Tinea versicolor https://en.wikipedia.org/wiki/Tinea_versicolor
Tinea versicolor is a condition characterized by a rash on the trunk and proximal extremities. Most cases are caused by the fungus Malassezia globosa. These yeasts cause problems primarily under warm, humid conditions. Tinea versicolor is more common in hot, humid climates and in individuals who sweat heavily, and it often recurs each summer. Topical antifungal medications are recommended to treat tinea versicolor.

Treatment ― OTC Drugs
If the infection covers a large area of the body, a spray formulation may be the better choice.
#Ketoconazole
#Clotrimazole
#Miconazole
#Terbinafine
#Butenafine [Lotrimin]
#Tolnaftate
More information ― English
References Tinea Versicolor 29494106 
NIH
Pityriasis versicolor, also known as tinea versicolor, is a common, benign, superficial fungal infection of the skin. Clinical features of pityriasis versicolor include either hyperpigmented or hypopigmented finely scaled macules. The most frequently affected sites are the trunk, neck, and proximal extremities.
 Diagnosis and management of tinea infections 25403034
In prepubertal kids, the usual infections are ringworm on the body and scalp, while teenagers and adults often get athlete's foot, jock itch, and nail fungus (onychomycosis).