Tinea nigra: causes, symptoms, diagnosis, and treatment

Tinea nigra usually occurs in the palms and is thus termed tinea nigra palmaris, characterized by non-itchy, brown or black macules with thin, pityroid scales, which is also known as pityriasis nigra.


Causes

The pathogens of this disease are cladsporium wernecki and cladsporium mansonii.


Signs and Symptoms

Skin lesions are varying in number, different sized, various shaped, light brown, brown, or black macules, fusing with each other, resembling contaminated by ink or silver nitrate solution, without papules, vesicles, or inflammation, without raised edges. Sometimes flat surface is slightly raised, which is like a brown or black piece of paper attached to the skin. There are no any subjective symptoms, and scratches can cause fine, pityroid scales. The illness occurs usually on the palms, occasionally on the soles, back, and chest.

Figure 1 tinea nigra


Histopathology

In the stratum corneum of the skin, light brown, short, thick, curved or straight, septate hyphae can be seen, and sometimes spores can also be observed.


Diagnosis

On the basis of typical clinical presentations and positive fungal examinations, the disease can be diagnosed. KOH examination can assist in the diagnosis.


Treatment

Keratolytic agents are very effective. Generally, topical compound benzoic acid ointment, 2% iodine tincture, 2% salicylic acid, or 3% sulfur ointment is effective. Grifomycin is ineffective in the treatment of this disease.