrist. Intensive polishing, extensions, and long-lasting styling should be postponed until the origin of the deformity is clarified and the condition of the plate improves.
