Skin diseases and allergic reactions 

Skin lightening, also known as skin bleaching, is the use of cosmetic or medicinal products to reduce the amount of melanin in the skin in order to obtain a lighter complexion or reduce areas of hyperpigmentation. While certain skin-lightening agents are appropriately prescribed for medical conditions such as melasma and post-inflammatory hyperpigmentation, the unsupervised or prolonged use of these products for cosmetic purposes can lead to serious local and systemic complications.

It is a cutaneous drug reaction that recurs at exactly the same site with repeated exposure to the agent.

Is a superficial fungal infection (dermatophytosis), on the scalp. It is quite common in children.

Epidermoid cyst (previously called an epidermal inclusion cyst or sebaceous cyst) is a common benign, slow-growing cystic lesion that develops from the epidermis. It is lined by stratified squamous epithelium and contains keratinous material rather than sebum. Epidermoid cysts may occur anywhere on the body but are most common on the face, neck, trunk, and back.

It is a common fungal infection caused by yeast.