Youvanapiadaka or aananadooshika is general disorder of adolescents. Almost everyone in his or her life have at some stage such complication. Sushruta considers it as one of khudra roga resulted from vitiated Vata, Kapha and Rakta. When shalmali kantaka like eruptions are seen, it is said to be youvanapidaka. Face is said to be most affected site with prominence over cheek, nose, forehead and chin. It may also appear on chest or upper back. It is usually taken synonymous to Acne.
Acne is an inflammatory follicular, popular and pustular eruption involving the sebaceous apparatus. Depending upon the origin, causative factors and appearance various categorization for acne has been given viz., acne agnimata, acne vulgaris, acne albida, acne ciliaris, acne artificialis, asbestos acne, chlorine acne, bromide acne, acne cachectichorum, acne conglobata, cyctic acne etc. Several biological initiations are there for every type of acne.
Actually it arises due to blockage of sebaceous follicles. Out of number of different reasons behind its onset, four basic and important factors are as:
1. Excessive flow sebum: Androgens are first released in prepubertal period in both sexes. It is proved that sebaceous glands are best receptor for androgen. Androgens excite the glands to flow extra sebum along with attached follicles. This abnormally more sebum is onset of acne.
2. Desquamation of epithelial cells: Loose arrangement of keratinous squamae become denser due to desquamation of epithelial cells in sebaceous follicles. The reasons behind that are still not sure. This desquamation along with excessive flow of sebum form set the initiation of inflammatory or non-inflammatory lesion.
3. This combined form desquamation and excessive flow of sebum along the follicles bring the environment for anaerobic bacteria Propionibacterium acne to flourish.
4. The release the chemicals or caused to release the chemicals as result of autoimmune system to produce complete inflammation in form of papules, pustules, nodules etc.

In Ayurveda, the Nidana of Youvanapidaka is mentioned as:
1. Aaharaja nidana: Intake of food in ajeerna avasta, repeated consumption of food, excess intake of katu, guru, madhura ahara, dadhi, amla, teekshna, mamsa, junk food etc.
2. Viharaja nidana: Excess exposure to sun light, suppression of urge of vomiting, upavsa, jagarana, nidra viparyaya, not following dinacharya and rutuchrya.
3. Maanasika nidana: Atishoka, krodha, santap, kshobha etc.